WO2022070071A1 - Dihydroorotate dehydrogenase inhibitors - Google Patents

Dihydroorotate dehydrogenase inhibitors Download PDF

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Publication number
WO2022070071A1
WO2022070071A1 PCT/IB2021/058908 IB2021058908W WO2022070071A1 WO 2022070071 A1 WO2022070071 A1 WO 2022070071A1 IB 2021058908 W IB2021058908 W IB 2021058908W WO 2022070071 A1 WO2022070071 A1 WO 2022070071A1
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Prior art keywords
methyl
fluoro
isopropyl
quinolizin
hydroxypropan
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PCT/IB2021/058908
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French (fr)
Inventor
Lindsey DERATT
Scott Kuduk
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Janssen Biotech, Inc.
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Publication of WO2022070071A1 publication Critical patent/WO2022070071A1/en

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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61PSPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P35/00Antineoplastic agents
    • A61P35/02Antineoplastic agents specific for leukemia
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D471/00Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, at least one ring being a six-membered ring with one nitrogen atom, not provided for by groups C07D451/00 - C07D463/00
    • C07D471/02Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, at least one ring being a six-membered ring with one nitrogen atom, not provided for by groups C07D451/00 - C07D463/00 in which the condensed system contains two hetero rings
    • C07D471/04Ortho-condensed systems

Definitions

  • DHODH dihydroorotate dehydrogenase
  • Acute myelogenous leukemia is a clonal disease of the blood and bone marrow resulting from mutations that occur in normal hematopoietic stem cells.
  • AML is a heterogenous disease in that it presents with a range of cytogenetic, morphological and immunophenotypic features, and is characterized by an accumulation of clonal, abnormal myeloid progenitor cells, known as myeloblasts.
  • AML represents an unmet medical need with >20,000 new cases per year in the US with 5-year overall survival below 30% (Stein ET et al., Health Qual Life Outcomes 16: 193, 2018). Differentiation therapy is considered an attractive approach to AML treatment based on the knowledge that differentiation and loss of stem cell self-renewal are coupled in normal cells.
  • Retinoic acid targets the promyelocytic leukemia protein (PML)-retinoic acid receptor- ⁇ (RAR- ⁇ ) fusion protein encoded by a t(15,17) chromosomal translocation.
  • PML-RAR specifically lifts the transcriptionally mediated differentiation block induced by the fusion protein and early clinical trials with single agent ATRA demonstrated complete hematologic remission in all treated patients (McCulloch D et al. Onco Targets Ther 2017; 10: 1585–1601; Nowak D et al. Blood 113: 3655, 2009).
  • DHODH dihydroorotate dehydrogenase
  • DHODH is a flavin mononucleotide (FMN) flavoprotein located in the inner mitochondrial membrane that catalyzes the oxidation of dihydroorotate to orotate, the fourth step in the de novo pyrimidine biosynthesis pathway. Inhibition of DHODH leads to decreased pyrimidine synthesis important precursors for nucleotide synthesis, but also glycoprotein and phospholipid biosynthesis (Reis RAG et al., Archives Biochem Biophysics 632: 175, 2017; Vyas VK et al., Mini Rev Med Chem 11: 1039, 2011).
  • FMN flavin mononucleotide
  • DHODH is a validated target for the treatment of autoimmune diseases with the FDA approved small molecule DHODH inhibitors leflunomide and teriflunomide for rheumatoid arthritis and multiple sclerosis, respectively (Lolli ML et al., Recent patents on Anti-Cancer Drug Discovery 13: 86, 2018). Since the first observation by Sykes et al.
  • DHODH inhibition drives AML differentiation in vitro, as evidenced by upregulation of the differentiation markers CD11b and CD14, and results in dose dependent anti-leukemic effects, decreased leukemic stem cells and prolonged survival in vivo, additional evidence emerged demonstrating that small molecule DHODH inhibitors mediate antiproliferative activity against AML cells with concomitant cell cycle arrest, upregulation of CD11b and CD14, and induction of apoptosis (Wu D et al.. Haematologica 103: 1472, 2018; Sainas S et al., J Med Chem 61: 6034, 2018; Cao L et al., Mol Cancer Ther, October 23rd Epub ahead of print).
  • Embodiments of the present invention relate to compounds, pharmaceutical compositions containing them, methods of making and purifying them, methods of using them as inhibitors of DHODH enzymatic activity and methods for using them in the treatment of a subject suffering from or diagnosed with a disease, disorder, or medical condition such as autoimmune or inflammatory disorders, or diseases such as cancer.
  • Embodiments of this invention include compounds of Formula (I), wherein R 1 is C 1-6 alkyl or C 1-6 haloalkyl; R b is C 1-6 alkyl substituted with one OH member; R 3 is H or halo; R 4 is selected from the group consisting of: wherein R e is selected from the group consisting of: H; halo; C 1-6 alkyl; C 1-6 alkyl substituted with one member selected from the group consisting of: OH, OCH 3 , and OCF 3 ; C 1-6 haloalkyl; C 1-6 haloalkyl substituted with one member selected from the group consisting of: OH, and OCH 3 ; and OC 1-6 alkyl; R f is selected from the group consisting of: H; halo; C 1-6 alkyl; C 1-6 alkyl substituted with one member selected from the group consisting of: OH, OCH 3 , and OCF 3 ; C 1-6 haloalkyl; C
  • the present invention further provides methods for treating or ameliorating a disease, syndrome, condition, or disorder in a subject, including a mammal and/or human in which the disease, syndrome, condition, or disorder is affected by the inhibition of DHODH enzymatic activity, including but not limited to, cancer and/or inflammatory or immunological diseases, using a compound of Formula (I) or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer thereof. Additional embodiments, features, and advantages of the invention will be apparent from the following detailed description and through practice of the invention. DETAILED DESCRIPTION OF THE INVENTION Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in art.
  • alkyl refers to a straight- or branched-chain alkyl group having from 1 to 8 carbon atoms in the chain.
  • alkyl groups include methyl (Me), ethyl (Et), n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl (tBu), pentyl, isopentyl, tert-pentyl, hexyl, isohexyl, and groups that in light of the ordinary skill in the art and the teachings provided herein would be considered equivalent to any one of the foregoing examples.
  • C 1-6 alkyl refers to straight- or branched-chain alkyl group having from 1 to 6 carbon atoms in the chain.
  • C 1-4 alkyl refers to straight- or branched-chain alkyl group having from 1 to 4 carbon atoms in the chain.
  • cycloalkyl refers to a saturated or partially saturated, monocyclic, fused polycyclic, or spiro polycyclic carbocycle having from 3 to 12 ring atoms per carbocycle.
  • C 3- 6 cycloalkyl refers to a carbocycle having from 3 to 6 ring atoms per carbocycle.
  • Illustrative examples of cycloalkyl groups include the following entities, in the form of properly bonded moieties:
  • halogen or “halo” represents chlorine, fluorine, bromine, or iodine.
  • haloalkyl refers to a straight- or branched-chain alkyl group having from 1 to 6 carbon atoms in the chain optionally substituting hydrogens with halogens.
  • C 1-6 haloalkyl refers to a straight- or branched-chain alkyl group having from 1 to 6 carbon atoms in the chain, optionally substituting hydrogens with halogens.
  • C 1-4 haloalkyl refers to a straight- or branched-chain alkyl group having from 1 to 4 carbon atoms in the chain, optionally substituting hydrogens with halogens.
  • haloalkyl groups include trifluoromethyl (CF 3 ), difluoromethyl (CF 2 H), monofluoromethyl (CH 2 F), pentafluoroethyl (CF 2 CF 3 ), tetrafluoroethyl (CHFCF 3 ), monofluoroethyl (CH 2 CH 2 F), trifluoroethyl (CH 2 CF 3 ), tetrafluorotrifluoromethylethyl (CF(CF 3 ) 2 ), and groups that in light of the ordinary skill in the art and the teachings provided herein would be considered equivalent to any one of the foregoing examples.
  • aryl refers to a monocyclic, aromatic carbocycle (ring structure having ring atoms that are all carbon) having 6 atoms per ring. (Carbon atoms in the aryl groups are sp2 hybridized.)
  • phenyl represents the following moiety:
  • heteroaryl refers to a monocyclic or fused bicyclic heterocycle (ring structure having ring atoms selected from carbon atoms and up to four heteroatoms selected from nitrogen, oxygen, and sulfur) having from 3 to 9 ring atoms per heterocycle.
  • heteroaryl groups include the following entities, in the form of properly bonded moieties: Those skilled in the art will recognize that the species of cycloalkyl, heteroaryl and aryl groups listed or illustrated above are not exhaustive, and that additional species within the scope of these defined terms may also be selected.
  • the term “variable point of attachment” means that a group is allowed to be attached at more than one alternative position in a structure. The attachment will always replace a hydrogen atom on one of the ring atoms. In other words, all permutations of bonding are represented by the single diagram, as shown in the illustrations below.
  • composition is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts.
  • the term “treat”, “treating”, or “treatment” of any disease, condition, syndrome or disorder refers, in one embodiment, to ameliorating the disease, condition, syndrome or disorder (i.e. slowing or arresting or reducing the development of the disease or at least one of the clinical symptoms thereof).
  • “treat”, “treating”, or “treatment” refers to alleviating or ameliorating at least one physiological or biochemical parameter associated with or causative of the disease, condition, syndrome or disorder, including those which may not be discernible by the patient.
  • “treat”, “treating”, or “treatment” refers to modulating the disease, condition, syndrome or disorder either physically (e.g. stabilization of a discernible symptom), physiologically, (e.g.
  • “treat”, “treating”, or “treatment” refers to preventing or delaying the onset or development or progression of the disease, condition, syndrome or disorder.
  • subject and “patient” are used interchangeably herein and may refer to an animal, preferably a mammal, most preferably a human.
  • active compound, pharmaceutical agent and active ingredient are used interchangeably to refer to a pharmaceutically active compound.
  • Other ingredients in a drug composition such as carriers, diluents or excipients, may be substantially or completely pharmaceutically inert.
  • a pharmaceutical composition may comprise the active ingredient in combination with one or more carriers and/or one or more excipients and/or one or more diluents.
  • the term “therapeutically effective amount” refers to an amount (e.g., of an active compound or pharmaceutical agent, such as a compound of the present invention), which elicits the biological or medicinal response in a tissue system, animal or human that is being sought by a researcher, veterinarian, medical doctor or other clinician, including reduction or inhibition of an enzyme or a protein activity, or ameliorating symptoms, alleviating conditions, slowing or delaying disease progression, or preventing a disease.
  • therapeutically effective amount may refer to an amount that, when administered to a particular subject, achieves a therapeutic effect by inhibiting, alleviating or curing a disease, condition, syndrome or disorder in the subject or by prophylactically inhibiting, preventing or delaying the onset of a disease, condition, syndrome or disorder, or symptom(s) thereof.
  • a therapeutically effective amount may be an amount which relieves to some extent one or more symptoms of a disease, condition, syndrome or disorder in a subject; and/or returns to normal either partially or completely one or more physiological or biochemical parameters associated with or causative of the disease, condition, syndrome or disorder; and/or reduces the likelihood of the onset of the disease, condition, syndrome or disorder, or symptom(s) thereof.
  • “Pharmaceutically acceptable” means that, which is useful in preparing a pharmaceutical composition that is generally safe, non-toxic and neither biologically nor otherwise undesirable and includes that which is acceptable for veterinary as well as human pharmaceutical use.
  • a “pharmaceutically acceptable salt” is intended to mean a salt of an acid or base of a compound represented by Formula (I) (as well as compounds of Formula (IA), (IB), and (IC)) that is non-toxic, biologically tolerable, or otherwise biologically suitable for administration to the subject. See, generally, S.M. Berge, et al., “Pharmaceutical Salts”, J. Pharm.
  • Preferred pharmaceutically acceptable salts are those that are pharmacologically effective and suitable for contact with the tissues of patients without undue toxicity, irritation, or allergic response.
  • Non-limiting examples of pharmaceutically acceptable salts include sulfates, pyrosulfates, bisulfates, sulfites, bisulfites, phosphates, monohydrogen-phosphates, dihydrogenphosphates, metaphosphates, pyrophosphates, chlorides, bromides, iodides, acetates, propionates, decanoates, caprylates, acrylates, formates, isobutyrates, caproates, heptanoates, propiolates, oxalates, malonates, succinates, suberates, sebacates, fumarates, maleates, butyne- 1,4-dioates, hexyne-1,6-dioates, benzoates, chlorobenzoates, methylbenzoates, dinitrobenzoates, hydroxybenzoates, methoxybenzoates, phthalates, sulfonates, xylenesulfonates, phenylacetates
  • a compound of Formula (I) may possess a sufficiently acidic group, a sufficiently basic group, or both types of functional groups, and accordingly react with a number of inorganic or organic bases, and inorganic and organic acids, to form a pharmaceutically acceptable salt.
  • Compounds of Formula (I) may contain at least one nitrogen of basic character, so desired pharmaceutically acceptable salts may be prepared by any suitable method available in the art, for example, treatment of the free base with an inorganic acid, such as hydrochloric acid, hydrobromic acid, sulfuric acid, sulfamic acid, nitric acid, boric acid, phosphoric acid, and the like, or with an organic acid, such as acetic acid, phenylacetic acid, propionic acid, stearic acid, lactic acid, ascorbic acid, maleic acid, hydroxymaleic acid, isethionic acid, succinic acid, valeric acid, fumaric acid, malonic acid, pyruvic acid, oxalic acid, glycolic acid, salicylic
  • Compounds of Formula (I) may contain a carboxylic acid moiety, a desired pharmaceutically acceptable salt may be prepared by any suitable method, for example, treatment of the free acid with an inorganic or organic base, such as an amine (primary, secondary or tertiary), an alkali metal hydroxide, alkaline earth metal hydroxide, any compatible mixture of bases such as those given as examples herein, and any other base and mixture thereof that are regarded as equivalents or acceptable substitutes in light of the ordinary level of skill in this technology.
  • an inorganic or organic base such as an amine (primary, secondary or tertiary), an alkali metal hydroxide, alkaline earth metal hydroxide, any compatible mixture of bases such as those given as examples herein, and any other base and mixture thereof that are regarded as equivalents or acceptable substitutes in light of the ordinary level of skill in this technology.
  • Suitable salts include organic salts derived from amino acids, such as glycine and arginine, ammonia, carbonates, bicarbonates, primary, secondary, and tertiary amines, and cyclic amines, such as benzylamines, pyrrolidines, piperidine, morpholine, piperazine, N-methyl-glucamine and tromethamine and inorganic salts derived from sodium, calcium, potassium, magnesium, manganese, iron, copper, zinc, aluminum, and lithium.
  • amino acids such as glycine and arginine
  • ammonia carbonates
  • bicarbonates primary, secondary, and tertiary amines
  • cyclic amines such as benzylamines, pyrrolidines, piperidine, morpholine, piperazine, N-methyl-glucamine and tromethamine
  • inorganic salts derived from sodium, calcium, potassium, magnesium, manganese, iron, copper, zinc, aluminum, and lithium.
  • any formula given herein may have asymmetric centers and therefore exist in different enantiomeric forms. All optical isomers and stereoisomers of the compounds of the general formula, and mixtures thereof, are considered within the scope of such formula.
  • the compounds of this invention may possess one or more asymmetric centers; such compounds can therefore be produced as individual (R)- or (S)-stereoisomers or as mixtures thereof.
  • any formula given herein is intended to represent a racemate, one or more of its enantiomeric forms, one or more of its diastereomeric forms, and mixtures thereof.
  • any formula given herein is intended to refer also to any one of: hydrates, solvates, polymorphs and of such compounds, and mixtures thereof, even if such forms are not listed explicitly.
  • the term “R” at a stereocenter designates that the stereocenter is purely of the R- configuration as defined in the art; likewise, the term “S” means that the stereocenter is purely of the S-configuration.
  • the term “RS” refers to a stereocenter that exists as a mixture of the R- and S-configurations.
  • Compounds containing one stereocenter drawn without a stereo bond designation are a mixture of 2 enantiomers.
  • Compounds containing 2 stereocenters both drawn without stereo bond designations are a mixture of 4 diastereomers.
  • references to a compound herein stands for a reference to any one of: (a) the recited form of such compound, and (b) any of the forms of such compound in the medium in which the compound is being considered when named.
  • reference herein to a compound such as R-COOH encompasses reference to any one of: for example, R-COOH(s), R-COOH(sol), and R-COO-(sol).
  • R-COOH(s) refers to the solid compound, as it could be for example in a tablet or some other solid pharmaceutical composition or preparation
  • R- COOH(sol) refers to the undissociated form of the compound in a solvent
  • R-COO-(sol) refers to the dissociated form of the compound in a solvent, such as the dissociated form of the compound in an aqueous environment, whether such dissociated form derives from R-COOH, from a salt thereof, or from any other entity that yields R-COO- upon dissociation in the medium being considered.
  • an expression such as “exposing an entity to compound of formula R-COOH” refers to the exposure of such entity to the form, or forms, of the compound R-COOH that exists, or exist, in the medium in which such exposure takes place.
  • an expression such as “reacting an entity with a compound of formula R-COOH” refers to the reacting of (a) such entity in the chemically relevant form, or forms, of such entity that exists, or exist, in the medium in which such reacting takes place, with (b) the chemically relevant form, or forms, of the compound R-COOH that exists, or exist, in the medium in which such reacting takes place.
  • Isotopically labeled compounds have structures depicted by the formulas given herein except that one or more atoms are replaced by an atom having a selected atomic mass or mass number in an enriched form.
  • isotopes that can be incorporated into compounds of the invention in a form that exceeds natural abundances include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, fluorine, chlorine, and iodine, such as 2 H (or chemical symbol D), 3 H (or chemical symbol T), 11 C, 13 C, 14 C, 15 N, 18 O, 17 O, 31 P, 32 P, 35 S, 18 F, 36 Cl, and 125 I, respectively.
  • Such isotopically labelled compounds are useful in metabolic studies (preferably with 14 C), reaction kinetic studies (with, for example 2 H or 3 H), detection or imaging techniques [such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT)] including drug or substrate tissue distribution assays, or in radioactive treatment of patients.
  • PET positron emission tomography
  • SPECT single-photon emission computed tomography
  • an 18 F or 11 C labeled compound may be particularly preferred for PET or SPECT studies.
  • substitution with heavier isotopes such as deuterium (i.e., 2 H, or D) may afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements.
  • Isotopically labeled compounds of this invention can generally be prepared by carrying out the procedures disclosed in the schemes or in the examples and preparations described below by substituting a readily available isotopically labeled reagent for a non-isotopically labeled reagent.
  • Cn-m alkyl refers to an aliphatic chain, whether straight or branched, with a total number N of carbon members in the chain that satisfies n ⁇ N ⁇ m, with m > n.
  • the specific individual substituent assignment to each of such groups is meant to be independently made with respect to the specific individual substituent assignments to the remaining groups.
  • each of groups Q and R can be H or F
  • the choice of H or F for Q is made independently of the choice of H or F for R, so the choice of assignment for Q does not determine or condition the choice of assignment for R, or vice-versa, unless it is expressly indicated otherwise.
  • Illustrative claim recitation in this regard would read as “each of Q and R is independently H or F”, or “each of Q and R is independently selected from the group consisting of H and F”.
  • a zwitterionic compound would be encompassed herein by referring to a compound that is known to form a zwitterion, even if it is not explicitly named in its zwitterionic form.
  • zwitterion zwitterions
  • zwitterionic compound(s) are standard IUPAC-endorsed names that are well known and part of standard sets of defined scientific names.
  • the name zwitterion is assigned the name identification CHEBI:27369 by the Chemical Entities of Biological Interest (ChEBI) dictionary of molecular entities.
  • a zwitterion or zwitterionic compound is a neutral compound that has formal unit charges of opposite sign. Sometimes these compounds are referred to by the term “inner salts”.
  • Other sources refer to these compounds as “dipolar ions”, although the latter term is regarded by still other sources as a misnomer.
  • aminoethanoic acid (the amino acid glycine) has the formula H 2 NCH 2 COOH, and it exists in some media (in this case in neutral media) in the form of the zwitterion + H 3 NCH 2 COO-.
  • Zwitterions, zwitterionic compounds, inner salts and dipolar ions in the known and well- established meanings of these terms are within the scope of this invention, as would in any case be so appreciated by those of ordinary skill in the art. Because there is no need to name each and every embodiment that would be recognized by those of ordinary skill in the art, no structures of the zwitterionic compounds that are associated with the compounds of this invention are given explicitly herein. They are, however, part of the embodiments of this invention.
  • substituent S example is one of S 1 , S 2 , and S 3
  • this listing refers to embodiments of this invention for which S example is S 1 ; S example is S 2 ; S example is S 3 ; S example is one of S 1 and S 2 ; S example is one of S 1 and S 3 ; S example is one of S 2 and S 3 ; S example is one of S 1 , S 2 and S 3 ; and S example is any equivalent of each one of these choices.
  • the shorter terminology “S example is one of S 1 , S 2 , and S 3 ” is accordingly used herein for the sake of brevity, but not by way of limitation.
  • C i -C j refers independently to embodiments that have one carbon member ( C 1 ), embodiments that have two carbon members (C 2 ), and embodiments that have three carbon members (C 3 ).
  • Embodiments of this invention include compounds of Formula (I), wherein R 1 is C 1-6 alkyl or C 1-6 haloalkyl; R a is C 1-6 alkyl; R b is C 1-6 alkyl substituted with one OH member; R 3 is H or halo; wherein R e is selected from the group consisting of: H; halo; C 1-6 alkyl; C 1-6 alkyl substituted with one member selected from the group consisting of: OH, OCH 3 , and OCF 3 ; C 1-6 haloalkyl; C 1-6 haloalkyl substituted with one member selected from the group consisting of: OH, and OCH 3 ; and OC 1-6 alkyl; R f is selected from the group consisting of: H; halo; C 1-6 alkyl; C 1-6 alkyl substituted with one member selected from the group consisting of: OH, OCH 3 , and OCF 3 ; C 1-6 haloalkyl; C
  • An additional embodiment of the invention is a compound of Formula (I) wherein R 1 is C1-4alkyl.
  • An additional embodiment of the invention is a compound of Formula (I) wherein R 1 is CH(CH 3 ) 2 .
  • An additional embodiment of the invention is a compound of Formula (I) wherein R 2 is
  • An additional embodiment of the invention is a compound of Formula (I) wherein R 2 is
  • An additional embodiment of the invention is a compound of Formula (I) wherein R 3 is F.
  • An additional embodiment of the invention is a compound of Formula (I) wherein R 4 is An additional embodiment of the invention is a compound of Formula (I) wherein R 4 is An additional embodiment of the invention is a compound of Formula (I) wherein R 4 is An additional embodiment of the current invention is a compound selected from the compounds shown below in Table 1, and pharmaceutically acceptable salts, isotopes, N-oxides, solvates, and stereoisomers thereof: Table 1 Example # Compound Name
  • compositions comprising compounds of Formula (I) and at least one pharmaceutically acceptable carrier, pharmaceutically acceptable excipient, and/or pharmaceutically acceptable diluent.
  • the compounds of Formula (I) may be admixed with any suitable binder(s), lubricant(s), suspending agent(s), coating agent(s), solubilizing agent(s), and combinations thereof.
  • An embodiment of the invention relates to a pharmaceutical composition comprising an effective amount of at least one compound selected from compounds of Formula (I), and pharmaceutically acceptable salts, isotopes, N-oxides, solvates, and stereoisomers thereof, in accordance with any embodiment described herein; and at least one pharmaceutically acceptable excipient.
  • An additional embodiment of the invention is a pharmaceutical composition
  • a pharmaceutical composition comprising: (A) an effective amount of at least one compound selected from compounds of Formula (I) R 1 R 2 wherein R 1 is C 1-6 alkyl or C 1-6 haloalkyl; R 2 i R 3 is H or halo; R 4 is selected from the group consisting of: wherein R e is selected from the group consisting of: H; halo; C 1-6 alkyl; C 1-6 alkyl substituted with one member selected from the group consisting of: OH, OCH 3 , and OCF 3 ; C 1-6 haloalkyl; C 1-6 haloalkyl substituted with one member selected from the group consisting of: OH, and OCH 3 ; and OC 1-6 alkyl; R f is selected from the group consisting of: H; halo; C 1-6 alkyl; C 1-6 alkyl substituted with one member selected from the group consisting of: OH, OCH 3 , and OCF
  • An additional embodiment of the invention is a pharmaceutical composition
  • a pharmaceutical composition comprising an effective amount of a compound shown in Table 1 (e.g., a compound selected from Examples 1-9), or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer of the compound of Table 1, a pharmaceutically acceptable prodrug of the compound of Table 1, or a pharmaceutically active metabolite of the compound of Table 1; and at least one pharmaceutically acceptable excipient.
  • Solid oral dosage forms such as, tablets or capsules, containing one or more compounds of the present invention may be administered in at least one dosage form at a time, as appropriate. It is also possible to administer the compounds in sustained release formulations.
  • Additional oral forms in which the present inventive compounds may be administered include elixirs, solutions, syrups, and suspensions; each optionally containing flavoring agents and coloring agents.
  • one or more compounds of Formula (I) can be administered by inhalation (intratracheal or intranasal) or in the form of a suppository or pessary, or they may be applied topically in the form of a lotion, solution, cream, ointment or dusting powder.
  • they can be incorporated into a cream comprising, consisting of, and/or consisting essentially of an aqueous emulsion of polyethylene glycols or liquid paraffin.
  • compositions of the present invention can also be injected parenterally, for example, intracavernosally, intravenously, intramuscularly, subcutaneously, intradermally, or intrathecally.
  • compositions will also include at least one of a suitable carrier, a suitable excipient, and a suitable diluent.
  • a suitable carrier for parenteral administration, the pharmaceutical compositions of the present invention are best used in the form of a sterile aqueous solution that may contain other substances, for example, enough salts and monosaccharides to make the solution isotonic with blood.
  • the pharmaceutical compositions of the present invention may be administered in the form of tablets or lozenges, which can be formulated in a conventional manner.
  • compositions containing at least one of the compounds of Formula (I) as the active ingredient can be prepared by mixing the compound(s) with a pharmaceutically acceptable carrier, a pharmaceutically acceptable diluent, and/or a pharmaceutically acceptable excipient according to conventional pharmaceutical compounding techniques.
  • a pharmaceutically acceptable carrier e.g., benzyl alcohol, benzyl ether, benzyl ether, benzyl ether, benzyl, sulfonyl, sulfonyl, adiluent, and/or a pharmaceutically acceptable excipient according to conventional pharmaceutical compounding techniques.
  • the carrier, excipient, and diluent may take a wide variety of forms depending upon the desired route of administration (e.g., oral, parenteral, etc.).
  • suitable carriers, excipients and diluents include water, glycols, oils, alcohols, flavoring agents, preservatives, stabilizers, coloring agents and the like;
  • suitable carriers, excipients and diluents include starches, sugars, diluents, granulating agents, lubricants, binders, disintegrating agents and the like.
  • Solid oral preparations also may be optionally coated with substances such as, sugars, or be enterically coated so as to modulate the major site of absorption and disintegration.
  • the carrier, excipient and diluent will usually include sterile water, and other ingredients may be added to increase solubility and preservation of the composition.
  • injectable suspensions or solutions may also be prepared utilizing aqueous carriers along with appropriate additives such as, solubilizers and preservatives.
  • a therapeutically effective amount of a compound of Formula (I) or a pharmaceutical composition thereof may comprise a dose range from about 0.1 mg to about 3000 mg, or any particular amount or range therein, in particular from about 1 mg to about 1000 mg, or any particular amount or range therein, of active ingredient in a regimen of about 1 to about (4x) per day for an average (70 kg) human; although, it is apparent to one skilled in the art that the therapeutically effective amount for a compound of Formula (I) will vary as will the diseases, syndromes, conditions, and disorders being treated.
  • An embodiment of the present invention is directed to a pharmaceutical composition for oral administration, comprising a compound of Formula (I) in an amount of from about 1 mg to about 500 mg.
  • a compound of Formula (I) may be administered in a single daily dose, or the total daily dosage may be administered in divided doses of two, three and (4x) daily.
  • Optimal dosages of a compound of Formula (I) to be administered may be readily determined and will vary with the particular compound used, the mode of administration, the strength of the preparation, and the advancement of the disease, syndrome, condition or disorder.
  • factors associated with the particular subject being treated including subject gender, age, weight, diet and time of administration, will result in the need to adjust the dose to achieve an appropriate therapeutic level and desired therapeutic effect.
  • the above dosages are thus exemplary of the average case. There can be, of course, individual instances wherein higher or lower dosage ranges are merited, and such are within the scope of this invention.
  • Compounds of Formula (I) may be administered in any of the foregoing compositions and dosage regimens or by means of those compositions and dosage regimens established in the art whenever use of a compound of Formula (I) is administered to a subject in need thereof.
  • one or more compounds of Formula (I) are useful in methods for treating, ameliorating and / or preventing a disease, a syndrome, a condition or a disorder that is affected by the inhibition of DHODH enzymatic activity.
  • An additional embodiment of the invention relates to the use of compounds of Formula (I), e.g., by inhibiting dihydroorotate oxygenase enzyme activity, in treating disorders like inflammatory disorders, autoimmune disorders, or cancer; or pharmaceutically acceptable salts, isotopes, N-oxides, solvates, or stereoisomers thereof.
  • the present invention provides a method for inhibiting or altering Dihydroorotate Dehydrogenase (DHODH) enzymatic activity, the method comprising contacting DHODH with any compound of Formula (I), aspect or embodiment disclosed herein, thereby inhibiting or otherwise altering DHODH enzymatic activity.
  • DHODH Dihydroorotate Dehydrogenase
  • An additional embodiment of the present invention provides methods for treating diseases, disorders, or medical conditions mediated or otherwise affected by dihydroorotate dehydrogenase (DHODH) enzyme activity comprising administering a compound of Formula (I) to a subject in need thereof.
  • DHODH inhibitor may refer to an agent that inhibits or reduces DHODH activity.
  • the term “therapeutically effective amount” refers to the amount of a compound of the present invention that, when administered to a subject, is effective to (1) at least partially alleviate, inhibit, prevent, and/ or ameliorate a condition, or a disorder or a disease (i) mediated by DHODH enzymatic activity; or (ii) associated with DHODH enzymatic activity; or (iii) characterized by activity (normal or abnormal) of DHODH enzyme; or (2) reduce or inhibit the activity of DHODH enzyme; or (3) reduce or inhibit the expression of DHODH; or (4) modify the protein levels of DHODH.
  • DHODH inhibitors are believed to act by inhibiting nucleic acid synthesis, cell cycle arrest or altering post-translational glycosylation of proteins involved in regulating myeloid differentiation within progenitor tumor cells.
  • An additional embodiment of the invention is a method of treating a subject suffering from or diagnosed with a disease, disorder, or medical condition mediated or otherwise affected by DHODH enzymatic activity, comprising administering to a subject in need of such treatment an effective amount of at least one compound selected from: compounds of Formula (I), (such as a compound of Table 1), enantiomers and diastereomers of the compounds of Formula (I) (such as a compound of Table 1), isotopic variations of the compounds of Formula (I) (such as a compound of Table 1), and pharmaceutically acceptable salts of all of the foregoing.
  • compounds of Formula (I) such as a compound of Table 1
  • enantiomers and diastereomers of the compounds of Formula (I) such as a compound of Table 1
  • a method of treating a subject suffering from or diagnosed with a disease, disorder, or medical condition, such as cancer comprises administering to the subject an effective amount of at least one compound selected from: compounds of Formula (I), (such as a compound of Table 1), and pharmaceutically acceptable salts of all the foregoing (e.g., by inhibiting or otherwise altering dihydroorotate oxygenase enzyme activity in the subject).
  • compounds of Formula (I) such as a compound of Table 1
  • pharmaceutically acceptable salts of all the foregoing e.g., by inhibiting or otherwise altering dihydroorotate oxygenase enzyme activity in the subject.
  • inhibitors of DHODH of the present invention may be used for the treatment of immunological diseases including, but not limited to, autoimmune and inflammatory disorders, e.g.
  • arthritis inflammatory bowel disease, gastritis, ankylosing spondylitis, ulcerative colitis, pancreatitis, Crohn’s disease, celiac disease, multiple sclerosis, systemic lupus erythematosus, lupus nephritis, rheumatic fever, gout, organ or transplant rejection, chronic allograft rejection, acute or chronic graft-versus-host disease, dermatitis including atopic, dermatomyositis, psoriasis, Behcet’s diseases, uveitis, myasthenia gravis, Grave’s disease, Hashimoto thyroiditis, Sjogren’s syndrome, blistering disorders, antibody- mediated vasculitis syndromes, immune-complex vasculitides, allergic disorders, asthma, bronchitis, chronic obstructive pulmonary disease (COPD), cystic fibrosis, pneumonia, pulmonary diseases including edema, embolism, fibrosis,
  • the term “affect” or “affected” when referring to a disease, disorder, or medical condition that is affected by the inhibition or alteration of DHODH enzymatic activity) includes a reduction in the frequency and / or severity of one or more symptoms or manifestations of said disease, syndrome, condition or disorder; and / or includes the prevention of the development of one or more symptoms or manifestations of said disease, syndrome, condition or disorder or the development of the disease, condition, syndrome or disorder.
  • An additional embodiment of the invention provides a method of treatment of cancer comprising administering to a subject in need thereof, a therapeutically effective amount of a compound of Formula (I), or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer thereof.
  • the cancer is selected from but not limited to, lymphomas, leukemias, carcinomas, and sarcomas.
  • An additional embodiment of the invention provides the use of a compound of Formula (I), or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer thereof, for the treatment of one or more cancer types.
  • the uses and methods of treatment described herein are directed to the treatment of cancer, wherein the cancer is selected from but not limited to: leukemias including but not limited to acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), (acute) T-cell leukemia, acute monocytic leukemia, acute promyelocytic leukemia (APL), bisphenotypic B myelomonocytic leukemia, chronic myeloid leukemia (CML), chronic myelomonocytic leukemia (CMML), large granular lymphocytic leukemia, plasma cell leukemia, and also myelodysplastic syndrome (MDS), which can develop into an acute myeloid leukemia, lymphomas including but not limited to AIDS-related lymphoma, Hodgkin lymphoma, non-Hodgkin's lymphoma (NHL), T-non-Hodgkin lymphoma (T-NHL), subtype
  • ALL acute lymph
  • cancers that may benefit from a treatment with inhibitors of DHODH of the present invention include, but are not limited to, lymphomas, leukemias, carcinomas, and sarcomas, e.g. non-Hodgkin’s lymphoma, diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), follicular lymphoma (FL), marginal zone lymphoma, T-cell lymphoma, Hodgkin’s lymphoma, Burkitt’s lymphoma, multiple myeloma, brain (gliomas), glioblastomas, breast cancer, colorectal/colon cancer, prostate cancer, lung cancer including non-small-cell, gastric cancer, endometrial cancer, melanoma, pancreatic cancer, liver cancer, kidney cancer, squamous cell carcinoma, ovarian cancer, sarcoma, osteosarcoma, thyroid cancer, bladder cancer, head & neck cancer, testicular
  • the compounds of the present invention may be employed in combination with one or more other medicinal agents, more particularly with one or more anti-cancer agents, e.g. chemotherapeutic, anti-proliferative or immunomodulating agents, or with adjuvants in cancer therapy, e.g. immunosuppressive or anti- inflammatory agents.
  • anti-cancer agents e.g. chemotherapeutic, anti-proliferative or immunomodulating agents, or with adjuvants in cancer therapy, e.g. immunosuppressive or anti- inflammatory agents.
  • Additional non-limiting examples of anti-cancer agents that may be administered in combination with a compound of the present invention include biologic compounds, such as monoclonal antibodies (e.g., that mediate effector function upon binding to cancer cell-associated antigens, or block interaction of a receptor expressed on cancer cells with a soluble or cell bound ligand), bispecific antibodies that mediate immune cell redirection, etc.
  • a method of treating cancer comprises administering an effective amount of a compound of the present invention (e.g., selected from compounds of Formula (I), such as a compound shown in Table 1, pharmaceutically acceptable salts, isotopes, N-oxides, solvates, and stereoisomers thereof) and an effective amount of one or more additional anti- cancer agents, wherein the method comprises administering the compound of the present invention and the additional anti-cancer agent(s) either simultaneously (e.g., as part of the same pharmaceutical composition) or sequentially.
  • a compound of the present invention e.g., selected from compounds of Formula (I), such as a compound shown in Table 1, pharmaceutically acceptable salts, isotopes, N-oxides, solvates, and stereoisomers thereof
  • a pharmaceutical composition comprises an effective amount of a compound of the present invention (e.g., selected from compounds of Formula (I), such as a compound shown in Table 1, pharmaceutically acceptable salts, isotopes, N-oxides, solvates, and stereoisomers thereof), an effective amount of one or more additional anti-cancer agents, and optionally one or more excipients.
  • a compound of Formula (I) e.g., selected from compounds of Formula (I), such as a compound shown in Table 1, pharmaceutically acceptable salts, isotopes, N-oxides, solvates, and stereoisomers thereof
  • An additional embodiment of the invention provides the use of a compound of Formula (I), or pharmaceutically acceptable salts, isotopes, N-oxides, solvates, or stereoisomers thereof, as part of chemotherapeutic regimens for the treatment of cancers, lymphomas and leukemias alone or in combination with classic antitumoral compounds well known by the one skilled in the art.
  • Reactions may be performed between the melting point and the reflux temperature of the solvent, and preferably between 0 °C and the reflux temperature of the solvent. Reactions may be heated employing conventional heating or microwave heating. Reactions may also be conducted in sealed pressure vessels above the normal reflux temperature of the solvent. Abbreviations used in the instant specification, particularly the schemes and examples, are as follows in Table 2: Table 2.
  • a 1,2,4-triazol-5(4H)-one compound of formula (II), where PG is Bn is prepared from ethyl 2-(benzyloxy)acetate in three steps.
  • 2- (benzyloxy)acetohydrazide is prepared by the reaction of ethyl 2-(benzyloxy)acetate with hydrazine hydrate, in a suitable solvent such as EtOH, and the like; at temperatures ranging from 70-85 °C.
  • SCHEME 2 According to SCHEME 2, a compound of formula (III), where Y is CH or N, and R a is C 1-6 alkyl; is reacted with a Grignard reagent such as MeMgBr, in a suitable solvent such as THF, ether, or a mixture thereof; and the like; at temperatures of about 0 °C, for period of about 2-6 hrs; to provide a compound of formula (IV).
  • a Grignard reagent such as MeMgBr
  • a compound of formula (IV) is reacted with a source of tributyltin radical such as hexa ⁇ n ⁇ butylditin; a palladium catalyst such as Pd(PPh 3 ) 2 Cl 2 , and the like; in a suitable solvent such as toluene; at a temperature of about 100 °C; for a period of 12-18 h; to provide a compound of formula (V).
  • a source of tributyltin radical such as hexa ⁇ n ⁇ butylditin
  • a palladium catalyst such as Pd(PPh 3 ) 2 Cl 2 , and the like
  • a suitable solvent such as toluene
  • SCHEME 3 According to SCHEME 3, a commercially available or synthetically accessible compound of formula (VI), where R 4 is as described in claim 1, is reacted in a transition-metal- catalyzed borylation reaction employing conditions known to one skilled in the art.
  • an aryl or heteroaryl halide compound of formula (VI) where R 4 is as described in claim 1 is reacted in cross-coupling reaction of bis(pinacolato)diboron (B 2 pin 2 ); a palladium catalyst such as Pd(dppf)Cl 2 , and the like; a base such as KOAc, NaOAc, and the like; in a suitable solvent, such as 1,4-dioxane, DMSO, toluene, and the like; at temperatures of about 100 °C, for a period of 16-24 h; to provide a compound of formula (VII).
  • SCHEME 4 According to SCHEME 4, 2-chloro-5-fluoro-4-iodopyridine; and triazolone of formula (II), where R a is C 1-6 alkyl, and PG is a protecting group such as benzyl, para-methoxy benzyl, TBDPS, TIPS, TBS, and the like, are reacted employing copper catalyzed arylation conditions to provide a compound of formula (VIII).
  • a Cu(I) or Cu(II) salt such as Cu
  • a transition metal catalysts such as Pd(PPh 3 ) 2 Cl 2 ,
  • Piperidine-catalyzed Knoevenagel condensation reaction between diethyl malonate and a compound of formula (IX) affords a compound of formula (X).
  • SCHEME 5 According to SCHEME 5, 2-chloro-5-fluoro-4-iodopyridine is reacted in a Pd-catalyzed arylation reaction with diphenyl methanimine; employing a palladium catalyst such as Pd 2 (dba) 3 , and the like; a suitable ligand such as 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (XantPhos), and the like; a base such as Cs 2 CO 3 , LHMDS, NaOtBu, K 3 PO 4 , and the like; in a suitable solvent such as toluene, THF, DMF, dioxane, toluene, or a mixture thereof; at temperatures ranging from 80-150 oC, employing microwave or conventional heating; for a period of 0.5 h to 18 h; to provide 2-chloro-N-(diphenylmethylene)-5-fluoropyridin-4-amine.
  • a compound of formula (XIII) is reacted under diazotization conditions known to one skilled in the art.
  • a compound of formula (XIII) is reacted with tert-butyl nitrite or other nitrite reagents; and CuBr2; at temperatures of about 70 °C; for a period of about 6 h; to provide a compound of formula (XIV), where R 1 is CH(CH 3 ) 2 .
  • a compound of formula (XIV) is reacted with a commercially available or synthetically accessible organostannane compound of formula (V), where Y is CH or N, and R a is C 1-6 alkyl, using a palladium catalyst such as Pd(PPh 3 ) 3 Cl 2 , Pd(dppf)Cl 2 , and the like; in a suitable solvent such as 1,4-dioxane, toluene, and the like; at refluxing temperatures; to provide a compound of formula (XV).
  • a palladium catalyst such as Pd(PPh 3 ) 3 Cl 2 , Pd(dppf)Cl 2 , and the like
  • a suitable solvent such as 1,4-dioxane, toluene, and the like
  • SCHEME 9 According to SCHEME 9, halogenation of a compound of formula (XVI) is achieved employing a brominating agent such as Br 2 , in a suitable solvent such as pyridine, at 100 °C, for a period of 2 hours, to afford a compound of formula (XVII), where HAL is Br.
  • a compound of formula (XVII); is reacted under Suzuki coupling conditions known to one skilled in the art with a commercially available or synthetically accessible suitably substituted compound of formula (VII), to provide a compound of Formula (I).
  • SCHEME 10 According to SCHEME 10, a compound of formula (XI) is hydrolyzed using conditions known to one skilled in the art.
  • a compound of formula (XIX) and a compound of formula (VII) are treated with XPhos Pd G3 and Cs 2 CO 3 in a mixture of 1,4-dioxane and water at 100 °C for a period of 1 h.
  • XPhos Pd G3 and Cs 2 CO 3 in a mixture of 1,4-dioxane and water at 100 °C for a period of 1 h.
  • Subsequent deprotection employing established methodologies, such as those described in T. W. Greene and P. G. M. Wuts, “Protective Groups in Organic Synthesis,” 3 ed., John Wiley & Sons, 1999), provides a compound of Formula (I).
  • compound of formula (XX), where R 3 is F, R a is C 1-6 alkyl and PG is Bn, is deprotected employing conditions known to one skilled in the art, preferably with BCl 3 in a suitable solvent such as DCM, and the like.
  • Compounds of Formula (I) may be converted to their corresponding salts using methods known to one of ordinary skill in the art.
  • an amine of Formula (I) is treated with trifluoroacetic acid, HCl, or citric acid in a solvent such as Et 2 O, CH 2 Cl 2 , THF, MeOH, chloroform, or isopropanol to provide the corresponding salt form.
  • Crystalline forms of pharmaceutically acceptable salts of compounds of Formula (I) may be obtained in crystalline form by recrystallization from polar solvents (including mixtures of polar solvents and aqueous mixtures of polar solvents) or from non-polar solvents (including mixtures of non-polar solvents).
  • polar solvents including mixtures of polar solvents and aqueous mixtures of polar solvents
  • non-polar solvents including mixtures of non-polar solvents.
  • Compounds prepared according to the schemes described above may be obtained as single forms, such as single enantiomers, by form-specific synthesis, or by resolution. Compounds prepared according to the schemes above may alternately be obtained as mixtures of various forms, such as racemic (1:1) or non-racemic (not 1:1) mixtures. Where racemic and non-racemic mixtures of enantiomers are obtained, single enantiomers may be isolated using conventional separation methods known to one of ordinary skill in the art, such as chiral chromatography, recrystallization, diastereomeric salt formation, derivatization into diastereomeric adducts, biotransformation, or enzymatic transformation.
  • Normal-phase silica gel chromatography was performed on silica gel (SiO 2 ) using prepacked cartridges.
  • Preparative reverse-phase high performance liquid chromatography was performed on either:
  • Preparative supercritical fluid high performance liquid chromatography (SFC) was performed either on a Thar 80 Prep-SFC system, or Waters 80Q Prep-SFC system from Waters.
  • the ABPR was set to 100bar to keep the CO 2 in SF conditions, and the flow rate may verify according to the compound characteristics, with a flow rate ranging from 50g/min to 70g/min.
  • MS Mass spectra
  • MS-2020 MSD MSD
  • Agilent 1200 ⁇ G6110A MSD using electrospray ionization (ESI) in positive mode unless otherwise indicated.
  • ESI electrospray ionization
  • Calculated (calcd.) mass corresponds to the exact mass.
  • Nuclear magnetic resonance (NMR) spectra were obtained on Bruker model AVIII 400 spectrometers.
  • Step B 2-(1-Methyl-4-(tributylstannyl)-1H-imidazol-2-yl)propan-2-ol.
  • 2-(4- bromo-1-methyl-1H-imidazol-2-yl)propan-2-ol 500 mg, 2.2 mmol
  • Pd(Ph 3 P) 2 Cl 2 155 mg, 221 ⁇ mol
  • 1,1,1,2,2,2-hexabutyldistannane (2.94 g, 5.1 mmol). Then the resulting mixture was stirred at 100 °C for 16 hours under N 2 .
  • Step B 3-((Benzyloxy)methyl)-4-ethyl-1H-1,2,4-triazol-5(4H)-one.
  • 2- (benzyloxy)acetohydrazide 52 g, 288 mmol
  • H 2 O 500 mL
  • isocyanatoethane 25.1 g, 346 mmol, 27.9 mL
  • the mixture was stirred at 25°C for 12 hr.
  • H 2 O (20 mL)
  • an aqueous solution 120 mL
  • NaOH 57.7 g, 1.44 mol
  • Step D Ethyl 8-((diphenylmethylene)amino)-7-fluoro-1-isopropyl-4-oxo-4H-quinolizine-3- carboxylate.
  • diethyl 2-(2-(4-((diphenylmethylene)amino)-5-fluoropyridin-2-yl)- 3-methyl butylidene)malonate 29.8 g, 45.7 mmol
  • Et 3 N 76.2 mL, 548 mmol
  • Step A Ethyl 7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1- isopropyl-4-oxo-4H-quinolizine-3-carboxylate and 7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1- methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-4-oxo-4H-quinolizine-3-carboxylic acid.
  • Lithium 7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl- 4-oxo-4H-quinolizine-3-carboxylate To a mixture of ethyl 7-fluoro-8-(2-(2-hydroxypropan-2- yl)-1-methyl-1H-imidazol-4-yl)-1-iso propyl-4-oxo-4H-quinolizine-3-carboxylate (100 mg, 205 ⁇ mol) in MeOH/THF (v/v, 1/1, 3 mL) was added LiOH.H 2 O (104 mg, 2.5 mmol) in H 2 O (1.5 mL).
  • Example 1 7-Fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-3- (o-tolyl)-4H-quinolizin-4-one.
  • the yellow solid was purified by preparative reversed phase HPLC (Stationary phase: Boston Prime C18, 5 ⁇ m, 150 ⁇ 30 mm ; Mobile phase: water (0.05% NH 3 H 2 O + 10 mM NH 4 HCO 3 ) (A) - MeCN (B), gradient elution: 47 - 77% B in A over 8 min, flow rate: 30 mL/min) to give the title compound (27 mg, 49% yield) as a yellow solid.
  • Example 2 7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl- 3-(o-tolyl)-4H-quinolizin-4-one.
  • Example 3 8-(4-Ethyl-3-(hydroxymethyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1- isopropyl-3-(o-tolyl)-4H-quinolizin-4-one.
  • Example 4 3-(5-Chloro-3-methyl-1H-pyrazol-4-yl)-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1- methyl-1H-imidazol-4-yl)-1-isopropyl-4H-quinolizin-4-one.
  • CS 2 CO 3 168 mg, 514 ⁇ mol
  • dioxane/H 2 O v/v, 5/1, 4 mL
  • 5- chloro-3-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole Intermediate 5, 56 mg, 228 ⁇ mol
  • the yellow solid was purified by preparative reversed phase HPLC (Stationary phase: Boston Prime C18, 5 ⁇ m, 150 ⁇ 30 mm; Mobile phase: water (0.05% NH 3 H 2 O + 10 mM NH 4 HCO 3 ) (A) - MeCN (B), gradient elution: 27 - 57% B in A over 8 min, flow rate: 30 mL/min) to give the title compound (12.5 mg, 24% yield) as a yellow solid.
  • Example 5 3-(5-Chloro-3-methyl-1H-pyrazol-4-yl)-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1- methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one.
  • Example 6 7-Fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-3- (3-methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)-4H-quinolizin-4-one.
  • Example 7 7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl- 3-(3-methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)-4H-quinolizin-4-one.
  • Example 8 3-(2-Chloro-4-methylpyridin-3-yl)-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl- 1H-imidazol-4-yl)-1-isopropyl-4H-quinolizin-4-one.
  • the yellow solid was purified by preparative reversed phase HPLC (Stationary phase: Boston Prime C18, 5 ⁇ m, 150 ⁇ 30 mm; Mobile phase: water (0.05% NH 3 H 2 O + 10 mM NH 4 HCO 3 ) (A) - MeCN (B), gradient elution: 35 - 63% B in A over 8 min, flow rate: 30 mL/min) to give the title compound (14.1 mg, 26% yield) as a yellow solid.
  • Example 9 3-(2-Chloro-4-methylpyridin-3-yl)-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl- 1H-1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one.
  • Biological Data DHODH inhibitory activities of the compounds of Examples 1-9 were assessed using the following assays.
  • the half maximal inhibitory concentration values (IC 50 ) are summarized in Table 3.
  • the assay buffer contained 50 nM HEPES, pH 7.5, 150 mM NaCl, 0.5 mM EDTA, and 0.1% Triton X-100 in MilliQ water.
  • Substrate consisting of 20 mM DHO, 5mM CoQ 6 , and 1mM DCIP in assay buffer, initiates the reaction.
  • the assay is run in end-point mode by quenching the reaction with the potent DHODH inhibitor brequinar. Absorbance measurements were obtained using the BMG Phera Star plate-reading spectrophotomer.
  • Purified human DHODH was purchased from Proteros (cat. No. PR-0044). Chemicals were purchased from Sigma-Aldrich, Teknova, and Avanti Polar Lipids.
  • MOLM-13 Cellular Assay MOLM-13 cells (human acute myeloid leukemia cells) were obtained from DSMZ and were maintained in RPMI 1640 + Glutamax + 25mM HEPES (Invitrogen, catalog number 72400) supplemented with 10% heat inactivated fetal bovine serum (FBS; Invitrogen, catalog number 16140). The day prior to assay set-up, cells were pelleted, resuspended in fresh media, counted, and cells were plated at 0.4 x 10 6 cell/mL in a T150 flask.
  • FBS heat inactivated fetal bovine serum

Abstract

Disclosed are compounds, compositions and methods for treating diseases, disorders, or medical conditions that are affected by the modulation of DHODH. Such compounds are represented by Formula (I) as follows, wherein R1, R2, R3, R4, are defined herein.

Description

DIHYDROOROTATE DEHYDROGENASE INHIBITORS CROSS REFERENCE TO RELATED APPLICATIONS This application is entitled to priority pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No.63/085,317, filed on September 30, 2020, the disclosure of which is incorporated by reference herein in its entirety. FIELD OF THE INVENTION The present invention relates to novel compounds that are dihydroorotate dehydrogenase (DHODH) inhibitors. These compounds may be useful for the treatment of a disease, disorder, or medical condition where there is an advantage in inhibiting DHODH. The invention also relates to pharmaceutical compositions comprising one or more of such compounds, to processes to prepare such compounds and compositions, and to the use of such compounds or pharmaceutical compositions for the method of treatment of cancer, and autoimmune and inflammatory diseases, syndromes, and disorders. BACKGROUND OF THE INVENTION Acute myelogenous leukemia (AML) is a clonal disease of the blood and bone marrow resulting from mutations that occur in normal hematopoietic stem cells. AML is a heterogenous disease in that it presents with a range of cytogenetic, morphological and immunophenotypic features, and is characterized by an accumulation of clonal, abnormal myeloid progenitor cells, known as myeloblasts. These cells demonstrate disruption of normal myeloid differentiation and excessive proliferation, resulting in the decreased formation of hematopoietic cells. Disease remission can be achieved with standard induction chemotherapy, but refractory and relapsed disease remains a challenge due to persistence of leukemic stem cells. Therefore, AML represents an unmet medical need with >20,000 new cases per year in the US with 5-year overall survival below 30% (Stein ET et al., Health Qual Life Outcomes 16: 193, 2018). Differentiation therapy is considered an attractive approach to AML treatment based on the knowledge that differentiation and loss of stem cell self-renewal are coupled in normal cells. Treatment of acute promyelocytic leukemia, which represents 10-15% of all AML, with all-trans retinoic acid is the paradigm for differentiation therapy. Retinoic acid targets the promyelocytic leukemia protein (PML)-retinoic acid receptor-α (RAR-α) fusion protein encoded by a t(15,17) chromosomal translocation. Targeting PML-RAR specifically lifts the transcriptionally mediated differentiation block induced by the fusion protein and early clinical trials with single agent ATRA demonstrated complete hematologic remission in all treated patients (McCulloch D et al. Onco Targets Ther 2017; 10: 1585–1601; Nowak D et al. Blood 113: 3655, 2009). Although differentiation therapy is successful, it is only applicable to a small population of AML patients. Research efforts have aimed at identifying additional differentiation inducing agents, but with limited success. Recently dihydroorotate dehydrogenase (DHODH) emerged as a potentially more broadly applicable differentiation target in a phenotypic screen aimed at identifying small molecules that overcome blockade of the maturation of primary murine bone marrow cells expressing the homeobox protein HoxA9. This protein is a key transcription factor involved in balancing stem cell maintenance/differentiation and is normally expressed in hematopoietic progenitor cells and downregulated upon induction of differentiation and has been found to be widely overexpressed in AML (Sykes et al., Cell 167: 171, 2016). DHODH is a flavin mononucleotide (FMN) flavoprotein located in the inner mitochondrial membrane that catalyzes the oxidation of dihydroorotate to orotate, the fourth step in the de novo pyrimidine biosynthesis pathway. Inhibition of DHODH leads to decreased pyrimidine synthesis important precursors for nucleotide synthesis, but also glycoprotein and phospholipid biosynthesis (Reis RAG et al., Archives Biochem Biophysics 632: 175, 2017; Vyas VK et al., Mini Rev Med Chem 11: 1039, 2011). DHODH is a validated target for the treatment of autoimmune diseases with the FDA approved small molecule DHODH inhibitors leflunomide and teriflunomide for rheumatoid arthritis and multiple sclerosis, respectively (Lolli ML et al., Recent patents on Anti-Cancer Drug Discovery 13: 86, 2018). Since the first observation by Sykes et al. demonstrating that DHODH inhibition drives AML differentiation in vitro, as evidenced by upregulation of the differentiation markers CD11b and CD14, and results in dose dependent anti-leukemic effects, decreased leukemic stem cells and prolonged survival in vivo, additional evidence emerged demonstrating that small molecule DHODH inhibitors mediate antiproliferative activity against AML cells with concomitant cell cycle arrest, upregulation of CD11b and CD14, and induction of apoptosis (Wu D et al.. Haematologica 103: 1472, 2018; Sainas S et al., J Med Chem 61: 6034, 2018; Cao L et al., Mol Cancer Ther, October 23rd Epub ahead of print). Moreover, preclinical solid tumor in vitro and in vivo models demonstrated effectiveness of DHODH inhibition and DHODH was identified as a synthetic lethality in PTEN and KRAS mutant solid tumors (Pharmacology and Therapeutics, Epub October 19th, 2018; Mathur D et al., Cancer Discovery 7: 1, 2017; Cell Chemical Biology 25: 1, 2018). Thus, there remains a need for DHODH inhibitors that provide a therapeutic benefit to patients suffering from cancer and/or inflammatory and immunological diseases. SUMMARY OF THE INVENTION Embodiments of the present invention relate to compounds, pharmaceutical compositions containing them, methods of making and purifying them, methods of using them as inhibitors of DHODH enzymatic activity and methods for using them in the treatment of a subject suffering from or diagnosed with a disease, disorder, or medical condition such as autoimmune or inflammatory disorders, or diseases such as cancer. Embodiments of this invention include compounds of Formula (I), wherein R1 is C1-6alkyl or C1-6haloalkyl;
Figure imgf000004_0001
Figure imgf000004_0002
Rb is C1-6alkyl substituted with one OH member; R3 is H or halo; R4 is selected from the group consisting of:
Figure imgf000004_0003
Figure imgf000005_0001
wherein Re is selected from the group consisting of: H; halo; C1-6alkyl; C1-6alkyl substituted with one member selected from the group consisting of: OH, OCH3, and OCF3; C1-6haloalkyl; C1-6haloalkyl substituted with one member selected from the group consisting of: OH, and OCH3; and OC1-6alkyl; Rf is selected from the group consisting of: H; halo; C1-6alkyl; C1-6alkyl substituted with one member selected from the group consisting of: OH, OCH3, and OCF3; C1-6haloalkyl; C1-6haloalkyl substituted with one member selected from the group consisting of: OH, and OCH3; and OC1-6alkyl; and Rg is H or C1-6alkyl; or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer thereof. The present invention further provides methods for treating or ameliorating a disease, syndrome, condition, or disorder in a subject, including a mammal and/or human in which the disease, syndrome, condition, or disorder is affected by the inhibition of DHODH enzymatic activity, including but not limited to, cancer and/or inflammatory or immunological diseases, using a compound of Formula (I) or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer thereof. Additional embodiments, features, and advantages of the invention will be apparent from the following detailed description and through practice of the invention. DETAILED DESCRIPTION OF THE INVENTION Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in art. As used in the specification and the appended claims, unless specified to the contrary, the following terms have the meaning indicated in order to facilitate the understanding of the present invention. The singular forms "a'', "an" and "the" encompass plural references unless the context clearly indicates otherwise. With reference to substituents, the term “independently” refers to the situation where when more than one substituent is possible, the substituents may be the same or different from each other. The term “substituted” means that the specified group or moiety bears one or more substituents. The term "unsubstituted" means that the specified group bears no substituents. The term “optionally substituted” means that the specified group is unsubstituted or substituted by one or more substituents. Where the term “substituted” is used to describe a structural system, the substitution is meant to occur at any valency-allowed position on the system. Unless qualified specifically in particular instances of use, the term “alkyl” refers to a straight- or branched-chain alkyl group having from 1 to 8 carbon atoms in the chain. Examples of alkyl groups include methyl (Me), ethyl (Et), n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl (tBu), pentyl, isopentyl, tert-pentyl, hexyl, isohexyl, and groups that in light of the ordinary skill in the art and the teachings provided herein would be considered equivalent to any one of the foregoing examples. “C1-6alkyl” refers to straight- or branched-chain alkyl group having from 1 to 6 carbon atoms in the chain. “C1-4alkyl” refers to straight- or branched-chain alkyl group having from 1 to 4 carbon atoms in the chain. The term “cycloalkyl” refers to a saturated or partially saturated, monocyclic, fused polycyclic, or spiro polycyclic carbocycle having from 3 to 12 ring atoms per carbocycle. “C3- 6cycloalkyl” refers to a carbocycle having from 3 to 6 ring atoms per carbocycle. Illustrative examples of cycloalkyl groups include the following entities, in the form of properly bonded moieties:
Figure imgf000006_0001
The term “halogen” or “halo” represents chlorine, fluorine, bromine, or iodine. The term “haloalkyl” refers to a straight- or branched-chain alkyl group having from 1 to 6 carbon atoms in the chain optionally substituting hydrogens with halogens. The term “ C1-6 haloalkyl” as used here refers to a straight- or branched-chain alkyl group having from 1 to 6 carbon atoms in the chain, optionally substituting hydrogens with halogens. The term “C1-4 haloalkyl” as used here refers to a straight- or branched-chain alkyl group having from 1 to 4 carbon atoms in the chain, optionally substituting hydrogens with halogens. Examples of “haloalkyl” groups include trifluoromethyl (CF3), difluoromethyl (CF2H), monofluoromethyl (CH2F), pentafluoroethyl (CF2CF3), tetrafluoroethyl (CHFCF3), monofluoroethyl (CH2CH2F), trifluoroethyl (CH2CF3), tetrafluorotrifluoromethylethyl (CF(CF3)2), and groups that in light of the ordinary skill in the art and the teachings provided herein would be considered equivalent to any one of the foregoing examples. The term “aryl” refers to a monocyclic, aromatic carbocycle (ring structure having ring atoms that are all carbon) having 6 atoms per ring. (Carbon atoms in the aryl groups are sp2 hybridized.) The term “phenyl” represents the following moiety:
Figure imgf000007_0001
The term “heteroaryl” refers to a monocyclic or fused bicyclic heterocycle (ring structure having ring atoms selected from carbon atoms and up to four heteroatoms selected from nitrogen, oxygen, and sulfur) having from 3 to 9 ring atoms per heterocycle. Illustrative examples of heteroaryl groups include the following entities, in the form of properly bonded moieties:
Figure imgf000007_0002
Those skilled in the art will recognize that the species of cycloalkyl, heteroaryl and aryl groups listed or illustrated above are not exhaustive, and that additional species within the scope of these defined terms may also be selected. The term “variable point of attachment” means that a group is allowed to be attached at more than one alternative position in a structure. The attachment will always replace a hydrogen atom on one of the ring atoms. In other words, all permutations of bonding are represented by the single diagram, as shown in the illustrations below.
Figure imgf000007_0003
Those skilled in the art will recognize that that if more than one such substituent is present for a given ring, the bonding of each substituent is independent of all of the others. The groups listed or illustrated above are not exhaustive. As used herein, the term "or" means "and/or" unless stated otherwise. As used herein, the terms "including", "containing" and “comprising” are used in their open, non-limiting sense. As used herein, the term "composition" is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts. As used herein, the term “treat”, “treating”, or “treatment” of any disease, condition, syndrome or disorder refers, in one embodiment, to ameliorating the disease, condition, syndrome or disorder (i.e. slowing or arresting or reducing the development of the disease or at least one of the clinical symptoms thereof). In another embodiment, “treat”, “treating”, or “treatment” refers to alleviating or ameliorating at least one physiological or biochemical parameter associated with or causative of the disease, condition, syndrome or disorder, including those which may not be discernible by the patient. In a further embodiment, “treat”, “treating”, or “treatment” refers to modulating the disease, condition, syndrome or disorder either physically (e.g. stabilization of a discernible symptom), physiologically, (e.g. stabilization of a physical parameter), or both. In yet another embodiment, “treat”, “treating”, or “treatment” refers to preventing or delaying the onset or development or progression of the disease, condition, syndrome or disorder. The terms “subject” and “patient” are used interchangeably herein and may refer to an animal, preferably a mammal, most preferably a human. As used herein, the terms active compound, pharmaceutical agent and active ingredient are used interchangeably to refer to a pharmaceutically active compound. Other ingredients in a drug composition, such as carriers, diluents or excipients, may be substantially or completely pharmaceutically inert. A pharmaceutical composition (also referred to herein as a composition or formulation) may comprise the active ingredient in combination with one or more carriers and/or one or more excipients and/or one or more diluents. The term “therapeutically effective amount” (used interchangeably herein with “effective amount”) refers to an amount (e.g., of an active compound or pharmaceutical agent, such as a compound of the present invention), which elicits the biological or medicinal response in a tissue system, animal or human that is being sought by a researcher, veterinarian, medical doctor or other clinician, including reduction or inhibition of an enzyme or a protein activity, or ameliorating symptoms, alleviating conditions, slowing or delaying disease progression, or preventing a disease. Stated another way, the term therapeutically effective amount may refer to an amount that, when administered to a particular subject, achieves a therapeutic effect by inhibiting, alleviating or curing a disease, condition, syndrome or disorder in the subject or by prophylactically inhibiting, preventing or delaying the onset of a disease, condition, syndrome or disorder, or symptom(s) thereof. A therapeutically effective amount may be an amount which relieves to some extent one or more symptoms of a disease, condition, syndrome or disorder in a subject; and/or returns to normal either partially or completely one or more physiological or biochemical parameters associated with or causative of the disease, condition, syndrome or disorder; and/or reduces the likelihood of the onset of the disease, condition, syndrome or disorder, or symptom(s) thereof. "Pharmaceutically acceptable" means that, which is useful in preparing a pharmaceutical composition that is generally safe, non-toxic and neither biologically nor otherwise undesirable and includes that which is acceptable for veterinary as well as human pharmaceutical use. A "pharmaceutically acceptable salt” is intended to mean a salt of an acid or base of a compound represented by Formula (I) (as well as compounds of Formula (IA), (IB), and (IC)) that is non-toxic, biologically tolerable, or otherwise biologically suitable for administration to the subject. See, generally, S.M. Berge, et al., “Pharmaceutical Salts”, J. Pharm. Sci., 1977, 66:1-19, and Handbook of Pharmaceutical Salts, Properties, Selection, and Use, Stahl and Wermuth, Eds., Wiley-VCH and VHCA, Zurich, 2002. Preferred pharmaceutically acceptable salts are those that are pharmacologically effective and suitable for contact with the tissues of patients without undue toxicity, irritation, or allergic response. Non-limiting examples of pharmaceutically acceptable salts include sulfates, pyrosulfates, bisulfates, sulfites, bisulfites, phosphates, monohydrogen-phosphates, dihydrogenphosphates, metaphosphates, pyrophosphates, chlorides, bromides, iodides, acetates, propionates, decanoates, caprylates, acrylates, formates, isobutyrates, caproates, heptanoates, propiolates, oxalates, malonates, succinates, suberates, sebacates, fumarates, maleates, butyne- 1,4-dioates, hexyne-1,6-dioates, benzoates, chlorobenzoates, methylbenzoates, dinitrobenzoates, hydroxybenzoates, methoxybenzoates, phthalates, sulfonates, xylenesulfonates, phenylacetates, phenylpropionates, phenylbutyrates, citrates, lactates, γ-hydroxybutyrates, glycolates, tartrates, methane-sulfonates, propanesulfonates, naphthalene-1-sulfonates, naphthalene-2-sulfonates, and mandelates. A compound of Formula (I) may possess a sufficiently acidic group, a sufficiently basic group, or both types of functional groups, and accordingly react with a number of inorganic or organic bases, and inorganic and organic acids, to form a pharmaceutically acceptable salt. Compounds of Formula (I) may contain at least one nitrogen of basic character, so desired pharmaceutically acceptable salts may be prepared by any suitable method available in the art, for example, treatment of the free base with an inorganic acid, such as hydrochloric acid, hydrobromic acid, sulfuric acid, sulfamic acid, nitric acid, boric acid, phosphoric acid, and the like, or with an organic acid, such as acetic acid, phenylacetic acid, propionic acid, stearic acid, lactic acid, ascorbic acid, maleic acid, hydroxymaleic acid, isethionic acid, succinic acid, valeric acid, fumaric acid, malonic acid, pyruvic acid, oxalic acid, glycolic acid, salicylic acid, oleic acid, palmitic acid, lauric acid, a pyranosidyl acid, such as glucuronic acid or galacturonic acid, an alpha-hydroxy acid, such as mandelic acid, citric acid, or tartaric acid, an amino acid, such as aspartic acid or glutamic acid, an aromatic acid, such as benzoic acid, 2-acetoxybenzoic acid, naphthoic acid, or cinnamic acid, a sulfonic acid, such as laurylsulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, any compatible mixture of acids such as those given as examples herein, and any other acid and mixture thereof that are regarded as equivalents. Compounds of Formula (I) may contain a carboxylic acid moiety, a desired pharmaceutically acceptable salt may be prepared by any suitable method, for example, treatment of the free acid with an inorganic or organic base, such as an amine (primary, secondary or tertiary), an alkali metal hydroxide, alkaline earth metal hydroxide, any compatible mixture of bases such as those given as examples herein, and any other base and mixture thereof that are regarded as equivalents or acceptable substitutes in light of the ordinary level of skill in this technology. Illustrative examples of suitable salts include organic salts derived from amino acids, such as glycine and arginine, ammonia, carbonates, bicarbonates, primary, secondary, and tertiary amines, and cyclic amines, such as benzylamines, pyrrolidines, piperidine, morpholine, piperazine, N-methyl-glucamine and tromethamine and inorganic salts derived from sodium, calcium, potassium, magnesium, manganese, iron, copper, zinc, aluminum, and lithium. Each compound used herein may be discussed interchangeably with respect to its chemical formula, chemical name, abbreviation, etc. Any formula given herein is intended to represent compounds having structures depicted by the structural formula as well as certain variations or forms. In particular, compounds of any formula given herein may have asymmetric centers and therefore exist in different enantiomeric forms. All optical isomers and stereoisomers of the compounds of the general formula, and mixtures thereof, are considered within the scope of such formula. The compounds of this invention may possess one or more asymmetric centers; such compounds can therefore be produced as individual (R)- or (S)-stereoisomers or as mixtures thereof. Thus, any formula given herein is intended to represent a racemate, one or more of its enantiomeric forms, one or more of its diastereomeric forms, and mixtures thereof. Additionally, any formula given herein is intended to refer also to any one of: hydrates, solvates, polymorphs and of such compounds, and mixtures thereof, even if such forms are not listed explicitly. The term “R” at a stereocenter designates that the stereocenter is purely of the R- configuration as defined in the art; likewise, the term “S” means that the stereocenter is purely of the S-configuration. As used herein, the term “RS” refers to a stereocenter that exists as a mixture of the R- and S-configurations. Compounds containing one stereocenter drawn without a stereo bond designation are a mixture of 2 enantiomers. Compounds containing 2 stereocenters both drawn without stereo bond designations are a mixture of 4 diastereomers. Compounds with 2 stereocenters both labeled “RS” and drawn with stereo bond designations are a 2-component mixture with relative stereochemistry as drawn. Unlabeled stereocenters drawn without stereo bond designations are a mixture of the R- and S-configurations. For unlabeled stereocenters drawn with stereo bond designations, the absolute stereochemistry is as depicted. Unless indicated otherwise, the description or naming of a particular compound in the specification and claims is intended to include both individual enantiomers and mixtures, racemic or otherwise, thereof. The methods for the determination of stereochemistry and the separation of stereoisomers are well-known in the art. Reference to a compound herein stands for a reference to any one of: (a) the recited form of such compound, and (b) any of the forms of such compound in the medium in which the compound is being considered when named. For example, reference herein to a compound such as R-COOH, encompasses reference to any one of: for example, R-COOH(s), R-COOH(sol), and R-COO-(sol). In this example, R-COOH(s) refers to the solid compound, as it could be for example in a tablet or some other solid pharmaceutical composition or preparation; R- COOH(sol) refers to the undissociated form of the compound in a solvent; and R-COO-(sol) refers to the dissociated form of the compound in a solvent, such as the dissociated form of the compound in an aqueous environment, whether such dissociated form derives from R-COOH, from a salt thereof, or from any other entity that yields R-COO- upon dissociation in the medium being considered. In another example, an expression such as “exposing an entity to compound of formula R-COOH” refers to the exposure of such entity to the form, or forms, of the compound R-COOH that exists, or exist, in the medium in which such exposure takes place. In still another example, an expression such as “reacting an entity with a compound of formula R-COOH” refers to the reacting of (a) such entity in the chemically relevant form, or forms, of such entity that exists, or exist, in the medium in which such reacting takes place, with (b) the chemically relevant form, or forms, of the compound R-COOH that exists, or exist, in the medium in which such reacting takes place. In this regard, if such entity is for example in an aqueous environment, it is understood that the compound R-COOH is in such same medium, and therefore the entity is being exposed to species such as R-COOH(aq) and/or R-COO-(aq), where the subscript “(aq)” stands for “aqueous” according to its conventional meaning in chemistry and biochemistry. A carboxylic acid functional group has been chosen in these nomenclature examples; this choice is not intended, however, as a limitation but it is merely an illustration. It is understood that analogous examples can be provided in terms of other functional groups, including but not limited to hydroxyl, basic nitrogen members, such as those in amines, and any other group that interacts or transforms according to known manners in the medium that contains the compound. Such interactions and transformations include, but are not limited to, dissociation, association, tautomerism, solvolysis, including hydrolysis, solvation, including hydration, protonation, and deprotonation. No further examples in this regard are provided herein because these interactions and transformations in a given medium are known by any one of ordinary skill in the art. Any formula given herein is also intended to represent unlabeled forms as well as isotopically labeled forms of the compounds. Isotopically labeled compounds have structures depicted by the formulas given herein except that one or more atoms are replaced by an atom having a selected atomic mass or mass number in an enriched form. Examples of isotopes that can be incorporated into compounds of the invention in a form that exceeds natural abundances include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, fluorine, chlorine, and iodine, such as 2H (or chemical symbol D), 3H (or chemical symbol T), 11C, 13C, 14C, 15N, 18O, 17O, 31P, 32P, 35S, 18F, 36Cl, and 125I, respectively. Such isotopically labelled compounds are useful in metabolic studies (preferably with 14C), reaction kinetic studies (with, for example 2H or 3H), detection or imaging techniques [such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT)] including drug or substrate tissue distribution assays, or in radioactive treatment of patients. In particular, an 18F or 11C labeled compound may be particularly preferred for PET or SPECT studies. Further, substitution with heavier isotopes such as deuterium (i.e., 2H, or D) may afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements. Isotopically labeled compounds of this invention can generally be prepared by carrying out the procedures disclosed in the schemes or in the examples and preparations described below by substituting a readily available isotopically labeled reagent for a non-isotopically labeled reagent. The term Cn-m alkyl refers to an aliphatic chain, whether straight or branched, with a total number N of carbon members in the chain that satisfies n ≤ N ≤ m, with m > n. When the same plurality of substituents is assigned to various groups, the specific individual substituent assignment to each of such groups is meant to be independently made with respect to the specific individual substituent assignments to the remaining groups. By way of illustration, but not as a limitation, if each of groups Q and R can be H or F, the choice of H or F for Q is made independently of the choice of H or F for R, so the choice of assignment for Q does not determine or condition the choice of assignment for R, or vice-versa, unless it is expressly indicated otherwise. Illustrative claim recitation in this regard would read as “each of Q and R is independently H or F”, or “each of Q and R is independently selected from the group consisting of H and F”. In another example, a zwitterionic compound would be encompassed herein by referring to a compound that is known to form a zwitterion, even if it is not explicitly named in its zwitterionic form. Terms such as zwitterion, zwitterions, and their synonyms zwitterionic compound(s) are standard IUPAC-endorsed names that are well known and part of standard sets of defined scientific names. In this regard, the name zwitterion is assigned the name identification CHEBI:27369 by the Chemical Entities of Biological Interest (ChEBI) dictionary of molecular entities. As generally well known, a zwitterion or zwitterionic compound is a neutral compound that has formal unit charges of opposite sign. Sometimes these compounds are referred to by the term “inner salts”. Other sources refer to these compounds as “dipolar ions”, although the latter term is regarded by still other sources as a misnomer. As a specific example, aminoethanoic acid (the amino acid glycine) has the formula H2NCH2COOH, and it exists in some media (in this case in neutral media) in the form of the zwitterion +H3NCH2COO-. Zwitterions, zwitterionic compounds, inner salts and dipolar ions in the known and well- established meanings of these terms are within the scope of this invention, as would in any case be so appreciated by those of ordinary skill in the art. Because there is no need to name each and every embodiment that would be recognized by those of ordinary skill in the art, no structures of the zwitterionic compounds that are associated with the compounds of this invention are given explicitly herein. They are, however, part of the embodiments of this invention. No further examples in this regard are provided herein because the interactions and transformations in a given medium that lead to the various forms of a given compound are known by any one of ordinary skill in the art. When referring to any formula given herein, the selection of a particular moiety from a list of possible species for a specified variable is not intended to define the same choice of the species for the variable appearing elsewhere. In other words, where a variable appears more than once, the choice of the species from a specified list is independent of the choice of the species for the same variable elsewhere in the formula, unless stated otherwise. By way of a first example on substituent terminology, if substituent S1 example is one of S1 and S2, and substituent S2 example is one of S3 and S4, then these assignments refer to embodiments of this invention given according to the choices S1 example is S1 and S2 example is S3; S1 example is S1 and S2 example is S4; S1 example is S2 and S2 example is S3; S1 example is S2 and S2 example is S4; and equivalents of each one of such choices. The shorter terminology “S1 example is one of S1 and S2, and S2 example is one of S3 and S4” is accordingly used herein for the sake of brevity, but not by way of limitation. The foregoing first example on substituent terminology, which is stated in generic terms, is meant to illustrate the various substituent assignments described herein. Furthermore, when more than one assignment is given for any member or substituent, embodiments of this invention comprise the various groupings that can be made from the listed assignments, taken independently, and equivalents thereof. By way of a second example on substituent terminology, if it is herein described that substituent Sexample is one of S1, S2, and S3, this listing refers to embodiments of this invention for which Sexample is S1; Sexample is S2; Sexample is S3; Sexample is one of S1 and S2; Sexample is one of S1 and S3; Sexample is one of S2 and S3; Sexample is one of S1, S2 and S3; and Sexample is any equivalent of each one of these choices. The shorter terminology “Sexample is one of S1, S2, and S3” is accordingly used herein for the sake of brevity, but not by way of limitation. The foregoing second example on substituent terminology, which is stated in generic terms, is meant to illustrate the various substituent assignments described herein. The nomenclature “Ci-Cj” with j > i, when applied herein to a class of substituents, is meant to refer to embodiments of this invention for which each and every one of the number of carbon members, from i to j including i and j, is independently realized. By way of example, the term C1-C3 refers independently to embodiments that have one carbon member ( C1), embodiments that have two carbon members (C2), and embodiments that have three carbon members (C3). Embodiments of this invention include compounds of Formula (I),
Figure imgf000015_0001
wherein R1 is C1-6alkyl or C1-6haloalkyl;
Figure imgf000015_0002
Ra is C1-6alkyl; Rb is C1-6alkyl substituted with one OH member; R3 is H or halo;
Figure imgf000015_0003
Figure imgf000016_0001
wherein Re is selected from the group consisting of: H; halo; C1-6alkyl; C1-6alkyl substituted with one member selected from the group consisting of: OH, OCH3, and OCF3; C1-6haloalkyl; C1-6haloalkyl substituted with one member selected from the group consisting of: OH, and OCH3; and OC1-6alkyl; Rf is selected from the group consisting of: H; halo; C1-6alkyl; C1-6alkyl substituted with one member selected from the group consisting of: OH, OCH3, and OCF3; C1-6haloalkyl; C1-6haloalkyl substituted with one member selected from the group consisting of: OH, and OCH3; and OC1-6alkyl; and Rg is H or C1-6alkyl; or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer thereof. An additional embodiment of the invention is a compound of Formula (I) wherein R1 is C1-4alkyl. An additional embodiment of the invention is a compound of Formula (I) wherein R1 is CH(CH3)2. An additional embodiment of the invention is a compound of Formula (I) wherein R2 is
Figure imgf000016_0002
An additional embodiment of the invention is a compound of Formula (I) wherein R2 is
Figure imgf000016_0003
An additional embodiment of the invention is a compound of Formula (I) wherein R2 is
Figure imgf000016_0004
An additional embodiment of the invention is a compound of Formula (I) wherein R3 is F. An additional embodiment of the invention is a compound of Formula (I) wherein R4 is
Figure imgf000017_0001
An additional embodiment of the invention is a compound of Formula (I) wherein R4 is
Figure imgf000017_0002
An additional embodiment of the invention is a compound of Formula (I) wherein R4 is
Figure imgf000017_0003
An additional embodiment of the current invention is a compound selected from the compounds shown below in Table 1, and pharmaceutically acceptable salts, isotopes, N-oxides, solvates, and stereoisomers thereof: Table 1 Example # Compound Name
Figure imgf000017_0004
Figure imgf000018_0001
Also within the scope of the invention are enantiomers and diastereomers of the compounds of Formula (I). Also within the scope of the invention are the pharmaceutically acceptable salts, N-oxides or solvates of the compounds of Formula (I). Also within the scope of the invention are the pharmaceutically acceptable prodrugs of compounds of Formula (I), and pharmaceutically active metabolites of the compounds of Formula (I). Also within the scope of the invention are isotopic variations of compounds of Formula (I), such as, e.g., deuterated compounds of Formula (I). Also within the scope of the invention are the pharmaceutically acceptable salts, N-oxides or solvates of the isotopic variations of the compounds of Formula (I). Also within the scope of the invention are the pharmaceutically acceptable prodrugs of the isotopic variations of the compounds of Formula (I), and pharmaceutically active metabolites of the isotopic variations of the compounds of Formula (I). Even though the compounds of embodiments of the present invention (including their pharmaceutically acceptable salts and pharmaceutically acceptable solvates) can be administered alone, they will generally be administered in admixture with a pharmaceutically acceptable carrier, a pharmaceutically acceptable excipient and/or a pharmaceutically acceptable diluent selected with regard to the intended route of administration and standard pharmaceutical or veterinary practice. Thus, particular embodiments of the present invention are directed to pharmaceutical and veterinary compositions comprising compounds of Formula (I) and at least one pharmaceutically acceptable carrier, pharmaceutically acceptable excipient, and/or pharmaceutically acceptable diluent. By way of example, in the pharmaceutical compositions of embodiments of the present invention, the compounds of Formula (I) may be admixed with any suitable binder(s), lubricant(s), suspending agent(s), coating agent(s), solubilizing agent(s), and combinations thereof. An embodiment of the invention relates to a pharmaceutical composition comprising an effective amount of at least one compound selected from compounds of Formula (I), and pharmaceutically acceptable salts, isotopes, N-oxides, solvates, and stereoisomers thereof, in accordance with any embodiment described herein; and at least one pharmaceutically acceptable excipient. An additional embodiment of the invention is a pharmaceutical composition comprising: (A) an effective amount of at least one compound selected from compounds of Formula (I) R1 R2 wherein R1 is C1-6alkyl or C1-6haloalkyl;
Figure imgf000019_0001
R2 i
Figure imgf000019_0002
R3 is H or halo; R4 is selected from the group consisting of:
Figure imgf000019_0003
wherein Re is selected from the group consisting of: H; halo; C1-6alkyl; C1-6alkyl substituted with one member selected from the group consisting of: OH, OCH3, and OCF3; C1-6haloalkyl; C1-6haloalkyl substituted with one member selected from the group consisting of: OH, and OCH3; and OC1-6alkyl; Rf is selected from the group consisting of: H; halo; C1-6alkyl; C1-6alkyl substituted with one member selected from the group consisting of: OH, OCH3, and OCF3; C1-6haloalkyl; C1-6haloalkyl substituted with one member selected from the group consisting of: OH, and OCH3; and OC1-6alkyl; and Rg is H or C1-6alkyl; or pharmaceutically acceptable salts, isotopes, N-oxides, solvates, or stereoisomers thereof; and (B) at least one pharmaceutically acceptable excipient. An additional embodiment of the invention is a pharmaceutical composition comprising an effective amount of a compound shown in Table 1 (e.g., a compound selected from Examples 1-9), or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer of the compound of Table 1, a pharmaceutically acceptable prodrug of the compound of Table 1, or a pharmaceutically active metabolite of the compound of Table 1; and at least one pharmaceutically acceptable excipient. Solid oral dosage forms such as, tablets or capsules, containing one or more compounds of the present invention may be administered in at least one dosage form at a time, as appropriate. It is also possible to administer the compounds in sustained release formulations. Additional oral forms in which the present inventive compounds may be administered include elixirs, solutions, syrups, and suspensions; each optionally containing flavoring agents and coloring agents. Alternatively, one or more compounds of Formula (I) can be administered by inhalation (intratracheal or intranasal) or in the form of a suppository or pessary, or they may be applied topically in the form of a lotion, solution, cream, ointment or dusting powder. For example, they can be incorporated into a cream comprising, consisting of, and/or consisting essentially of an aqueous emulsion of polyethylene glycols or liquid paraffin. They can also be incorporated, at a concentration of between about 1 % and about 10 % by weight of the cream, into an ointment comprising, consisting of, and/or consisting essentially of a wax or soft paraffin base together with any stabilizers and preservatives as may be required. An alternative means of administration includes transdermal administration by using a skin or transdermal patch. The pharmaceutical compositions of the present invention (as well as the compounds of the present invention alone) can also be injected parenterally, for example, intracavernosally, intravenously, intramuscularly, subcutaneously, intradermally, or intrathecally. In this case, the compositions will also include at least one of a suitable carrier, a suitable excipient, and a suitable diluent. For parenteral administration, the pharmaceutical compositions of the present invention are best used in the form of a sterile aqueous solution that may contain other substances, for example, enough salts and monosaccharides to make the solution isotonic with blood. For buccal or sublingual administration, the pharmaceutical compositions of the present invention may be administered in the form of tablets or lozenges, which can be formulated in a conventional manner. By way of further example, pharmaceutical compositions containing at least one of the compounds of Formula (I) as the active ingredient can be prepared by mixing the compound(s) with a pharmaceutically acceptable carrier, a pharmaceutically acceptable diluent, and/or a pharmaceutically acceptable excipient according to conventional pharmaceutical compounding techniques. The carrier, excipient, and diluent may take a wide variety of forms depending upon the desired route of administration (e.g., oral, parenteral, etc.). Thus, for liquid oral preparations such as, suspensions, syrups, elixirs and solutions, suitable carriers, excipients and diluents include water, glycols, oils, alcohols, flavoring agents, preservatives, stabilizers, coloring agents and the like; for solid oral preparations such as, powders, capsules, and tablets, suitable carriers, excipients and diluents include starches, sugars, diluents, granulating agents, lubricants, binders, disintegrating agents and the like. Solid oral preparations also may be optionally coated with substances such as, sugars, or be enterically coated so as to modulate the major site of absorption and disintegration. For parenteral administration, the carrier, excipient and diluent will usually include sterile water, and other ingredients may be added to increase solubility and preservation of the composition. Injectable suspensions or solutions may also be prepared utilizing aqueous carriers along with appropriate additives such as, solubilizers and preservatives. According to particular embodiments, a therapeutically effective amount of a compound of Formula (I) or a pharmaceutical composition thereof may comprise a dose range from about 0.1 mg to about 3000 mg, or any particular amount or range therein, in particular from about 1 mg to about 1000 mg, or any particular amount or range therein, of active ingredient in a regimen of about 1 to about (4x) per day for an average (70 kg) human; although, it is apparent to one skilled in the art that the therapeutically effective amount for a compound of Formula (I) will vary as will the diseases, syndromes, conditions, and disorders being treated. An embodiment of the present invention is directed to a pharmaceutical composition for oral administration, comprising a compound of Formula (I) in an amount of from about 1 mg to about 500 mg. Advantageously, a compound of Formula (I) may be administered in a single daily dose, or the total daily dosage may be administered in divided doses of two, three and (4x) daily. Optimal dosages of a compound of Formula (I) to be administered may be readily determined and will vary with the particular compound used, the mode of administration, the strength of the preparation, and the advancement of the disease, syndrome, condition or disorder. In addition, factors associated with the particular subject being treated, including subject gender, age, weight, diet and time of administration, will result in the need to adjust the dose to achieve an appropriate therapeutic level and desired therapeutic effect. The above dosages are thus exemplary of the average case. There can be, of course, individual instances wherein higher or lower dosage ranges are merited, and such are within the scope of this invention. Compounds of Formula (I) may be administered in any of the foregoing compositions and dosage regimens or by means of those compositions and dosage regimens established in the art whenever use of a compound of Formula (I) is administered to a subject in need thereof. According to particular embodiments, one or more compounds of Formula (I) are useful in methods for treating, ameliorating and / or preventing a disease, a syndrome, a condition or a disorder that is affected by the inhibition of DHODH enzymatic activity. An additional embodiment of the invention relates to the use of compounds of Formula (I), e.g., by inhibiting dihydroorotate oxygenase enzyme activity, in treating disorders like inflammatory disorders, autoimmune disorders, or cancer; or pharmaceutically acceptable salts, isotopes, N-oxides, solvates, or stereoisomers thereof. In a further aspect the present invention provides a method for inhibiting or altering Dihydroorotate Dehydrogenase (DHODH) enzymatic activity, the method comprising contacting DHODH with any compound of Formula (I), aspect or embodiment disclosed herein, thereby inhibiting or otherwise altering DHODH enzymatic activity. An additional embodiment of the present invention provides methods for treating diseases, disorders, or medical conditions mediated or otherwise affected by dihydroorotate dehydrogenase (DHODH) enzyme activity comprising administering a compound of Formula (I) to a subject in need thereof. As used herein, the term "DHODH inhibitor" may refer to an agent that inhibits or reduces DHODH activity. In one embodiment, the term “therapeutically effective amount” (or “effective amount”) refers to the amount of a compound of the present invention that, when administered to a subject, is effective to (1) at least partially alleviate, inhibit, prevent, and/ or ameliorate a condition, or a disorder or a disease (i) mediated by DHODH enzymatic activity; or (ii) associated with DHODH enzymatic activity; or (iii) characterized by activity (normal or abnormal) of DHODH enzyme; or (2) reduce or inhibit the activity of DHODH enzyme; or (3) reduce or inhibit the expression of DHODH; or (4) modify the protein levels of DHODH. Without being bound by a particular theory, DHODH inhibitors are believed to act by inhibiting nucleic acid synthesis, cell cycle arrest or altering post-translational glycosylation of proteins involved in regulating myeloid differentiation within progenitor tumor cells. An additional embodiment of the invention is a method of treating a subject suffering from or diagnosed with a disease, disorder, or medical condition mediated or otherwise affected by DHODH enzymatic activity, comprising administering to a subject in need of such treatment an effective amount of at least one compound selected from: compounds of Formula (I), (such as a compound of Table 1), enantiomers and diastereomers of the compounds of Formula (I) (such as a compound of Table 1), isotopic variations of the compounds of Formula (I) (such as a compound of Table 1), and pharmaceutically acceptable salts of all of the foregoing. Stated another way, according to an embodiment, a method of treating a subject suffering from or diagnosed with a disease, disorder, or medical condition, such as cancer, comprises administering to the subject an effective amount of at least one compound selected from: compounds of Formula (I), (such as a compound of Table 1), and pharmaceutically acceptable salts of all the foregoing (e.g., by inhibiting or otherwise altering dihydroorotate oxygenase enzyme activity in the subject). In another embodiment, inhibitors of DHODH of the present invention may be used for the treatment of immunological diseases including, but not limited to, autoimmune and inflammatory disorders, e.g. arthritis, inflammatory bowel disease, gastritis, ankylosing spondylitis, ulcerative colitis, pancreatitis, Crohn’s disease, celiac disease, multiple sclerosis, systemic lupus erythematosus, lupus nephritis, rheumatic fever, gout, organ or transplant rejection, chronic allograft rejection, acute or chronic graft-versus-host disease, dermatitis including atopic, dermatomyositis, psoriasis, Behcet’s diseases, uveitis, myasthenia gravis, Grave’s disease, Hashimoto thyroiditis, Sjogren’s syndrome, blistering disorders, antibody- mediated vasculitis syndromes, immune-complex vasculitides, allergic disorders, asthma, bronchitis, chronic obstructive pulmonary disease (COPD), cystic fibrosis, pneumonia, pulmonary diseases including edema, embolism, fibrosis, sarcoidosis, hypertension and emphysema, silicosis, respiratory failure, acute respiratory distress syndrome, BENTA disease, berylliosis, and polymyositis. As used herein, unless otherwise noted, the term “affect” or “affected” (when referring to a disease, disorder, or medical condition that is affected by the inhibition or alteration of DHODH enzymatic activity) includes a reduction in the frequency and / or severity of one or more symptoms or manifestations of said disease, syndrome, condition or disorder; and / or includes the prevention of the development of one or more symptoms or manifestations of said disease, syndrome, condition or disorder or the development of the disease, condition, syndrome or disorder. An additional embodiment of the invention provides a method of treatment of cancer comprising administering to a subject in need thereof, a therapeutically effective amount of a compound of Formula (I), or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer thereof. According to an embodiment, the cancer is selected from but not limited to, lymphomas, leukemias, carcinomas, and sarcomas. An additional embodiment of the invention provides the use of a compound of Formula (I), or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer thereof, for the treatment of one or more cancer types. According to particular embodiments, the uses and methods of treatment described herein are directed to the treatment of cancer, wherein the cancer is selected from but not limited to: leukemias including but not limited to acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), (acute) T-cell leukemia, acute monocytic leukemia, acute promyelocytic leukemia (APL), bisphenotypic B myelomonocytic leukemia, chronic myeloid leukemia (CML), chronic myelomonocytic leukemia (CMML), large granular lymphocytic leukemia, plasma cell leukemia, and also myelodysplastic syndrome (MDS), which can develop into an acute myeloid leukemia, lymphomas including but not limited to AIDS-related lymphoma, Hodgkin lymphoma, non-Hodgkin's lymphoma (NHL), T-non-Hodgkin lymphoma (T-NHL), subtypes of NHL such as Diffuse Large Cell Lymphoma (DLBCL), activated B-cell DLBCL, germinal center B-cell DLBCL, double-hit lymphoma and double-expressor lymphoma; anaplastic large cell lymphoma, marginal B cell lymphoma and primary mediastinal B-cell lymphoma, immunoblastic large cell lymphoma, Burkitt lymphoma, follicular lymphoma, hairy cell leukemia, Hodgkin's disease, mantle cell lymphoma (MCL), lymphoplasmatic lymphoma, precursor B -lymphoblastic lymphoma, lymphoma of the central nervous system, small lymphocytic lymphoma (SLL) and chronic lymphocytic leukemia (CLL); T-cell NHL such as precursor T- lymphoblastic lymphoma/leukemia, peripheral T-cell lymphoma (PTCL), cutaneous T-cell lymphoma (CTCL), angioimmunoblastic T-cell lymphoma, extranodal natural killer T-cell lymphoma, enteropathy type T-cell lymphoma, subcutaneous panniculitis-like T-cell lymphoma, anaplastic large cell lymphoma sarcomas including but not limited to sarcoma of the soft tissue, gliosarcoma, osteosarcoma, malignant fibrous histiocytoma, lymphosarcoma, and rhabdomyosarcoma; and other cancers, such as solid tumors, including but not limited to breast cancer, colorectal carcinoma, gastric cancer, gliosarcoma, head & neck cancer, hepatocellular carcinoma, lung cancer, multiple myeloma, neuroblastoma, ovarian cancer, pancreatic cancer, prostate cancer, renal cell carcinoma and sarcoma. In an embodiment, cancers that may benefit from a treatment with inhibitors of DHODH of the present invention include, but are not limited to, lymphomas, leukemias, carcinomas, and sarcomas, e.g. non-Hodgkin’s lymphoma, diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), follicular lymphoma (FL), marginal zone lymphoma, T-cell lymphoma, Hodgkin’s lymphoma, Burkitt’s lymphoma, multiple myeloma, brain (gliomas), glioblastomas, breast cancer, colorectal/colon cancer, prostate cancer, lung cancer including non-small-cell, gastric cancer, endometrial cancer, melanoma, pancreatic cancer, liver cancer, kidney cancer, squamous cell carcinoma, ovarian cancer, sarcoma, osteosarcoma, thyroid cancer, bladder cancer, head & neck cancer, testicular cancer, Ewing’s sarcoma, rhabdomyosarcoma, medulloblastoma, neuroblastoma, cervical cancer, renal cancer, urothelial cancer, vulval cancer, esophageal cancer, salivary gland cancer, nasopharangeal cancer, buccal cancer, cancer of the mouth, and GIST (gastrointestinal stromal tumor). In another embodiment of the present invention, the compounds of the present invention may be employed in combination with one or more other medicinal agents, more particularly with one or more anti-cancer agents, e.g. chemotherapeutic, anti-proliferative or immunomodulating agents, or with adjuvants in cancer therapy, e.g. immunosuppressive or anti- inflammatory agents. Additional non-limiting examples of anti-cancer agents that may be administered in combination with a compound of the present invention include biologic compounds, such as monoclonal antibodies (e.g., that mediate effector function upon binding to cancer cell-associated antigens, or block interaction of a receptor expressed on cancer cells with a soluble or cell bound ligand), bispecific antibodies that mediate immune cell redirection, etc. According to an embodiment, a method of treating cancer comprises administering an effective amount of a compound of the present invention (e.g., selected from compounds of Formula (I), such as a compound shown in Table 1, pharmaceutically acceptable salts, isotopes, N-oxides, solvates, and stereoisomers thereof) and an effective amount of one or more additional anti- cancer agents, wherein the method comprises administering the compound of the present invention and the additional anti-cancer agent(s) either simultaneously (e.g., as part of the same pharmaceutical composition) or sequentially. According to an embodiment, a pharmaceutical composition comprises an effective amount of a compound of the present invention (e.g., selected from compounds of Formula (I), such as a compound shown in Table 1, pharmaceutically acceptable salts, isotopes, N-oxides, solvates, and stereoisomers thereof), an effective amount of one or more additional anti-cancer agents, and optionally one or more excipients. An additional embodiment of the invention provides the use of a compound of Formula (I), or pharmaceutically acceptable salts, isotopes, N-oxides, solvates, or stereoisomers thereof, as part of chemotherapeutic regimens for the treatment of cancers, lymphomas and leukemias alone or in combination with classic antitumoral compounds well known by the one skilled in the art. GENERAL SYNTHETIC METHODS Exemplary compounds useful in methods of the invention will now be described by reference to the illustrative synthetic schemes for their general preparation below and the specific examples that follow. Artisans will recognize that, to obtain the various compounds herein, starting materials may be suitably selected so that the ultimately desired substituents will be carried through the reaction scheme with or without protection as appropriate to yield the desired product. Alternatively, it may be necessary or desirable to employ, in the place of the ultimately desired substituent, a suitable group that may be carried through the reaction scheme and replaced as appropriate with the desired substituent. Unless otherwise specified, the variables are as defined above in reference to Formula (I). Reactions may be performed between the melting point and the reflux temperature of the solvent, and preferably between 0 °C and the reflux temperature of the solvent. Reactions may be heated employing conventional heating or microwave heating. Reactions may also be conducted in sealed pressure vessels above the normal reflux temperature of the solvent. Abbreviations used in the instant specification, particularly the schemes and examples, are as follows in Table 2: Table 2.
Figure imgf000027_0001
Figure imgf000028_0001
Figure imgf000029_0001
Figure imgf000030_0001
Figure imgf000031_0003
PREPARATIVE EXAMPLES Exemplary compounds useful in methods of the invention will now be described by reference to the illustrative synthetic schemes for their general preparation below and the specific examples to follow.
Figure imgf000031_0001
According to SCHEME 1, a 1,2,4-triazol-5(4H)-one compound of formula (II), where PG is Bn, is prepared from ethyl 2-(benzyloxy)acetate in three steps. In a first step 2- (benzyloxy)acetohydrazide is prepared by the reaction of ethyl 2-(benzyloxy)acetate with hydrazine hydrate, in a suitable solvent such as EtOH, and the like; at temperatures ranging from 70-85 °C. Reaction of the hydrazide with an isocyanate of formula Ra-NCO, where Ra is C1-6alkyl, in a suitable solvent such as water, and the like; provides the corresponding semicarbazide. Subsequent cyclization of the semicarbazide with a suitable base such as NaOH, in a suitable solvent such as water, provides a compound of formula (II), where PG is Bn. SCHEME 2
Figure imgf000031_0002
According to SCHEME 2, a compound of formula (III), where Y is CH or N, and Ra is C1-6alkyl; is reacted with a Grignard reagent such as MeMgBr, in a suitable solvent such as THF, ether, or a mixture thereof; and the like; at temperatures of about 0 °C, for period of about 2-6 hrs; to provide a compound of formula (IV). A compound of formula (IV), is reacted with a source of tributyltin radical such as hexa‐n‐butylditin; a palladium catalyst such as Pd(PPh3)2Cl2, and the like; in a suitable solvent such as toluene; at a temperature of about 100 ℃; for a period of 12-18 h; to provide a compound of formula (V). SCHEME 3
Figure imgf000032_0001
According to SCHEME 3, a commercially available or synthetically accessible compound of formula (VI), where R4 is as described in claim 1, is reacted in a transition-metal- catalyzed borylation reaction employing conditions known to one skilled in the art. For example, in a preferred method, an aryl or heteroaryl halide compound of formula (VI) where R4 is as described in claim 1, is reacted in cross-coupling reaction of bis(pinacolato)diboron (B2pin2); a palladium catalyst such as Pd(dppf)Cl2, and the like; a base such as KOAc, NaOAc, and the like; in a suitable solvent, such as 1,4-dioxane, DMSO, toluene, and the like; at temperatures of about 100 °C, for a period of 16-24 h; to provide a compound of formula (VII). SCHEME 4
Figure imgf000032_0002
According to SCHEME 4, 2-chloro-5-fluoro-4-iodopyridine; and triazolone of formula (II), where Ra is C1-6alkyl, and PG is a protecting group such as benzyl, para-methoxy benzyl, TBDPS, TIPS, TBS, and the like, are reacted employing copper catalyzed arylation conditions to provide a compound of formula (VIII). For example, reaction of 2-chloro-5-fluoro-4- iodopyridine with a compound of formula (II); in the presence of a Cu(I) or Cu(II) salt such as CuI; with or without an additive such as KI; a ligand such as trans-N,N′-dimethylcyclohexane- 1,2-diamine, N,N’-dimethylglycine, 2‐((2,6‐dimethylphenyl)amino)‐2‐oxoacetic acid, and the like; a base such as Cs2CO3, K2CO3, K3PO4, K2HPO4, KHCO3, Na2CO3, NaHCO3, and the like; in a suitable solvent such as dioxane, and the like; at temperatures ranging from 90 to 110 °C; for a period of about 16 to 24 hours; provides a compound of formula (VIII). Pd-catalyzed arylation of an aldehyde such as 3-methylbutanal with a compound of formula (VIII); a transition metal catalysts such as Pd(PPh3)2Cl2, Pd(OAc)2, and the like; preferably Pd(OAc)2; a ligand such as (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (rac-BINAP); a base such as Cs2CO3, LHMDS, NaOtBu, K3PO4, and the like; in a suitable solvent such as toluene, THF, DMF, 1,4- dioxane, or a mixture thereof; at temperatures ranging from 80-150 ºC, employing microwave or conventional heating; for a period of 0.5 h to 18 h; affords a compound of formula (IX). Piperidine-catalyzed Knoevenagel condensation reaction between diethyl malonate and a compound of formula (IX) affords a compound of formula (X). For example, reaction of a compound of formula (IX), with diethyl malonate; acetic acid; in a suitable solvent such as ethanol, and the like; at a temperature of about 90 °C; for a period of about 12 hours; provides a compound of formula (X). SCHEME 5
Figure imgf000033_0001
According to SCHEME 5, 2-chloro-5-fluoro-4-iodopyridine is reacted in a Pd-catalyzed arylation reaction with diphenyl methanimine; employing a palladium catalyst such as Pd2(dba)3, and the like; a suitable ligand such as 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (XantPhos), and the like; a base such as Cs2CO3, LHMDS, NaOtBu, K3PO4, and the like; in a suitable solvent such as toluene, THF, DMF, dioxane, toluene, or a mixture thereof; at temperatures ranging from 80-150 ºC, employing microwave or conventional heating; for a period of 0.5 h to 18 h; to provide 2-chloro-N-(diphenylmethylene)-5-fluoropyridin-4-amine. Pd-catalyzed arylation of an aldehyde such as 3-methylbutanal with 2-chloro-N- (diphenylmethylene)-5-fluoropyridin-4-amine, employing methods previously described, affords 2-(4-((diphenylmethylene)amino)-5-fluoropyridin-2-yl)-3-methylbutanal. Piperidine- catalyzed Knoevenagel condensation reaction between diethyl malonate and 2-(4- ((diphenylmethylene)amino)-5-fluoropyridin-2-yl)-3-methylbutanal, employing conditions previously described, affords diethyl 2-(2-(4-((diphenylmethylene)amino)-5-fluoropyridin-2-yl)- 3-methylbutylidene)malonate.
Figure imgf000034_0001
X), is achieved employing TEA; in a suitable solvent such as DMA, and the like; at temperatures of about 140 °C; for a period of about 20 to 36 hours; to afford a compound of formula (XI). In a similar fashion, diethyl 2-(2-(4-((diphenylmethylene)amino)-5-fluoropyridin-2-yl)-3- methylbutylidene)malonate is cyclized thermally to afford a compound of formula (XII), where R3 is F. SCHEME 7
Figure imgf000035_0001
According to SCHEME 7, an imine compound of formula (XII), where R3 is F, is cleaved employing methods known to one skilled in the art to provide a compound of formula (XIII). For example, treatment of a compound of formula (XII), with HCl in 1,4-dioxane, and the like; at room temperature for a period of 16 h, affords a compound of formula (XIII). A compound of formula (XIII) is reacted under diazotization conditions known to one skilled in the art. For example, a compound of formula (XIII), is reacted with tert-butyl nitrite or other nitrite reagents; and CuBr2; at temperatures of about 70 °C; for a period of about 6 h; to provide a compound of formula (XIV), where R1 is CH(CH3)2. SCHEME 8
Figure imgf000035_0002
According to Scheme 8, a compound of formula (XIV), where R1 is CH(CH3)2, and R3 is F, undergoes a Stille cross coupling reaction, with an alkyl stannane of formula (V), where Y is N or CH, and Ra is C1-6alkyl, employing conditions known to one skilled in the art, to provide a compound of formula (XV), and a compound of formula (XVI). For example, a compound of formula (XIV) is reacted with a commercially available or synthetically accessible organostannane compound of formula (V), where Y is CH or N, and Ra is C1-6alkyl, using a palladium catalyst such as Pd(PPh3)3Cl2, Pd(dppf)Cl2, and the like; in a suitable solvent such as 1,4-dioxane, toluene, and the like; at refluxing temperatures; to provide a compound of formula (XV). Subsequent hydrolysis of a compound of formula (XV), employing conditions known to one skilled in the art, such as using LiOH.H2O in a suitable solvent such as MeOH, THF, or a mixture thereof; affords a compound of formula (XVI). The Stille coupling, may also provide a mixture of the ester and acid compounds of formula (XV) and (XVI). Hydrolysis of the mixture of acid and ester compounds, employing conditions previously described, affords a compound of formula (XVI). previously described, affords a compound of formula (XVI). SCHEME 9
Figure imgf000036_0001
According to SCHEME 9, halogenation of a compound of formula (XVI) is achieved employing a brominating agent such as Br2, in a suitable solvent such as pyridine, at 100 °C, for a period of 2 hours, to afford a compound of formula (XVII), where HAL is Br. A compound of formula (XVII); is reacted under Suzuki coupling conditions known to one skilled in the art with a commercially available or synthetically accessible suitably substituted compound of formula (VII), to provide a compound of Formula (I). SCHEME 10
Figure imgf000036_0002
According to SCHEME 10, a compound of formula (XI) is hydrolyzed using conditions known to one skilled in the art. For example, treatment of a compound of formula (XI) with LiOH.H2O in a suitable solvent such as MeOH, THF, water or a mixture thereof; affords a compound of formula (XVIII). Subsequent decarboxylation under acidic conditions; such as 1 M HCl in water and heating at 90 °C; followed by halogenation using conditions known to one skilled in the art; such as NBS in a suitable solvent such as DMF; affords a compound of formula (XIX). SCHEME 11
Figure imgf000037_0001
A compound of formula (XIX); is reacted under Suzuki coupling conditions known to one skilled in the art with a commercially available or synthetically accessible suitably substituted compound of formula (VII), to provide a compound of formula (XX). In a preferred method, a compound of formula (XIX) and a compound of formula (VII) are treated with XPhos Pd G3 and Cs2CO3 in a mixture of 1,4-dioxane and water at 100 °C for a period of 1 h. Subsequent deprotection employing established methodologies, such as those described in T. W. Greene and P. G. M. Wuts, “Protective Groups in Organic Synthesis,” 3 ed., John Wiley & Sons, 1999), provides a compound of Formula (I). For example, compound of formula (XX), where R3 is F, Ra is C1-6alkyl and PG is Bn, is deprotected employing conditions known to one skilled in the art, preferably with BCl3 in a suitable solvent such as DCM, and the like. Compounds of Formula (I) may be converted to their corresponding salts using methods known to one of ordinary skill in the art. For example, an amine of Formula (I) is treated with trifluoroacetic acid, HCl, or citric acid in a solvent such as Et2O, CH2Cl2, THF, MeOH, chloroform, or isopropanol to provide the corresponding salt form. Alternately, trifluoroacetic acid or formic acid salts are obtained as a result of reverse phase HPLC purification conditions. Crystalline forms of pharmaceutically acceptable salts of compounds of Formula (I) may be obtained in crystalline form by recrystallization from polar solvents (including mixtures of polar solvents and aqueous mixtures of polar solvents) or from non-polar solvents (including mixtures of non-polar solvents). Where the compounds according to this invention have at least one chiral center, they may accordingly exist as enantiomers. Where the compounds possess two or more chiral centers, they may additionally exist as diastereomers. It is to be understood that all such isomers and mixtures thereof are encompassed within the scope of the present invention. Compounds prepared according to the schemes described above may be obtained as single forms, such as single enantiomers, by form-specific synthesis, or by resolution. Compounds prepared according to the schemes above may alternately be obtained as mixtures of various forms, such as racemic (1:1) or non-racemic (not 1:1) mixtures. Where racemic and non-racemic mixtures of enantiomers are obtained, single enantiomers may be isolated using conventional separation methods known to one of ordinary skill in the art, such as chiral chromatography, recrystallization, diastereomeric salt formation, derivatization into diastereomeric adducts, biotransformation, or enzymatic transformation. Where regioisomeric or diastereomeric mixtures are obtained, as applicable, single isomers may be separated using conventional methods such as chromatography or crystallization. The following specific examples are provided to further illustrate the invention and various preferred embodiments. EXAMPLES In obtaining the compounds described in the examples below and the corresponding analytical data, the following experimental and analytical protocols were followed unless otherwise indicated. Unless otherwise stated, reaction mixtures were magnetically stirred at room temperature (rt) under a nitrogen atmosphere. Where solutions were “dried,” they were generally dried over a drying agent such as Na2SO4 or MgSO4. Where mixtures, solutions, and extracts were “concentrated”, they were typically concentrated on a rotary evaporator under reduced pressure. Normal-phase silica gel chromatography (FCC) was performed on silica gel (SiO2) using prepacked cartridges. Preparative reverse-phase high performance liquid chromatography (RP HPLC) was performed on either: Preparative supercritical fluid high performance liquid chromatography (SFC) was performed either on a Thar 80 Prep-SFC system, or Waters 80Q Prep-SFC system from Waters. The ABPR was set to 100bar to keep the CO2 in SF conditions, and the flow rate may verify according to the compound characteristics, with a flow rate ranging from 50g/min to 70g/min. The column temperature was ambient temperature Mass spectra (MS) were obtained on a SHIMADZU LCMS-2020 MSD or Agilent 1200\G6110A MSD using electrospray ionization (ESI) in positive mode unless otherwise indicated. Calculated (calcd.) mass corresponds to the exact mass. Nuclear magnetic resonance (NMR) spectra were obtained on Bruker model AVIII 400 spectrometers. Definitions for multiplicity are as follows: s = singlet, d = doublet, t= triplet, q = quartet, dd = doublet of doublets, ddd = doublet of doublet of doublets, td = triplet of doublets, dt = doublet of triplets, spt = septet, quin = quintet, m = multiplet, br = broad. It will be understood that for compounds comprising an exchangeable proton, said proton may or may not be visible on an NMR spectrum depending on the choice of solvent used for running the NMR spectrum and the concentration of the compound in the solution. Chemical names were generated using ChemDraw Ultra 17.1 (CambridgeSoft Corp., Cambridge, MA) or OEMetaChem V1.4.0.4 (Open Eye). Intermediate 1: 2-(1-Methyl-4-(tributylstannyl)-1H-imidazol-2-yl)propan-2-ol.
Figure imgf000039_0001
Step A.2-(4-Bromo-1-methyl-1H-imidazol-2-yl)propan-2-ol. To a solution of methyl 4-bromo- 1-methyl-1H-imidazole-2-carboxylate (2 g, 9.1 mmol) in THF (40 mL) at 0 °C was added MeMgBr (3M in diethyl ether, 15 mL, 46 mmol) dropwise. The resulting reaction mixture was stirred at 0 °C for 2 h. The mixture was slowly poured into sat. aq. NH4Cl (30 mL) and extracted with DCM (30 mL × 2). The combined organic layers were dried over Na2SO4, filtered, and concentrated. The residue was purified by column chromatography (SiO2, gradient elution: 0 – 60% ethyl acetate in petroleum ether) to give the title compound as a white solid (1.72 g, 86% yield). MS (ESI): mass calcd. for C7H11BrN2O, 218.0; m/z found, 219.1 [M+H]+.1H NMR (400 MHz, CDCl3) δ 6.76 (s, 1H), 3.81 (s, 3H), 2.37 (s, 1H), 1.65 (s, 6H) ppm. Step B.2-(1-Methyl-4-(tributylstannyl)-1H-imidazol-2-yl)propan-2-ol. To a mixture of 2-(4- bromo-1-methyl-1H-imidazol-2-yl)propan-2-ol (500 mg, 2.2 mmol), Pd(Ph3P)2Cl2 (155 mg, 221 μmol) in toluene (17.5 mL) was added 1,1,1,2,2,2-hexabutyldistannane (2.94 g, 5.1 mmol). Then the resulting mixture was stirred at 100 °C for 16 hours under N2. The reaction mixture was filtered and used in the next step directly (1 g of crude compound in 17.5 mL toluene). Intermediate 2: 2-(1-Methyl-3-(tributylstannyl)-1H-1,2,4-triazol-5-yl)propan-2-ol.
Figure imgf000040_0001
Step A.2-(3-Bromo-1-methyl-1H-1,2,4-triazol-5-yl)propan-2-ol. To a solution of 3-bromo-1- methyl-1H-1,2,4-triazole-5-carboxylate (8.0 g, 35 mmol) in THF (160 mL) at 0 °C was added MeMgBr (3 M in diethyl ether, 78 mL, 233 mmol) dropwise. The resulting reaction mixture was stirred at 0 °C for 4 h. The mixture was slowly poured into sat. aq. NH4Cl (200 mL) and extracted with DCM (200 mL × 2). The combined organic layers were dried over Na2SO4, filtered, and concentrated. The residue was purified by column chromatography (SiO2, gradient elution: 0 – 50% ethyl acetate in petroleum ether) to give the title compound as a white solid (4.7 g, 59% yield). MS (ESI): mass calcd. for C6H10BrN3O, 219.0; m/z found, 220.0 [M+H]+.1H NMR (400 MHz, CDCl3) δ 4.05 (s, 3H), 2.25 (s, 1H), 1.69 (s, 6H) ppm. Step B.2-(1-Methyl-3-(tributylstannyl)-1H-1,2,4-triazol-5-yl)propan-2-ol. To a mixture of 2-(3- bromo-1-methyl-1H-1,2,4-triazol-5-yl)propan-2-ol (500 mg, 2.2 mmol), Pd(Ph3P)2Cl2 (155 mg, 216 μmol) in toluene (17.5 mL) was added 1,1,1,2,2,2-hexabutyldistannane (2.24 g, 3.8 mmol). Then the resulting mixture was stirred at 100 °C for 16 hours under N2. The reaction mixture was filtered and used into next step directly (1 g of crude compound in 17.5 mL toluene). Intermediate 3: 5-((Benzyloxy)methyl)-4-ethyl-2,4-dihydro-3H-1,2,4-triazol-3-one.
Figure imgf000040_0002
Step A. 2-(Benzyloxy)acetohydrazide. To a solution of ethyl 2-(benzyloxy)acetate (55 g, 283.17 mmol) in EtOH (500 mL) was added NH2NH2•H2O (28.3 g, 566 mmol, 27.5 mL). The reaction mixture was heated at 78 °C for 6 h. The reaction mixture was concentrated under reduced pressure to afford the title product (52 g, crude) as a colorless oil, which was used directly in the next step without further purification. Step B.3-((Benzyloxy)methyl)-4-ethyl-1H-1,2,4-triazol-5(4H)-one. To a solution of 2- (benzyloxy)acetohydrazide (52 g, 288 mmol) in H2O (500 mL) was added dropwise isocyanatoethane (25.1 g, 346 mmol, 27.9 mL) at 0 °C. After the addition was complete, the mixture was stirred at 25°C for 12 hr. To the mixture was added H2O (20 mL), and an aqueous solution (120 mL) of NaOH (57.7 g, 1.44 mol). The mixture was stirred at 95 °C for 12 hr. The reaction mixture was cooled to rt, then quenched with HCl (12 M) at 0 °C and adjusted to pH 6. The solid was filtered and dried under reduced pressure to afford the title compound as a white solid (61 g, 91% yield). 1H NMR (400 MHz, CDCl3) δ 9.23 - 9.09 (m, 1H), 7.41 - 7.31 (m, 5H), 4.58 - 4.53 (m, 2H), 4.45 - 4.42 (m, 2H), 3.82 - 3.75 (m, 2H), 1.33 - 1.29 (m, 3H) ppm. Intermediate 4: 3-Methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5-(trifluoromethyl)- 1H-pyrazole.
Figure imgf000041_0001
To the mixture of 4-bromo-3-methyl-5-(trifluoromethyl)-1H-pyrazole (1.0 g, 4.4 mmol) in 1,4- dioxane (5 mL) was added B2Pin2 (4.4 g, 17.5 mmol), KOAc (2.6 g, 26.2 mmol) and Pd(dppf)Cl2 (320 mg, 437 μmol) underN2. The resulting mixture was charged with N2 three times and stirred at 100 °C overnight. The reaction mixture was filtered and concentrated under reduced pressure. The crude was purified by preparative reverse phase HPLC (Stationary phase: Boston Uni C18 40 × 150 × 5um; Mobile phase: water(0.225% FA) (A) - MeCN (B), gradient elution: 45 - 75% B in A over 7.7 min, flow rate: 60 mL/min) to give the title compound (71 mg, 6% yield, 100% purity) as yellow solid. MS (ESI): mass calcd. for C11H16BF3N2O2, 276.1; m/z found, 277.1 [M+H]+.1H NMR (400 MHz, CDCl3) δ 2.50 (s, 3H), 1.33 (s, 12H); 19F NMR (376 MHz, CDCl3) δ -58.40 - -62.97 (1F) ppm. Intermediate 5: 5-Chloro-3-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole.
Figure imgf000041_0002
Step A.4-Bromo-3-chloro-5-methyl-1H-pyrazole. To a mixture of 3-chloro-5-methyl-1H- pyrazole (2.0 g, 17 mmol) in DCM (30 mL) was added NBS (3.1 g, 17 mmol). The resulting mixture was stirred at room temperature overnight. To the mixture was added DCM (80 mL), washed with sat. aq. Na2S2O3 (80 mL) and brine (80 mL). The organic layer was dried over Na2SO4, filtered and concentrated under vacuum. The residue was purified column chromatography (SiO2, 220 nm, gradient elution: 0-100% DCM in petroleum ether, then 0-10% MeOH in DCM) to give the title compound (3.3 g, 98% yield) as light yellow solid. MS (ESI): mass calcd. for C4H4BrClN2, 193.9; m/z found, 196.6 [M+H]+.1H NMR (400 MHz, CDCl3) δ 11.67 (br s, 1H), 2.38 (s, 3H) ppm. Step B.3-Chloro-5-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole. To a mixture of 4-bromo-3-chloro-5-methyl-1H-pyrazole (10.1 g, 52 mmol) in 1,4-dioxane (132 mL) was added 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1,3,2-dioxaborolane) (53 g, 207 mmol) and KOAc (30.5 g, 311 mmol). The mixture was charged with N2. Pd(dppf)Cl2.CH2Cl2 (4.2 g, 5.2 mmol) was added under N2. The mixture was stirred at 100 °C overnight then cooled down to rt. The mixture was filtered through a pad of Celite® and the solid was rinsed with ethyl acetate (900 mL). The filtrate was concentrated under vacuum. The residue was purified by column chromatography (SiO2, 220 nm, gradient elution: 0-100% DCM in petroleum ether, then 0-10% MeOH in DCM) to give the crude compound (8.8 g crude) as brown sticky solid. The crude product was further purified by preparative reversed phase HPLC (Stationary phase: YMC-Triart Prep C18, 10 µm, 250 x 50 mm; Mobile phase: water(0.225% FA) (A) - MeCN (B), gradient elution: 5 - 59% B in A over 20 min, flow rate: 100 mL/min) to give the title compound (2113 mg, 16% yield) as a white powder.MS (ESI): mass calcd. for C10H16BClN2O2, 242.1; m/z found, 243.0 [M+H]+.1H NMR (400 MHz, DMSO-d6) δ 12.91 (br s, 1H), 2.31 (s, 3H), 1.25 (s, 12H) ppm. Intermediate 6: 2-Chloro-4-methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine.
Figure imgf000042_0001
To a mixture of 3-bromo-2-chloro-4-methylpyridine (1.0 g, 4.8 mmol) in 1,4-dioxane (40 mL) was added B2Pin2 (1.2 g, 4.8 mmol), Pd(dppf)Cl2 (354 mg, 484 μmol) and KOAc (1.4 g, 14.5 mmol). The resulting mixture was stirred at 100 °C for 12 hours under N2. The reaction mixture was filtered and concentrated under vacuum. The residue was purified by column chromatography (40 g, 0 - 10% ethyl acetate in petroleum ether) to give the title compound (630 mg, 50% yield) as a white solid. MS (ESI): mass calcd. for C12H17BClNO2, 253.10; m/z found, 254.00 [M+H]+.1H NMR (400 MHz, CDCl3) δ 8.22 (d, J = 5.0 Hz, 1H), 7.00 (d, J = 5.0 Hz, 1H), 2.38 (s, 3H), 1.42 (s, 12H) ppm. Intermediate 7: Ethyl 8-bromo-7-fluoro-1-isopropyl-4-oxo-4H-quinolizine-3-carboxylate.
Figure imgf000043_0001
Step A.2-Chloro-N-(diphenylmethylene)-5-fluoropyridin-4-amine. To a mixture of 2-chloro-5- fluoro-4-iodopyridine (20.0 g, 77.7 mmol), diphenyl methanimine (15.5 g, 85.5 mmol), Pd2(dba)3 (7.1 g, 7.8 mmol), Xantphos (9.0 g, 15.5 mmol), Cs2CO3 (38 g, 117 mmol) in toluene (300 mL) was stirred at 100 °C for 16 hours under N2. The reaction mixture was filtered, and the filtrate was concentrated under reduced pressure. The crude was purified by column chromatography (SiO2, gradient elution: 0 – 5% ethyl acetate in petroleum ether) to give the title compound (15.0 g, 59% yield) as a yellow solid. MS (ESI): mass calcd. for C18H12ClFN2, 310.1; m/z found, 311.1 [M+H]+. 1H NMR (400 MHz, CDCl3) δ 7.99 (d, J = 1.8 Hz, 1H), 7.90 - 7.65 (m, 2H), 7.51 - 7.30 (m, 6H), 7.18 (br s, 2H), 6.76 (d, J = 5.7 Hz, 1H); 19F NMR (376 MHz, CDCl3) δ -143.05 (1F) ppm. Step B.2-(4-((Diphenylmethylene)amino)-5-fluoropyridin-2-yl)-3-methylbutanal. To a mixture of 2-chloro-N-(diphenylmethylene)-5-fluoropyridin-4-amine (16 g, 48.9 mmol), BINAP (4.3 g, 6.9 mmol), Pd(OAc)2 (0.77 g, 3.4 mmol) and Cs2CO3 (32 g, 98 mmol) in 1,4- dioxane (240 mL) was added 3-methylbutanal (21.1 g, 245 mmol). The resulting mixture was stirred at 90 °C for 12 hours under N2. The reaction mixture was filtered, and the filtrate was concentrated under reduced pressure. The crude was purified by column chromatography (SiO2, gradient elution: 0 – 6% ethyl acetate in petroleum ether) to give the title compound (17.2 g, 95% yield) as yellow oil. MS (ESI): mass calcd. for C23H21FN2O, 360.2; m/z found, 361.0 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.74 (d, J = 3.8 Hz, 1H), 8.23 (d, J = 2.0 Hz, 1H), 7.79 (br d, J = 6.5 Hz, 2H), 7.60 - 7.30 (m, 6H), 7.15 (br s, 2H), 6.50 (d, J = 6.5 Hz, 1H), 3.12 (dd, J = 3.5, 9.3 Hz, 1H), 2.39 (m, 1H), 0.95 (d, J = 6.5 Hz, 3H), 0.57 (d, J = 6.8 Hz, 3H); 19F NMR (376 MHz, CDCl3) δ -143.42 (1F) ppm. Step C. Diethyl 2-(2-(4-((diphenylmethylene)amino)-5-fluoropyridin-2-yl)-3- methylbutylidene)malonate. To a solution of 2-(4-((diphenylmethylene)amino)-5-fluoropyridin- 2-yl)-3-methylbutanal (17.2 g, 46.3 mmol), diethyl malonate (14.8 g, 93 mmol), AcOH (8.9 g, 148 mmol) in EtOH (280 mL) was added piperidine (6.3 g, 74 mmol). Then the resulting mixture was stirred at 90 °C for 12 hours. The reaction mixture was diluted with H2O (300 mL), extracted with ethyl acetate (100 mL x 3). The combined organic layers was dried over Na2SO4, filtered and concentrated under reduced pressure. The crude was purified by column chromatography (SiO2, gradient elution: 0 – 10% ethyl acetate in petroleum ether) to give the title compound (29.8 g, 99% yield) as yellow oil. MS (ESI): mass calcd. for C28H25FN2O3, 502.2; m/z found, 503.1 [M+H]+.1H NMR (400 MHz, CDCl3) δ 8.23 (d, J = 2.0 Hz, 0.2H), 8.18 (d, J = 2.0 Hz, 1H), 7.79 (br s, 2.4H), 7.61 - 7.04 (m, 12.7H), 6.66 (d, J = 6.5 Hz, 0.2H), 6.49 (d, J = 6.3 Hz, 1H), 5.74 (d, J = 10.3 Hz, 0.2H), 4.31 - 4.27 (m, 1.2H), 4.25 - 4.22 (m, 4H), 3.33 (dd, J = 9.7, 10.9 Hz, 1H), 2.81 - 2.69 (m, 0.2H), 1.36 - 1.29 (m, 7.2H), 0.97 - 0.94 (m, 1.4H), 0.87 (d, J = 6.8 Hz, 3H), 0.55 (d, J = 6.8 Hz, 3H); 19F NMR (376 MHz, CDCl3) δ -139.63 -150.88 (1F) ppm. Step D. Ethyl 8-((diphenylmethylene)amino)-7-fluoro-1-isopropyl-4-oxo-4H-quinolizine-3- carboxylate. To a solution of diethyl 2-(2-(4-((diphenylmethylene)amino)-5-fluoropyridin-2-yl)- 3-methyl butylidene)malonate (29.8 g, 45.7 mmol) in DMA (380 mL) was added Et3N (76.2 mL, 548 mmol), Then the resulting mixture was stirred at 140 °C for 36 hours. The reaction mixture was diluted with ethyl acetate (500 mL), washed with H2O (300 mL x 3). The combined organic layers was dried over Na2SO4, filtered and concentrated under reduced pressure. The crude was purified by column chromatography (SiO2, gradient elution: 0 – 70% ethyl acetate in petroleum ether) to give the title compound (17.2 g, 66% yield, 80% purity) as a red solid. MS (ESI): mass calcd. for C30H31FN2O4, 456.2; m/z found, 457.1 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.35 (d, J = 6.8 Hz, 1H), 8.21 (s, 1H), 7.84 - 7.32 (m, 10H), 7.03 (d, J = 7.5 Hz, 1H), 4.42 (q, J = 7.0 Hz, 2H), 1.42 (t, J = 7.2 Hz, 3H), 1.21 (d, J = 6.8 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ - 142.10 (1F) ppm. Step E. Ethyl 8-amino-7-fluoro-1-isopropyl-4-oxo-4H-quinolizine-3-carboxylate. To a solution of ethyl 8-((diphenylmethylene)amino)-7-fluoro-1-isopropyl-4-oxo-4H- quinolizine-3- carboxylate(17.2 g, 30.1 mmol) in DCM (100 mL) was added HCl (4 M solution in 1,4-dioxane, 215 mL). Then the resulting mixture was stirred at room temperature for 2 hours. The reaction mixture was concentrated under reduced pressure to give a yellow solid. The yellow solid was diluted with ethyl acetate (50 mL), and stirred at room temperature for 15 min. Then the mixture was filtered, and the filter cake was dissolved in MeOH (100 mL), diluted with ethyl acetate (300 mL). Then sat. aq. Na2CO3 (200 mL) was added, the mixture was stirred for 0.5 hour. The organic layers were separated and extracted with ethyl acetate (300 mL x 3). The combined organic layers was dried over Na2SO4, filtered and concentrated under reduced pressure to give the title compound (8.5 g, quantitative) as a yellow solid. MS (ESI): mass calcd. for C15H17FN2O3, 292.1; m/z found, 293.1 [M+H]+.1H NMR (400 MHz, DMSO-d6) δ 9.16 (d, J = 8.3 Hz, 1H), 7.81 (s, 1H), 7.74 - 7.52 (m, 2H), 7.02 (d, J = 8.5 Hz, 1H), 4.17 (q, J = 7.0 Hz, 2H), 3.01 (m, 1H), 1.30 - 1.18 (m, 9H); 19F NMR (376 MHz, DMSO-d6) δ -149.20 (1F) ppm. Step F. Ethyl 8-bromo-7-fluoro-1-isopropyl-4-oxo-4H-quinolizine-3-carboxylate. To a mixture of tert-butyl nitrite (2.7 g, 26.0 mmol) and CuBr2 (4.5 g, 20.2 mmol) in MeCN (80 mL) was added ethyl 8-amino-7-fluoro-1-isopropyl-4-oxo-4H- quinolizine-3-carboxylate (4.3 g, 14.4 mmol). The resulting mixture was stirred at 70 °C for 16 hours. The reaction mixture was poured into sat. aq. Na2CO3 (60 mL), extracted with ethyl acetate (300 mL x 3). The combined organic layers was dried over Na2SO4, filtered and concentrated under reduced pressure to give the title compound (3.6 g, 69% yield) as a yellow solid. MS (ESI): mass calcd. for C15H15BrFNO3, 355.0; m/z found, 356.0 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.41 (d, J = 5.3 Hz, 1H), 8.40 (s, 1H), 8.10 (d, J = 6.5 Hz, 1H), 4.45 (q, J = 7.0 Hz, 2H), 3.36 - 3.13 (m, 1H), 1.44 (t, J = 7.0 Hz, 3H), 1.36 (d, J = 6.8 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ -128.83 (1F) ppm. Intermediate 8: 3-Bromo-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)- 1-isopropyl-4H-quinolizin-4-one.
Figure imgf000046_0001
Step A. Ethyl 7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1- isopropyl-4-oxo-4H-quinolizine-3-carboxylate and 7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1- methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-4-oxo-4H-quinolizine-3-carboxylic acid. To a mixture of 2-(1-methyl-3-(tributylstannyl)-1H-1,2,4-triazol-5-yl)propan-2-ol (Intermediate 2, 875 mg of crude in 17.5 mL toluene ) in 1,4-dioxane (17.5 mL) was added ethyl 8-bromo-7-fluoro-1- isopropyl-4-oxo-4H-quinolizine-3-carboxylate (Intermediate 7, 500 mg, 1.4 mmol) and Pd(Ph3P)2Cl2 (99 mg, 140.0 μmol). The resulting mixture was stirred at 100 °C for 18 hours under N2. The reaction mixture was purified by column chromatography (SiO2, gradient elution: 0 – 100% ethyl acetate in petroleum ether) to give the mixture (230 mg) as a yellow solid. MS (ESI): mass calcd. for C21H25FN4O4, 416.2; m/z found, 417.1 [M+H]+ and C19H21FN4O4, 388.2; m/z found, 389.1 [M+H]+.1H NMR (400 MHz, CDCl3) δ 14.09 (br s, 0.4H), 9.36 (d, J = 7.0 Hz, 0.4H), 9.39 - 9.33 (m, 1H), 9.20 (d, J = 7.5 Hz, 0.4H), 8.71 (d, J = 6.8 Hz, 0.4H), 8.53 (d, J = 7.0 Hz, 1H), 8.37 (s, 1H), 4.47 (q, J = 7.2 Hz, 2H), 4.22 (s, 1.3H), 4.01 (s, 3H), 3.71 (br s, 1H), 3.57 - 3.38 (m, 1.4H), 2.61 (br s, 0.4H), 1.80 (s, 2.7H), 1.77 (s, 6H), 1.50 - 1.38 (m, 12H); 19F NMR (376 MHz, CDCl3) δ -130.06 (1F), -132.59 (1F) ppm. Step B.7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-4- oxo-4H-quinolizine-3-carboxylic acid. To a mixture of ethyl 7-fluoro-8-(5-(2-hydroxypropan-2- yl)-1-methyl-1H-1,2,4-triazol-3-yl) -1-isopropyl-4-oxo-4H-quinolizine-3-carboxylate and 7- fluoro-8-(5-(2-hydroxypropan-2-yl) -1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-4-oxo-4H- quinolizine-3-carboxylic acid (230 mg) in MeOH/THF (v/v, 1/1, 3 mL) was added LiOH.H2O (63 mg, 1.50 mmol) in H2O (1.5 mL). Then the resulting mixture was stirred at room temperature for 12 hours. The reaction mixture was concentrated under reduced pressure to give the title compound (220 mg, crude) as yellow solid. MS (ESI): mass calcd. for C19H21FN4O4, 388.2; m/z found, 389.1 [M+H]+.1H NMR (400 MHz, DMSO-d6) δ 15.18 - 12.74 (m, 1H), 9.42 (d, J = 7.0 Hz, 1H), 8.69 (d, J = 7.0 Hz, 1H), 8.33 (s, 1H), 5.86 (s, 1H), 4.17 (s, 3H), 3.51 (m, 1H), 1.63 (s, 6H), 1.35 (d, J = 6.8 Hz, 6H); 19F NMR (376 MHz, DMSO-d6) δ -130.59 (1F) ppm. Step C.3-Bromo-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1- isopropyl-4H-quinolizin-4-one. The mixture of 7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl- 1H-1,2,4-triazol-3-yl)-1- isopropyl-4-oxo-4H-quinolizine-3-carboxylic acid (210 mg, 524.49 μmol) in pyridine (2.5 g, 31.5 mmol) was added Br2 (210 mg, 1.3 mmol). The resulting mixture was stirred at 100 °C for 2 hours. The reaction mixture was concentrated under reduced pressure. The crude was purified by prep-TLC (SiO2, DCM/MeOH = 10/1) to give the title compound (110 mg, 45% yield) as a yellow solid. MS (ESI): mass calcd. for C18H20BrFN4O2, 422.1; m/z found, 425.0 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.09 (d, J = 7.8 Hz, 1H), 8.51 (d, J = 7.0 Hz, 1H), 8.02 (s, 1H), 4.07 (s, 3H), 3.60 - 3.44 (m, 1H), 3.29 (br s, 1H), 1.78 (s, 6H), 1.40 (d, J = 7.0 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ -133.76 (1F) ppm. Intermediate 9: 8-(3-((Benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-3- bromo-7-fluoro-1-isopropyl-4H-quinolizin-4-one.
Figure imgf000047_0001
Step A.3-((Benzyloxy)methyl)-1-(2-chloro-5-fluoropyridin-4-yl)-4-ethyl-1H-1,2,4-triazol- 5(4H)-one. To a mixture of 2-chloro-5-fluoro-4-iodopyridine (10 g, 38.9 mmol), 3- ((benzyloxy)methyl)-4-ethyl-1H-1,2,4-triazol-5(4H)-one (9.1 g, 38.9 mmol), (1R, 2R)-N1,N2- dimethylcyclohexane-1,2-diamine (3.3 g, 23.3 mmol), CuI (3.0 mg, 15.5 mmol) and K3PO4 (16.5 g, 77.7 mmol) in 1,4-dioxane (100 mL) was stirred at 120 °C for 16 hours under N2. The reaction mixture was diluted with H2O (200 mL), extracted with ethyl acetate (100 mL × 3). The combined organic layers was dried over Na2SO4, filtered and concentrated under reduced pressure. The crude was purified by column chromatography (SiO2, gradient elution: 0 – 20% ethyl acetate in petroleum ether) to give the title compound (5.3 g, 38% yield) as a light yellow oil. MS (ESI): mass calcd. for C17H16ClFN4O2, 362.1; m/z found, 363.0 [M+H]+.1H NMR (400 MHz, CDCl3) δ 8.37 (d, J = 2.8 Hz, 1H), 7.86 (d, J = 5.5 Hz, 1H), 7.44 - 7.30 (m, 5H), 4.61 (s, 2H), 4.51 (s, 2H), 3.85 (q, J = 7.1 Hz, 2H), 1.35 (t, J = 7.3 Hz, 3H) ppm. Step B.2-(4-(3-((Benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-5- fluoropyridin-2-yl)-3-methylbutanal. To a mixture of 3-((benzyloxy)methyl)-1-(2-chloro-5- fluoropyridin-4-yl)-4-ethyl-1H-1,2,4- triazol-5(4H)-one (5.3 g, 14.6 mmol), BINAP (910 mg, 1.5 mmol), Pd(OAc)2 (164 mg, 0.73 mmol) and Cs2CO3 (9.5 g, 29.2 mmol) in 1,4-dioxane (100 mL) was added 3-methylbutanal (6.3 g, 73.1 mmol). The resulting mixture was stirred at 90 °C for 12 hours. The reaction mixture was diluted with H2O (100 mL), extracted with ethyl acetate (100 mL × 2). The combined organic layers was dried over Na2SO4, filtered and concentrated under reduced pressure. The crude was purified by column chromatography (SiO2, gradient elution: 0 – 20% ethyl acetate in petroleum ether) to give the title compound (5.5 g, 82% yield) as a yellow oil. MS (ESI): mass calcd. for C22H25FN4O3, 412.2; m/z found, 413.1 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.85 (d, J = 3.5 Hz, 1H), 8.59 (d, J = 2.8 Hz, 1H), 7.63 (d, J = 6.0 Hz, 1H), 7.43 - 7.32 (m, 5H), 4.61 (s, 2H), 4.52 (s, 2H), 3.91 - 3.79 (m, 2H), 3.36 (dd, J = 3.4, 8.9 Hz, 1H), 2.67 - 2.52 (m, 1H), 1.40 - 1.31 (m, 3H), 1.07 (d, J = 6.8 Hz, 3H), 0.83 (d, J = 6.8 Hz, 3H) ppm. Step C. Diethyl 2-(2-(4-(3-((benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1- yl)-5-fluoropyridin-2-yl)-3-methylbutylidene)malonate. To a solution of 2-(4-(3- ((benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1 -yl)-5-fluoropyridin-2-yl)-3- methylbutanal (5.5 g, 12.0 mmol), diethyl malonate (3.8 g, 24.0 mmol), AcOH (2.3 g, 38.4 mmol) in EtOH (60 mL) was added piperidine (1.6 g, 19.2 mmol). Then the resulting mixture was stirred at 100 °C for 12 hours. The reaction mixture was diluted with H2O (60 mL), extracted with EtOAc (50 mL × 3). The combined organic layers was dried over Na2SO4, filtered and concentrated under reduced pressure. The crude was purified by column chromatography (SiO2, gradient elution: 0 – 30% ethyl acetate in petroleum ether) to give the title compound (5.1 g, 73% yield) as a yellow oil. MS (ESI): mass calcd. for C29H35FN4O6, 554.3; m/z found, 555.3 [M+H]+. Step D. Ethyl 8-(3-((benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7- fluoro-1-isopropyl-4-oxo-4H-quinolizine-3-carboxylate. To a solution of diethyl 2-(2-(4-(3- ((benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4- triazol-1-yl)-5-fluoropyridin-2-yl)-3- methylbutylidene)malonate (4.3 g, 7.8 mmol) in DMA (50 mL) was added Et3N (7.9 g, 77.5 mmol). Then the resulting mixture was stirred at 140 °C for 20 hours. The reaction mixture was diluted with ethyl acetate (150 mL), washed with H2O (40 mL × 4). The combined organic layers was dried over Na2SO4, filtered and concentrated under reduced pressure. The crude was purified by column chromatography (SiO2, gradient elution: 0 – 100% ethyl acetate in petroleum ether) to give the title compound (3.4 g, 86% yield) as yellow solid. MS (ESI): mass calcd. for C27H29FN4O5, 508.2; m/z found, 509.1 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.55 (d, J = 8.0 Hz, 1H), 8.56 (d, J = 7.0 Hz, 1H), 8.39 (s, 1H), 7.44 - 7.32 (m, 5H), 4.65 (s, 2H), 4.57 (s, 2H), 4.47 (q, J = 7.2 Hz, 2H), 3.91 (q, J = 7.1 Hz, 2H), 3.40 - 3.26 (m, 1H), 1.46 (t, J = 7.2 Hz, 3H), 1.43 - 1.36 (m, 9H) ppm. Step E.8-(3-((Benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1- isopropyl-4-oxo-4H-quinolizine-3-carboxylic acid. To a mixture of ethyl 8-(3- ((benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol- 1-yl)-7-fluoro-1-isopropyl-4- oxo-4H-quinolizine-3-carboxylate (4.2 g, 8.3 mmol) in THF (20 mL) was added LiOH.H2O (1.0 g, 24.8 mmol) in H2O (20 mL). Then the resulting mixture was stirred at room temperature for 12 hours. The reaction mixture was dropwise added 1M aq. HCl (20 mL) to pH=3. The mixture was filtered, and the filter cake was triturated with ethyl acetate/petroleum ether (v/v, 1/1, 15 mL) for 30 min, then the mixture was filtered. The filter cake was concentrated under reduced pressure to give the title compound (2.4 g, 59% yield) as yellow solid. MS (ESI): mass calcd. for C25H25FN4O5, 480.2; m/z found, 481.1 [M+H]+.1H NMR (400 MHz, DMSO-d6) δ 14.00 (br s, 1H), 9.48 (d, J = 7.8 Hz, 1H), 8.76 (d, J = 7.3 Hz, 1H), 8.28 (s, 1H), 7.42 - 7.36 (m, 4H), 7.36 - 7.29 (m, 1H), 4.64 (d, J = 6.0 Hz, 4H), 3.81 (q, J = 7.2 Hz, 2H), 3.37 (br s, 1H), 1.33 (d, J = 6.8 Hz, 6H), 1.27 (t, J = 7.3 Hz, 3H); 19F NMR (376 MHz, DMSO-d6) δ -135.13 (s, 1F) ppm. Step F.8-(3-((Benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1- isopropyl-4H-quinolizin-4-one.8-(3-((Benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4- triazol-1-yl)-7-fluoro-1-isopropyl-4-oxo-4H-quinolizine-3-carboxylic acid (125 mg, 0.26 mmol) in HCl (1M in H2O) (2.5 mL, 2.5 mmol) and 1,4-dioxane (0.5 mL) was stirred at 90 °C for 2 h. The mixture was diluted with EtOAc and water. The organics were extracted with EtOAc (3x). The combined organics were washed with brine, dried over sodium sulfate, filtered, and concentrated under reduced pressure. Used without further purification. MS (ESI): mass calcd. for C24H25FN4O3, 436.2; m/z found, 437.1 [M+H]+. Step G.8-(3-((Benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-3-bromo-7- fluoro-1-isopropyl-4H-quinolizin-4-one. To a solution of crude 8-(3-((benzyloxy)methyl)-4- ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1-isopropyl-4H-quinolizin-4-one (113 mg, 0.26 mmol) in DMF was added NBS (55 mg, 0.31 mmol). The mixture was stirred at room temperature for 1 h then concentrated. Used without further purification. MS (ESI): mass calcd. for C24H24BrFN4O3, 514.1; m/z found, 515.0 [M+H]+. Intermediate 10: 3-Bromo-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1- isopropyl-4H-quinolizin-4-one.
Figure imgf000050_0001
Step A. Ethyl 7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-4- oxo-4H-quinolizine-3-carboxylate. To a mixture of 2-(1-methyl-4-(tributylstannyl)-1H-imidazol- 2-yl)propan-2-ol (Intermediate 1, 1 g of crude in 17.5 mL toluene ) in dioxane (17.5 mL) was added ethyl 8-bromo-7-fluoro-1-isopropyl-4- oxo-4H-quinolizine-3-carboxylate (Intermediate 7, 500 mg, 1.4 mmol) and Pd(Ph3P)2Cl2 (98 mg, 139 μmol). The resulting mixture was stirred at 100 °C for 18 hours under N2. The reaction mixture was purified by column chromatography (SiO2, gradient elution: 0 – 100% ethyl acetate in petroleum ether) to give the title compound (230 mg, 37% yield) as yellow solid. MS (ESI): mass calcd. for C22H26FN3O4, 415.2; m/z found, 416.1 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.16 (d, J = 8.3 Hz, 1H), 8.37 (d, J = 7.3 Hz, 1H), 8.29 (s, 1H), 6.93 (d, J = 4.5 Hz, 1H), 4.46 (q, J = 7.2 Hz, 2H), 4.28 (s, 1H), 3.71 (s, 3H), 3.45 (m, 1H), 1.74 (s, 6H), 1.48 - 1.42 (m, 9H); 19F NMR (376 MHz, CDCl3) δ -134.86 (1F) ppm. Step B. Lithium 7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl- 4-oxo-4H-quinolizine-3-carboxylate. To a mixture of ethyl 7-fluoro-8-(2-(2-hydroxypropan-2- yl)-1-methyl-1H-imidazol-4-yl)-1-iso propyl-4-oxo-4H-quinolizine-3-carboxylate (100 mg, 205 μmol) in MeOH/THF (v/v, 1/1, 3 mL) was added LiOH.H2O (104 mg, 2.5 mmol) in H2O (1.5 mL). Then the resulting mixture was stirred at room temperature for 12 hours. The reaction mixture was concentrated under reduced pressure to give the title compound (230 mg, 205.0 μmol, 35% purity) as a yellow solid. MS (ESI): mass calcd. for C20H21FN3O4. Li, 393.2; m/z found, 388.1 [M+H]+. Step C.3-Bromo-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1- isopropyl-4H-quinolizin-4-one. The mixture of lithium 7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1- methyl-1H-imidazol-4-yl) -1-isopropyl-4-oxo-4H-quinolizine-3-carboxylate (200 mg, 178 μmol) in pyridine (1.5 g, 17.8 mmol) was added Br2 (85 mg, 534 μmol). The resulting mixture was stirred at 100 °C for 2 hours. The crude was purified by prep-TLC (SiO2, DCM/MeOH = 10/1) to give the title compound (60 mg, 69% yield, 87% purity) as a red solid. MS (ESI): mass calcd. for C19H21BrFN3O2, 421.1; m/z found, 424.0 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.02 (d, J = 8.3 Hz, 1H), 8.37 (d, J = 7.5 Hz, 1H), 7.93 (s, 1H), 6.99 (d, J = 4.3 Hz, 1H), 4.09 (br s, 1H), 3.79 (s, 3H), 3.51 (m, 1H), 1.75 (s, 6H), 1.40 (d, J = 6.8 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ -135.54 (1F) ppm. Example 1: 7-Fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-3- (o-tolyl)-4H-quinolizin-4-one.
Figure imgf000051_0001
To a mixture of 3-bromo-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl) -1- isopropyl-4H-quinolizin-4-one (Intermediate 10, 60 mg, 123 μmol), o-tolylboronic acid (25.1 mg, 184 μmol), Pd(dppf)Cl2 (13.5 mg, 18.5 μmol) and Cs2CO3 (73.5 mg, 225.5 μmol) in dioxane/H2O (v/v, 5/1, 2.5 mL) was stirred at 100 °C for 3 hours under N2. The reaction mixture was purified by prep-TLC (SiO2, DCM/MeOH = 10/1) to give a crude product (60 mg, 122.08 μmol) as yellow solid. The yellow solid was purified by preparative reversed phase HPLC (Stationary phase: Boston Prime C18, 5μm, 150 × 30 mm ; Mobile phase: water (0.05% NH3H2O + 10 mM NH4HCO3) (A) - MeCN (B), gradient elution: 47 - 77% B in A over 8 min, flow rate: 30 mL/min) to give the title compound (27 mg, 49% yield) as a yellow solid. MS (ESI): mass calcd. for C26H28FN3O2, 433.2; m/z found, 434.3 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.26 (d, J = 8.3 Hz, 1H), 8.50 (br d, J = 7.3 Hz, 1H), 7.65 (s, 1H), 7.45 (d, J = 4.3 Hz, 1H), 7.37 - 7.27 (m, 4H), 3.91 (s, 3H), 3.65 - 3.47 (m, 1H), 3.17 (br s, 1H), 2.29 (s, 3H), 1.76 (s, 6H), 1.37 (d, J = 6.8 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ -138.23 (1F) ppm. Example 2: 7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl- 3-(o-tolyl)-4H-quinolizin-4-one.
Figure imgf000052_0001
The title compound was prepared in an analogous manner to Example 1 except using 3-bromo-7- fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin- 4-one (Intermediate 8) instead of 3-bromo-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H- imidazol-4-yl) -1-isopropyl-4H-quinolizin-4-one (Intermediate 10) and o-tolylboronic acid. MS (ESI): mass calcd. for C25H27FN4O2, 434.2; m/z found, 435.3 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.27 (d, J = 7.8 Hz, 1H), 8.55 (d, J = 7.3 Hz, 1H), 7.70 (s, 1H), 7.36 - 7.28 (m, 4H), 4.17 (s, 3H), 3.64 - 3.39 (m, 1H), 2.61 (br s, 1H), 2.29 (s, 3H), 1.79 (s, 6H), 1.38 (d, J = 6.8 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ -136.64 (1F) ppm. Example 3: 8-(4-Ethyl-3-(hydroxymethyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1- isopropyl-3-(o-tolyl)-4H-quinolizin-4-one.
Figure imgf000052_0002
Step A.8-(3-((Benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1- isopropyl-3-(o-tolyl)-4H-quinolizin-4-one.8-(3-((benzyloxy)methyl)-4-ethyl-5-oxo-4,5-dihydro- 1H-1,2,4-triazol-1-yl)-3-bromo-7-fluoro-1-isopropyl-4H-quinolizin-4-one (Intermediate 9, 133 mg, 0.26 mmol), 2-methylphenylboronic acid (70 mg, 0.52 mmol), XPhos Pd G3 (22 mg, 0.026 mmol), Cs2CO3 (252 mg, 0.77 mmol) in 1,4-dioxane (1.8 mL) and water (0.5 mL) was purged with Ar then heated to 100 °C for 1 h. The mixture was concentrated and purified by flash column chromatography (SiO2, 50-60% EtOAc/heptane) to provide the title compound as a bright yellow semi-solid (90 mg, 66% yield over 3 steps). MS (ESI): mass calcd. for C31H31FN4O3, 526.2; m/z found, 527.3 [M+H]+. Step B.8-(4-Ethyl-3-(hydroxymethyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1- isopropyl-3-(o-tolyl)-4H-quinolizin-4-one. To a solution of 8-(3-((benzyloxy)methyl)-4-ethyl-5- oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1-isopropyl-3-(o-tolyl)-4H-quinolizin-4-one (89 mg, 0.17 mmol) in DCM (3.0 mL) at -78 °C was added BCl3 (0.68 mL, 1 M in DCM, 0.68 mmol). The mixture was stirred for 0.5 h then quenched with MeOH followed by water. The organics were extracted with DCM, dried over sodium sulfate, filtered and concentrated. Purification by column chromatography (SiO2, 30-70% EtOAc/heptane) provided the title compound as a bright yellow solid. MS (ESI): mass calcd. for C24H25FN4O3, 436.2; m/z found, 437.3 [M+H]+.1H NMR (400 MHz, CDCl3) δ = 9.33 (d, J = 8.3 Hz, 1H), 8.36 (d, J = 7.8 Hz, 1H), 7.68 (s, 1H), 7.38 - 7.27 (m, 4H), 4.67 (d, J = 6.4 Hz, 2H), 3.94 (q, J = 7.2 Hz, 2H), 3.38 (m, 1H), 2.53 (t, J = 6.4 Hz, 1H), 2.26 (s, 3H), 1.43 (t, J = 7.1 Hz, 3H), 1.34 (d, J = 6.8 Hz, 6H). Example 4: 3-(5-Chloro-3-methyl-1H-pyrazol-4-yl)-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1- methyl-1H-imidazol-4-yl)-1-isopropyl-4H-quinolizin-4-one.
Figure imgf000053_0001
To a solution of CS2CO3 (168 mg, 514 μmol) in dioxane/H2O (v/v, 5/1, 4 mL) was added 5- chloro-3-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (Intermediate 5, 56 mg, 228 μmol), the mixture was stirred at room temperature for 2 min. Then the reagents of 3-bromo-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1 -isopropyl-4H- quinolizin-4-one (Intermediate 10, 50 mg, 114.30 μmol) and Pd(dppf)Cl2 (16.7 mg, 22.8 μmol) was added. The resulting mixture was stirred at 100 °C for 3 hours under N2. The reaction mixture was purified by prep-TLC (SiO2, DCM/MeOH = 10/1) to give a crude product (40 mg, 71.0 μmol) as a yellow solid. The yellow solid was purified by preparative reversed phase HPLC (Stationary phase: Boston Prime C18, 5μm, 150 × 30 mm; Mobile phase: water (0.05% NH3H2O + 10 mM NH4HCO3) (A) - MeCN (B), gradient elution: 27 - 57% B in A over 8 min, flow rate: 30 mL/min) to give the title compound (12.5 mg, 24% yield) as a yellow solid. MS (ESI): mass calcd. for C23H25ClFN5O2, 457.2; m/z found, 458.2 [M+H]+.1H NMR (400 MHz, CDCl3) δ 12.87 (s, 1H), 9.13 (d, J = 8.3 Hz, 1H), 8.40 (d, J = 7.8 Hz, 1H), 7.80 (d, J = 4.3 Hz, 1H), 7.72 (s, 1H), 5.48 (s, 1H), 3.92 (s, 3H), 2.21 (s, 3H), 1.61 (s, 6H), 1.32 (d, J = 6.8 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ -137.30 (1F) ppm. Example 5: 3-(5-Chloro-3-methyl-1H-pyrazol-4-yl)-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1- methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one.
Figure imgf000054_0001
Prepared in an analogous manner to Example 1 except using 3-bromo-7-fluoro-8-(5-(2- hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one (Intermediate 8) instead of 3-bromo-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H- imidazol-4-yl) -1-isopropyl-4H-quinolizin-4-one (Intermediate 10) and 5-chloro-3-methyl- 4- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (Intermediate 5) instead of o- tolylboronic acid. MS (ESI): mass calcd. for C22H24ClFN6O2, 458.2; m/z found, 459.0 [M+H]+. 1H NMR (400 MHz, CDCl3) δ 9.21 (d, J = 7.8 Hz, 1H), 8.57 (d, J = 7.3 Hz, 1H), 7.88 (s, 1H), 4.12 (s, 3H), 3.63 - 3.52 (m, 1H), 2.36 (s, 3H), 1.79 (s, 6H), 1.41 (d, J = 7.0 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ -135.66 (1F) ppm. Example 6: 7-Fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-3- (3-methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)-4H-quinolizin-4-one.
Figure imgf000055_0001
Prepared in an analogous manner to Example 4 except using 3-bromo-7-fluoro-8-(2-(2- hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl) -1-isopropyl-4H-quinolizin-4-one (Intermediate 10) and 3-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5- (trifluoromethyl)-1H -pyrazole (Intermediate 4) instead of 5-chloro-3-methyl-4-(4,4,5,5- tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (Intermediate 5). MS (ESI): mass calcd. for C24H25F4N5O2 , 491.2; m/z found, 492.2 [M+H]+.1H NMR (400 MHz, DMSO-d6) δ 13.53 - 13.35 (m, 1H), 9.13 (d, J = 8.0 Hz, 1H), 8.44 - 8.37 (m, 1H), 7.81 (d, J = 4.8 Hz, 1H), 7.65 (s, 1H), 5.49 (s, 1H), 3.92 (s, 3H), 3.63 - 3.46 (m, 1H), 2.18 (s, 3H), 1.61 (s, 6H), 1.29 (d, J = 6.8 Hz, 6H); 19F NMR (376 MHz, DMSO-d6) δ -58.44 (1F), -137.11 (1F) ppm. Example 7: 7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl- 3-(3-methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)-4H-quinolizin-4-one.
Figure imgf000055_0002
Prepared in an analogous manner to Example 4 except using 3-methyl-4-(4,4,5,5-tetramethyl- 1,3,2-dioxaborolan-2-yl)-5-(trifluoromethyl) -1H-pyrazole (Intermediate 8) instead of 3-bromo- 7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl) -1-isopropyl-4H-quinolizin- 4-one (Intermediate 10) and 3-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5- (trifluoromethyl)-1H -pyrazole (Intermediate 4) instead of 5-chloro-3-methyl-4-(4,4,5,5- tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (Intermediate 5). MS (ESI): mass calcd. for C23H24F4N6O2, 492.2; m/z found, 493.2 [M+H]+.1H NMR (400 MHz, DMSO-d6) δ 9.12 (d, J = 7.8 Hz, 1H), 8.49 (d, J = 7.3 Hz, 1H), 7.75 (s, 1H), 6.18 - 5.36 (m, 1H), 4.14 (s, 3H), 3.51 - 3.43 (m, 1H), 2.19 (s, 3H), 1.62 (s, 6H), 1.29 (d, J = 6.8 Hz, 6H); 19F NMR (376 MHz, DMSO-d6) δ - 58.42 (1F), -135.89 (1F) ppm. Example 8: 3-(2-Chloro-4-methylpyridin-3-yl)-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl- 1H-imidazol-4-yl)-1-isopropyl-4H-quinolizin-4-one.
Figure imgf000056_0001
To a mixture of 3-bromo-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl) -1- isopropyl-4H-quinolizin-4-one (Intermediate 10, 50 mg, 114 μmol), 2-chloro-4-methyl-3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (Intermediate 6, 58 mg, 229 μmol), Pd- 118 (15 mg, 22.9 μmol) and Cs2CO3 (112 mg, 343 μmol) in 1,4-dioxane/H2O (v/v, 5/1, 5.0 mL) was stirred at 60 °C for 16 hours under N2. The reaction mixture was purified by prep-TLC (SiO2, DCM/MeOH = 10/1) to give a crude product (30 mg, 53.5 μmol). The yellow solid was purified by preparative reversed phase HPLC (Stationary phase: Boston Prime C18, 5μm, 150 × 30 mm; Mobile phase: water (0.05% NH3H2O + 10 mM NH4HCO3) (A) - MeCN (B), gradient elution: 35 - 63% B in A over 8 min, flow rate: 30 mL/min) to give the title compound (14.1 mg, 26% yield) as a yellow solid. MS (ESI): mass calcd. for C25H26ClFN4O2, 468.2; m/z found, 469.2 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.30 (d, J = 8.3 Hz, 1H), 8.55 (d, J = 7.5 Hz, 1H), 8.27 (d, J = 5.0 Hz, 1H), 7.61 (s, 1H), 7.52 (d, J = 4.5 Hz, 1H), 7.19 (d, J = 5.0 Hz, 1H), 3.94 (s, 3H), 3.65 - 3.50 (m, 1H), 3.02 (s, 1H), 2.25 (s, 3H), 1.77 (s, 6H), 1.38 (dd, J = 6.8, 11.3 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ -137.36 (1F) ppm. Example 9: 3-(2-Chloro-4-methylpyridin-3-yl)-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl- 1H-1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one.
Figure imgf000057_0001
Prepared in an analogous manner to Example 8 except using 3-bromo-7-fluoro-8-(5-(2- hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3- yl)-1-isopropyl-4H-quinolizin-4-one (Intermediate 8) instead of 3-bromo-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H- imidazol-4-yl) -1-isopropyl-4H-quinolizin-4-one (Intermediate 10) and 2-chloro-4-methyl-3- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (Intermediate 6). MS (ESI): mass calcd. for C24H25ClFN5O2, 469.2; m/z found, 470.2 [M+H]+.1H NMR (400 MHz, CDCl3) δ 9.32 (d, J = 7.5 Hz, 1H), 8.61 (d, J = 7.0 Hz, 1H), 8.29 (d, J = 5.0 Hz, 1H), 7.68 (s, 1H), 7.20 (d, J = 5.0 Hz, 1H), 4.21 (s, 3H), 3.57 (quin, J = 6.9 Hz, 1H), 2.44 (s, 1H), 2.25 (s, 3H), 1.81 (s, 6H), 1.39 (dd, J = 6.8, 12.0 Hz, 6H); 19F NMR (376 MHz, CDCl3) δ -135.69 (1F) ppm.
Biological Data DHODH inhibitory activities of the compounds of Examples 1-9 were assessed using the following assays. The half maximal inhibitory concentration values (IC50) are summarized in Table 3. Biological Assays In vitro Assay: DHODH enzymatic assay To detect DHODH enzyme activities, dichloroindophenol (DCIP) is added as the final electron acceptor in the assay. DCIP can accept electrons from the reduced coenzyme Q generated in the assay, or from dihydroorotate (DHO) via FMN by binding presumably to the ubiquinone pocket. DCIP solutions are blue, with an intense absorbance around 600 nm, but becomes colorless upon reduction (J. Biol. Chem. (1986) 261, 11386). The assay buffer contained 50 nM HEPES, pH 7.5, 150 mM NaCl, 0.5 mM EDTA, and 0.1% Triton X-100 in MilliQ water. Substrate consisting of 20 mM DHO, 5mM CoQ6, and 1mM DCIP in assay buffer, initiates the reaction. The assay is run in end-point mode by quenching the reaction with the potent DHODH inhibitor brequinar. Absorbance measurements were obtained using the BMG Phera Star plate-reading spectrophotomer. Purified human DHODH was purchased from Proteros (cat. No. PR-0044). Chemicals were purchased from Sigma-Aldrich, Teknova, and Avanti Polar Lipids. Liquid handling was performed using Labcyte Echo and Formulatrix Tempest. In vitro Assay: MOLM-13 Cellular Assay MOLM-13 cells (human acute myeloid leukemia cells) were obtained from DSMZ and were maintained in RPMI 1640 + Glutamax + 25mM HEPES (Invitrogen, catalog number 72400) supplemented with 10% heat inactivated fetal bovine serum (FBS; Invitrogen, catalog number 16140). The day prior to assay set-up, cells were pelleted, resuspended in fresh media, counted, and cells were plated at 0.4 x 106 cell/mL in a T150 flask. On the day of the assay, cells were pelleted, resuspend in fresh media, counted and seeded at 5,000 cells/well in white opaque 96- well tissue culture treated microplates (Perkin Elmer, catalog number 6005680). Cells were exposed to different concentrations of test compounds at 37 ºC, 5% CO2 for 72 hours immediately after seeding. Cell viability was acquired on a Perkin Elmer Envision 2104 multilabel reader using the CellTiter-Glo assay (Promega) according to the manufacturer’s instructions. Table 3,
Figure imgf000059_0001
NT means not tested.

Claims

CLAIMS What is claimed is: 1. A compound having the structure of Formula (I):
Figure imgf000060_0001
wherein R1 is C1-6alkyl or C1-6haloalkyl;
Figure imgf000060_0002
wherein Ra is C1-6alkyl; Rb is C1-6alkyl substituted with one OH member; R3 is H or halo;
Figure imgf000060_0003
wherein Re is selected from the group consisting of: H; halo; C1-6alkyl; C1-6alkyl substituted with one member selected from the group consisting of: OH, OCH3, and OCF3; C1-6haloalkyl; C1-6haloalkyl substituted with one member selected from the group consisting of: OH, and OCH3; and OC1-6alkyl; Rf is selected from the group consisting of: H; halo; C1-6alkyl; C1-6alkyl substituted with one member selected from the group consisting of: OH, OCH3, and OCF3; C1-6haloalkyl; C1-6haloalkyl substituted with one member selected from the group consisting of: OH, and OCH3; and OC1-6alkyl; and Rg is H or C1-6alkyl; or a pharmaceutically acceptable salt, isotope, N-oxide, solvate, or stereoisomer thereof.
2. The compound according to any of claims 1, wherein R1 is C1-4alkyl; or a pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
3. The compound according to any of claims 1, wherein R1 is CH(CH3)2; or a pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
4. The compound according to any of claims 1-3, wherein R2 is or a
Figure imgf000061_0001
pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
5. The compound according to any of claims 1-3, wherein R2 is
Figure imgf000061_0002
or a pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
6. The compound according to any of claims 1-3, wherein R2 is or a
Figure imgf000061_0003
pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
7. The compound according to any of claims 1-6, wherein R3 is F.
8. The compound according to any of claims 1-7, wherein R4 is
Figure imgf000061_0004
or a pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
9. The compound according to any of claims 1-7, R4 is or a pharmaceutically
Figure imgf000061_0005
acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
10. The compound according to any of claims 1-7, wherein R4 is
Figure imgf000062_0001
; or a pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
11. A compound selected from the group consisting of: 7-Fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-3-(o-tolyl)- 4H-quinolizin-4-one; 7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-3-(o- tolyl)-4H-quinolizin-4-one; 8-(4-Ethyl-3-(hydroxymethyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1- isopropyl-3-(o-tolyl)-4H-quinolizin-4-one; 3-(5-Chloro-3-methyl-1H-pyrazol-4-yl)-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H- imidazol-4-yl)-1-isopropyl-4H-quinolizin-4-one; 3-(5-Chloro-3-methyl-1H-pyrazol-4-yl)-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H- 1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one; 7-Fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-3-(3- methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)-4H-quinolizin-4-one; 7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-3-(3- methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)-4H-quinolizin-4-one; 3-(2-Chloro-4-methylpyridin-3-yl)-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H- imidazol-4-yl)-1-isopropyl-4H-quinolizin-4-one; and 3-(2-Chloro-4-methylpyridin-3-yl)-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H- 1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one; or a pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
12. A pharmaceutical composition comprising: (A) a compound according to any of claims 1-11, or a pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof; and (B) at least one pharmaceutically acceptable excipient.
13. A pharmaceutical composition comprising an effective amount of: 7-Fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-3-(o-tolyl)- 4H-quinolizin-4-one; 7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-3-(o- tolyl)-4H-quinolizin-4-one; 8-(4-Ethyl-3-(hydroxymethyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1- isopropyl-3-(o-tolyl)-4H-quinolizin-4-one; 3-(5-Chloro-3-methyl-1H-pyrazol-4-yl)-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H- imidazol-4-yl)-1-isopropyl-4H-quinolizin-4-one; 3-(5-Chloro-3-methyl-1H-pyrazol-4-yl)-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H- 1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one; 7-Fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-3-(3- methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)-4H-quinolizin-4-one; 7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-3-(3- methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)-4H-quinolizin-4-one; 3-(2-Chloro-4-methylpyridin-3-yl)-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H- imidazol-4-yl)-1-isopropyl-4H-quinolizin-4-one; 3-(2-Chloro-4-methylpyridin-3-yl)-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H- 1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one; or a pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof; and at least one pharmaceutically acceptable excipient.
14. A method of treating a subject suffering from or diagnosed with a disease, disorder, or medical condition comprising inhibiting or altering dihydroorotate oxygenase enzyme activity in the subject by administering to the subject an effective amount of at least one compound according to any of claims 1-11, or a pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
15. The method according to claim 14, wherein the disorder, disease or medical condition is selected from the group consisting of: inflammatory disorders and autoimmune disorders.
16. The method according to claim 14, wherein the disorder, disease or medical condition is cancer.
17. The method according to claim 14, wherein the disorder, disease or medical condition is selected from the group consisting of: lymphomas, leukemias, carcinomas, and sarcomas.
18. The method according to claim 14, wherein the disorder, disease or medical condition is selected from the group consisting of: acute lymphoblastic leukemia, acute myeloid leukemia, (acute) T-cell leukemia, acute lymphoblastic leukemia, acute lymphocytic leukemia, acute monocytic leukemia, acute promyelocytic leukemia, bisphenotypic B myelomonocytic leukemia, chronic lymphocytic leukemia, chronic myelogenous leukemia, chronic myeloid leukemia, chronic myelomonocytic leukemia, large granular lymphocytic leukemia, plasma cell leukemia, and also myelodysplastic syndrome, which can develop into an acute myeloid leukemia.
19. The method according to claim 14, wherein the disorder, disease or medical condition is acute myeloid leukemia.
20. The method according to any of claims 14-19, wherein the at least one compound is: 7-Fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-3-(o-tolyl)- 4H-quinolizin-4-one; 7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-3-(o- tolyl)-4H-quinolizin-4-one; 8-(4-Ethyl-3-(hydroxymethyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)-7-fluoro-1- isopropyl-3-(o-tolyl)-4H-quinolizin-4-one; 3-(5-Chloro-3-methyl-1H-pyrazol-4-yl)-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H- imidazol-4-yl)-1-isopropyl-4H-quinolizin-4-one; 3-(5-Chloro-3-methyl-1H-pyrazol-4-yl)-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H- 1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one; 7-Fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H-imidazol-4-yl)-1-isopropyl-3-(3- methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)-4H-quinolizin-4-one; 7-Fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H-1,2,4-triazol-3-yl)-1-isopropyl-3-(3- methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)-4H-quinolizin-4-one; 3-(2-Chloro-4-methylpyridin-3-yl)-7-fluoro-8-(2-(2-hydroxypropan-2-yl)-1-methyl-1H- imidazol-4-yl)-1-isopropyl-4H-quinolizin-4-one; 3-(2-Chloro-4-methylpyridin-3-yl)-7-fluoro-8-(5-(2-hydroxypropan-2-yl)-1-methyl-1H- 1,2,4-triazol-3-yl)-1-isopropyl-4H-quinolizin-4-one; or a pharmaceutically acceptable salt, solvate, stereoisomer, isotopic variant, or N-oxide thereof.
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