WO2015011008A1

WO2015011008A1 - 7-azaindole derivatives as parp inhibitors

Info

Publication number: WO2015011008A1
Application number: PCT/EP2014/065367
Authority: WO
Inventors: Giuseppe Giannini; Loredana Vesci; Sabrina Dallavalle; Lucio Merlini
Original assignee: Sigma-Tau Industrie Farmaceutiche Riunite S.P.A.
Priority date: 2013-07-25
Filing date: 2014-07-17
Publication date: 2015-01-29

Abstract

The present invention relates to 7-azaindole derivatives of Formula (I), pharmaceutical compositions containing such derivatives. The invention further relates to said pharmaceutical compositions for use in medicine, and more particularly in the treatment of cancer diseases where an inhibition of PARP is responsive.

Description

TITLE

7-AZAINDOLE DERIVATIVES AS PARP INHIBITORS

OF THE INVENTION

The present invention relates to 7-azaindole derivatives having antitumor properties through, as one possible biological target, poly-ADP-ribose polymerase (PARP) inhibition, and more particularly PARP-1 sub-family. The invention includes such compounds for use in medicine, in relation to cancer diseases as well as other diseases where an inhibition of PARP is responsive. The invention further relates to pharmaceutical compositions containing such compounds.

BACKGROUND OF THE INVENTION

Poly (ADP-ribose) polymerases (PARPs) are a family of proteins whose main roles involve maintaining DNA integrity and programmed cell death. So far 18 members have been recognized, but PARP-1 and PARP-2 are the two most studied isoforms. PARPs mediated DNA repair utilizes base excision repair pathway (Rouleau M., et al., Nat. Rev. Cancer 2010, 10, 293). Blocking PARP's activity prevents DNA damage repair which finally leads to cell death through induction of DNA double- strand breaks (DSBs). Lately, a new mechanism of action of PARP inhibitors has however been discovered. It has been demonstrated that when bound to some inhibitors, PARP protein instead of being released from DNA once the repair process has started, remains trapped on DNA preventing its replication and consequently cell division (Murai J., et al., Cancer Res., 72, 2012, 5588). PARP repair process involves the binding of damaged DNA to N-terminal zinc finger motif of PARP activating its catalytic C-terminal domain to hydrolyze NAD⁺ leading to the production of linear and branched poly-ADP-ribose chains.

Besides the fact that enhanced PARP-1 expression and/or activity has been reported in different tumor cell lines such as hepatocellular carcinoma, colorectal carcinoma, cervical carcinoma, malignant lymphomas, and leukaemia; PARP is also known to have a stimulated catalytic activity in response to DNA damage (Ame J.C., et al., J. Biol. Chem., 1999, 274, 17860).

It is well-known that many anti-cancer therapies implicate DNA damage. Examples of such therapies comprise use of temozolomide (TMZ), platinum-based drugs, topoisomerase inhibitors and radiotherapy. Said therapies are however shadowed by the emergence of resistance, notably due to DNA repair through PARP pathway, undermining their efficacy. Such observation led to the development of combination therapies wherein resistance to the mechanism of action of the DNA damaging drugs was hampered by PARP inhibition.

It has even been shown that PARP inhibition could potentiate the effect of DNA damaging agents (Liu X., et al., Mol. Cancer Res., 2008, 6, 1621; WQsierska-G¾dek, J., et al., Biochem. Pharmacol., 2012, 84, 1318) as well as radiotherapy.

It has been shown that cancer cells presenting at least one of BRCAl and BRCA2 mutated tumor suppressor gene are very sensitive to PARP1 inhibition, resulting in cell cycle arrest and apoptosis. This suggests a role for PARP inhibitors as single agents in cancers exhibiting BRCAl and/or BRCA2 mutations (Ratnam K., et al., Clin. Cancer Res., 2007, 13, 5, 1383).

Most PARP inhibitors in advanced clinical trials either as stand-alone monotherapies or as combination therapies have a nicotinamide-based structure aimed at competing with NAD⁺ (e.g., olaparib (AZD2281), veliparib (ABT-888), niraparib (MK-4827 and BMN-673).

Rucaparib (AG-014699) CEP-9722 _BMN

Conformational^ constrained benzamide cyclic derivatives have been explored with more or less success as nicely reviewed by Costantino et al. (Costantino G., et al., J. Med. Chem., 2001, 44, 23, 3786) and more recently by Papeo, G., et al. (Papeo, G., et al, Expert Opin. Ther. Patents, 2013, 23, 503).

Even more constrained tricyclic derivatives (i.e., a pyrrolo-tetrahydro- benzazepinone) are currently in clinical trial. Indeed, rucaparib is being assessed, in phase II, in advanced BRCAl and BRCA2 mutated ovarian and/or locally advanced or metastatic breast cancer (Drew Y., et al, J. Clin. Oncol. 2011, 29, 3104) as monotherapy. Rucaparib has also been tested in combination on 39 ovarian cell lines with other chemotherapeutic agents showing synergism with topotecan; synergism, or additive effects with carboplatin, doxorubicin and paclitaxel; and additive effects only with gemcitabine (Ihnen M., et al., Mol. Cancer Ther., 2013, 12, 1002).

PARP inhibitors have been, or are still involved in clinical trials. 92 of them can be retrieved from the National Institutes of Health website (www.clinicaltrials.gov). However, until now, no PARP inhibitor has yet been approved for the treatment of cancer. Therefore there is an urgent need to devise potent PARP inhibitors to offer adequate treatment to people in need thereof.

It has now been surprisingly found that a novel class of 7-azaindole derivatives presents strong inhibitory property against PARP enzyme.

Almost 50 years ago, the synthesis of 7-azaindole derivatives was reported hypothesizing a potential role of these adducts as purine antimetabolites; however without presenting any biological data to corroborate the assertion (Kelly A.H., et al, Can. J. Chem., 1966, 44, 2455).

Some other 7-azaindole derivatives are already known for their usefulness as fungicides in the field of agriculture (Ohshiro Y., et al., Science and Technology, 2000, 12, 15).

Some further 7-azaindole derivatives are also known as GnRH antagonists (Ujjainwalla F., et al, Tetrahedron Lett., 2001, 42, 6441).

Still further 4-arylamino-substituted 7-azaindoles derivatives have been reported as cytokinin analogues able to inhibit myeloblasts leukaemia HL-60 cell line proliferation. However, such inhibition is mentioned to occur at relatively high concentrations only.

Compound L-745,870, a 7-azaindole substituted in position 3 of the skeleton has been reported to possess antagonist properties against dopamine receptor D4 demonstrating antipsychotic effects in animal models (Moustgaard A., et al, Behav. Brain Fund., 2008, 4, 49), but without showing any clinical efficacy in schizophrenic patients (Patel S., et al, J. Pharmacol Exp. Ther., 1997, 283, 636). Still further 7-azaindole derivatives have been reported as c-kit kinase ligands (WO2006009755). Even in such patent application all adducts are substituted in position 3 of the skeleton.

DESCRIPTION OF THE INVENTION

The present invention relates to a new class of 7-azaindole derivatives having antitumoural properties through, as one possible biological target, poly-ADP-ribose polymerase (PARP) inhibition, and more particularly PARP-1 sub-family. The invention includes such compounds for use in medicine, in relation to cancer diseases as well as other diseases where an inhibition of PARP is responsive, and the pharmaceutical composition containing such compounds. The main characterizing portion of the instant adducts resides in azaindole substituted in position 6.

The invention provides compounds of formula (I) or a salt, N-oxide, hydrate or solvate thereof, as well as the preparation of pharmaceutical compositions for inhibition of PARP activity:

Formula I

wherein

R¹ is phenylene optionally substituted by one or more (Ci-C6)-alkoxy, halo, or amino; pyrrolyl, or is absent;

R² is the group -CO-, -CH2-, or is absent;

R³ is Ph, NR⁴R⁵ or is absent;

R⁴ and R⁵, the same or different are H or Me; or when taken together R⁴ and R⁵ represent a 5- or 6-membered heterocyclic moiety optionally containing another heteroatom selected from the group consisting of nitrogen and oxygen, said heterocyclic moiety being optionally substituted once or twice by (Ci-Ce)-alkyl or R⁶- CO-;

R⁶ is (Ci-C₆)-alkyl or (C₃-C₆)-cycloalkyl;

R⁷ is halo, or H; with the proviso that not all of R¹, R² and R³ are absent at the same time;

their tautomers, their geometrical isomers, their optically active forms such as enantiomers, diastereomers and their racemate forms, as well as their pharmaceutically acceptable salts thereof.

The term "alkyl" refers to linear or branched alkyl groups having from 1 to 20 carbon atoms, or preferably, 1 to 12 carbon atoms, or even more preferably 1 to about 6 carbon atoms.

The term "cycloalkyl" refers to a saturated monocyclic hydrocarbon group containing from 3 to 6 carbon atoms such as such as cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl.

The term "alkoxy" refers to the group -OR wherein R represents an alkyl moiety as above- defined.

The term "amino" refers to the group -NR'R", wherein R' and R" are independently H or alkyl, wherein alkyl refers to the group as above- defined.

The term "halo" refers to atoms selected from the group consisting of F, CI, Br and I. One embodiment of the present invention relates to compounds of formula I for use as medicaments.

In a further embodiment, said medicament is used for treating a subject afflicted by cancer diseases, the latter being potentially metastatic.

In a still further embodiment the preferred compounds of formula I are the ones where R¹ represents a phenylene moiety.

In an even more preferred embodiment, said compounds of formula I have a R² radical wherein R² represents CH2.

In a still further preferred embodiment said compounds of formula I are selected from the group consisting of:

6-phenylpyrrolo[2,3-b]pyridine-l-carboxamide;

6-(4-methoxyphenyl)pyrrolo[2,3-b]pyridine-l-carboxamide;

6- (4- dimethylaminophenyl)pyrrolo [2 , 3-b] pyridine- 1 - carboxamide ;

6-(4-fluorophenyl)pyrrolo[2,3-b]pyridine-l-carboxamide;

6-(4-phenylphenyl)pyrrolo[2,3-b]pyridine-l-carboxamide;

6- (1 H-pyrrol-2 -yl)pyrr olo [2 , 3-b] pyridine- 1 - carboxamide ;

6-(2-fluorophenyl)pyrrolo[2,3-b]pyridine-l-carboxamide; 6-[3-[4-(cyclopropanecarbonyl)piperazine-l-carbonyl]-4-fluoro-phenyl]pyrrolo[2,3- b]pyridine- 1-carboxamide;

6-[4-(piperidine-l-carbonyl)phenyl]pyrrolo[2,3-b]pyridine-l-carboxamide;

6-[4-(morpholinomethyl)phenyl]pyrrolo[2,3-b]pyridine-l-carboxamide;

6- [4- (1 -piperidylmethyl)phenyl]pyrrolo [2 , 3-b] pyridine- 1 - carboxamide ;

6-pyrrolidin-l-ylpyrrolo[2,3-b]pyridine-l-carboxamide;

6-(4-methylpiperazin-l-yl)pyrrolo [2, 3-b]pyridine- 1-carboxamide;

6- (1 -piperidyl)pyrrolo [2 , 3-b] pyridine- 1 - carboxamide ;

6- [4- [(4-methylpiperazin- 1 -yl)methyl] phenyl] pyrrolo [2 , 3-b] pyridine- 1-carboxamide ; 6- [4-(pyrrolidin-l-ylmethyl)phenyl]pyrrolo [2, 3-b]pyridine- 1-carboxamide;

6- [4-(dimethylaminomethyl)phenyl]pyrrolo [2, 3-b]pyri dine- 1-carboxamide; and 3-chloro-6-pyrrolidin-l-yl-pyrrolo[2,3-b]pyridine-l -carboxamide.

In a more preferred embodiment said compounds of formula I are selected from the group consisting of:

6-phenylpyrrolo [2, 3-b]pyridine- 1-carboxamide;

6- (4- dimethylaminophenyl)pyrrolo [2 , 3-b] pyridine- 1 - carboxamide ;

6- (1 H-pyrrol-2 -yl)pyrr olo [2 , 3-b] pyridine- 1 - carboxamide ;

6- [4- (1 -piperidylmethyl)phenyl]pyrrolo [2 , 3-b] pyridine- 1 - carboxamide ;

6-pyrrolidin-l-ylpyrrolo[2,3-b]pyridine-l-carboxamide;

6-(4-methylpiperazin-l-yl)pyrrolo [2, 3-b]pyridine- 1-carboxamide;

6- [4-(pyrrolidin-l-ylmethyl)phenyl]pyrrolo [2, 3-b]pyridine- 1-carboxamide; and

6- [4-(dimethylaminomethyl)phenyl]pyrrolo [2, 3-b]pyri dine- 1-carboxamide.

The invention furthermore provides a process for the preparation of compounds of formula I, which can be prepared by conventional synthetic methods and are described underneath.

Compounds of formula I, where R¹ represents phenylene can be obtained by a process comprising reacting 6-bromo-lH-pyrrolo[2,3-b]pyridine with an aryl boronic acid in the presence of l,l'-bis(diphenylphosphino)ferrocene-palladium(II)dichloride dichloromethane complex and of an inorganic base in a polar solvent at a temperature of at least 110°C.

Alternatively, compounds of formula I, where R¹ represents phenylene can be obtained by a process comprising reacting 6-bromo-iV,N-bis[(4- methoxyphenyl)methyl]pyrrolo[2,3-b]pyridine-l-carboxamide with an aryl boronic acid in the presence of l,l'-bis(diphenylphosphino)ferrocene-palladium(II)dichloride dichloromethane complex and of an inorganic base in a polar solvent at a temperature of at least 100°C.

Compounds of formula I, where R¹ and R² are absent and wherein R³ is NR⁴R⁵ with R⁴ and R⁵ taken together to represent a 5- or 6-membered heterocyclic moiety can be obtained by a process comprising reacting under inert atmosphere 7- hydroxy-lH-pyrrolo[2,3-b]pyridinium 3-chlorobenzoate with dimethyl sulfate in a polar aprotic solvent for around 12 h at a temperature around 60°C, prior to add a compound of Formula II

HNR⁴R⁵ Formula II

and let the reaction under stirring for around 8 h.

In all said transformations, any interfering reactive group can be protected and then deprotected according to well-established procedures described in organic chemistry (see for example: Greene T. W. and P.G.M. Wuts "Protective Groups in Organic Synthesis", J. Wiley & Sons, Inc., 3rd Ed., 1999) and well known to those skilled in the art.

All said transformations are only examples of well-established procedures described in organic chemistry (see for example: March J., "Advanced Organic Chemistry", J. Wiley & Sons, Inc., 4th Ed., 1992) and well known to those skilled in the art.

The invention furthermore provides pharmaceutical compositions comprising at least one compound of formula I as the active ingredient, together with at least one pharmaceutically acceptable vehicle and/or excipient. These may be particularly useful formulation coadjuvants, e.g. solubilizing agents, dispersing agents, suspension agents, and emulsifying agents.

The compositions covered by the present invention are entirely conventional and are obtained with methods which are common practice in the pharmaceutical industry, such as, for example, those illustrated in Remington's Pharmaceutical Science Handbook, Mack Pub. N.Y. - last edition. According to the administration route chosen, the compositions will be in solid or liquid form, suitable for oral, parenteral or topical administration.

The amount of the pharmaceutical agents actually administered will typically be determined by a physician, in the light of the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compounds administered, drug combination, the age, body weight, and response of the individual patient, the severity of the patient's symptoms, and the like. For any compound, the therapeutically effective dose can be estimated initially either in cell culture assays or in animal models, usually mice, rats, guinea pigs, rabbits, dogs, or pigs. The animal model may also be used to determine the appropriate concentration range and route of administration. Such information can then be used to determine useful doses and routes for administration in humans. In calculating the Human Equivalent Dose (HED) it is recommended to use the conversion table provided in Guidance for Industry and Reviewers document (2002, U.S. Food and Drug Administration, Rockville, Maryland, USA).

Generally, an effective dose will be from 0.01 mg/kg to 2000 mg/kg of pharmaceutical agents, preferably from 0.05 mg/kg to 500 mg/kg of pharmaceutical agent. The precise effective dose for a human subject will depend upon the severity of the disease state, general health of the subject, age, weight, and gender of the subject, diet, time and frequency of administration, drug combination(s), reaction sensitivities, and tolerance/response to therapy. This amount can be determined by routine experimentation and is within the judgment of the clinician.

The compositions in question may, together with the compounds of Formula (I), contain further known active principles.

Thus, another embodiment of the present invention relates to combination compositions wherein the further known active principle is a DNA damaging agent. In an even more preferred embodiment of the present invention the DNA damaging agent is temozolomide.

The medicament of this invention may be administered by any number of routes including, but not limited to, oral, intravenous, intramuscular, intra- arterial, intramedullary, intrathecal, transdermal or transcutaneous applications, intraperitoneal, intranasal, enteral, or topical means.

The compositions for oral administration may take the form of bulk liquid solutions or suspensions, or bulk powders. More commonly, however, the compositions are presented in unit dosage forms to facilitate accurate dosing. The term "unit dosage forms" refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient.

The medicament may also contain a pharmaceutically acceptable carrier, for administration of a therapeutic agent. Such carriers include antibodies and other polypeptides, genes and other therapeutic agents such as liposomes, provided that the carrier does not induce the production of antibodies harmful to the individual receiving the composition, and which may be administered without undue toxicity. Suitable carriers may be large, slowly metabolized macromolecules such as proteins, polysaccharides, polylactic acids, polyglycolic acids, polymeric amino acids, amino acid copolymers and inactive virus particles. A thorough discussion of pharmaceutically acceptable carriers is available in Remington's Pharmaceutical Sciences (Mack Pub. Co., N.J. 1991).

Pharmaceutically acceptable carriers in therapeutic compositions may additionally contain liquids such as water, saline, glycerol and ethanol.

Additionally, auxiliary substances, such as wetting or emulsifying agents, pH buffering substances, and the like, may be present in such compositions. Such carriers enable the pharmaceutical compositions to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions, and the like, for ingestion by the patient.

The term "therapeutically effective dose" refers specifically to the cumulative dose of the combination involving pharmaceutical agent (a) and (b).

A further object of the invention is a process for the preparation of pharmaceutical compositions characterized by mixing at least one pharmaceutical agent (a) and a pharmaceutical agent (b) with suitable excipients, stabilizers and/or pharmaceutically acceptable diluents.

According to another embodiment of the present invention the cancer to be treated is a primary tumor, selected from the group comprising sarcoma, carcinoma, melanoma, bone tumor, neuroendocrine tumor, lymphoid leukaemia, myeloid leukaemia, monocytic leukaemia, megakaryocytic leukaemia, acute promyelocytic leukaemia or Hodgkin's disease.

The above mentioned sarcoma and carcinoma consist of the group comprising: breast cancer; lung cancer, including non-small cell lung cancer (NSCLC) and small-cell lung cancer (SCLC); gastrointestinal cancer, including oesophageal, gastric, small bowel, large bowel, rectal and colon cancer; glioma, including glioblastoma; ovarian cancer; cervical cancer; endometrial cancer; mesothelioma; renal cancer; prostate cancer; peritoneum cancer; pleura cancer; face and neck cancer; bladder cancer; brain cancer; and cancer of the skin or the eyes.

The neoplasm can also refer to a paediatric cancer. For example paediatric cancers that can be treated or where the progression of the condition can be delayed according to the present invention are selected from the group consisting of: acute lymphoblastic leukaemia, acute myeloid leukaemia, adrenocortical carcinoma, astrocytomas, bladder cancer, brain stem glioma, central nervous system atypical teratoid/rhabdoid cancer, brain cancer, central nervous system embryonal cancers, brain cancer, astrocytomas, craniopharyngioma, ependymoblastoma, ependymoma, childhood medulloblastoma, medulloepithelioma, pineal parenchymal cancers of intermediate differentiation, supratentorial primitive neuroectodermal cancers and pineoblastoma, breast cancer, bronchial cancers, carcinoid cancer, cervical cancer, chordoma, colorectal cancer, oesophageal cancer, extra cranial germ cell cancer, gastric cancer, glioma, hepatocellular (liver) cancer, Hodgkin lymphoma, kidney cancer, laryngeal cancer, leukaemia, acute lymphoblastic/myeloid leukaemia, liver cancer, non-Hodgkin lymphoma, medulloblastoma, mesothelioma, multiple endocrine neoplasia syndrome, nasopharyngeal cancer, oral cancer, ovarian cancer, pancreatic cancer, papillomatosis, renal cell cancer, rhabdomyosarcoma, salivary gland cancer, sarcoma, skin cancer, thymoma and thymic carcinoma, thyroid cancer and vaginal cancer.

EXAMPLES

Abbreviations:

AcOEt: ethyl acetate

Boc: i-butoxycarbonyl

bs : broad singlet

DCM: dichloromethane

DIPEA: diisopropylethylamine

DME: 1,2-dimethoxyethane

DMF: dimethylformamide

DMSO : dimethyl sulfoxide

EDC: l-ethyl-3-(3-dimethylaminopropyl)carbodiimide Et₂0: diethyl ether

HOBt: 1-hydroxybenzotriazole

KOAc: potassium acetate

LiHMDS: lithium hexamethyldisilazide

MeCN: acetonitrile

MeOH: methanol

mp: melting point

RT: room temperature

TFA: trifluoroacetic acid

THF: tetrahydrofurane

General Remarks: Reaction courses and product mixtures were routinely monitored by thin-layer chromatography (TLC) on silica gel F254 Merck plates. All drying operations were performed over anhydrous sodium sulfate. Flash column chromatography was carried out using silica gel (Merck 230-400 mesh). Yields are given after chromatographic purification. Nuclear magnetic resonance (Ή and ¹³C NMR) spectra were gathered, with a Bruker-300 MHz spectrometer, and chemical shifts are given in part per million (ppm) downfield from tetramethylsilane as internal standard. The coupling constants are given in Hz.

EXAMPLE 1

6-phenylpyrrolo [2.3-bl pyridine- 1 -carboxamide

STEP A: 6-phenyl-lH-pyrrolo[2,3-b]pyridine

A degassed dimethoxyethane/water solution (3.5/1, 2.66 ml) containing 6-bromo-lH- pyrrolo[2,3-b]pyridine (131 mg, 0.66 mmol), phenyl-boronic acid (162 mg, 1.33 mmol), PdCl₂(dppf)DCM (24.3 mg, 0.033 mmol) and sodium bicarbonate (167 mg, 2 mmol) was heated to 110°C for 2 hours under a nitrogen atmosphere. The layers were then separated and the organic phase was concentrated under vacuum. The crude reaction mixture was purified by flash chromatography to give the desired 6- phenylpyrrolo [2, 3 -b] pyridine as a white solid.

Purification: Hexane/AcOEt: 9/1.

Yield: 58%.

mp: 136°C. Ή NMR (300 MHz DMSO-d^), δ: 11.70 (1H, bs), 8.09 (2H, d, J = 7.4 Hz); 8.03 (1H, d, J = 8.2 Hz); 7.65 (1H, d, J = 8.2 Hz); 7.53-7.44 (3H, m); 7.38 (1H, m); 6.47 (8H, m). STEP B: 6-phenylpyrrolo[2,3-b]pyridine-l-carboxamide

A mixture of 6-phenyl-lH-pyrrolo[2,3-b]pyridine (485 mg, 2.5 mmol), triphosgene (297 mg, 1 mmol) and DIPEA (958 μΐ, 5.5 mmol) in toluene (350 μΐ) was heated to 80°C for 1.5 h. The temperature was then allowed to cool down to RT, and a saturated solution NH3/DCM (3 ml) was added. The stirring was maintained overnight. AcOEt was then added, and the resulting organic phase was washed with HCl (0.25 M) twice, and with a saturated NaHCOe solution twice, and finally dried over sodium sulfate. Removal of the solvent under vacuum and purification by flash chromatography led to the desired (6-phenylpyrrolo[2,3-b]pyridine-l- carboxamide as a white solid.

Purification: Hexane/AcOEt: 3/1.

Yield: 46%.

mp: 205°C.

NMR (300 MHz CDCI3), δ: 9.86 (1H, bs); 8.01-7.91 (4H, m); 7.69 (1H, d, J = 8.2 Hz); 7.58-7.41 (3H, m); 6.61 (1H, d, J = 3.8 Hz); 5.63 (1H, bs).

Unless otherwise specified, examples 2 to 6 were synthesized following procedures described in example 1 using the appropriate boronic acid derivative in Step A.

EXAMPLE 2

6-(4-methoxyphenyl)pyrrolo [2,3-blpyridine-l-carboxamide

STEP A: 6-(4-methoxyphenyl)-lH-pyrrolo[2,3-b]pyridine

Purification: Hexane/AcOEt: 7/3 to get a white solid.

Yield: 85%.

mp: 185°C.

NMR (300 MHz CDCI3), δ: 10.22 (1H, bs); 8.01 (1H, d, J = 7.8 Hz); 7.99 (2H, d, J = 8. 7 Hz); 7.51 (1H, d, J = 7.8 Hz); 7.26 (1H, m); 7.06 (2H, d, J = 8.7 Hz); 6.52 (1H, m); 3.91 (3H, s).

STEP B: 6-(4-methoxyphenyl)pyrrolo[2,3-b]pyridine-l-carboxamide

This step was completed at 80°C in 2 h.

Purification: Hexane/AcOEt: 7/3 to get a white solid.

Yield: 29%.

mp: 199°C. Ή NMR (300 MHz CDC1₃), δ: 9.88 (IH, bs); 8.02-7.88 (4H, m); 7.62 (IH, d, J = 8.4 Hz); 7.04 (2H, d, J = 8.6 Hz); 6.59 (IH, d, J = 4.4 Hz); 5.58 (IH, bs); 3.90 (3H, s).

EXAMPLE 3

6-(4-dimethylaminophenyl)pyrrolor2.3-blpyridine-l-carboxamide STEP A: (N,N-dimethyl-4-(lH-pyrrolo[2,3-b]pyridin-6-yl)aniline

Purification: Hexane/AcOEt: 7/3 to get a white solid.

Yield: 64%.

mp: 198°C.

NMR (300 MHz CDCla), δ: 11.61 (IH, bs); 8.02 (IH, d, J = 8.7 Hz); 7.96 (2H, d, J = 8.4 Hz); 7.57 (IH, d, J = 8. 7 Hz); 7.41 (IH, m); 6.89 (2H, d, J = 8.4 Hz), 6.44 (IH, m); 2.98 (6H, s).

STEP B: 6-(4-dimethylaminophenyl)pyrrolo[2,3-b]pyridine-l-carboxamide

This step was completed at 80°C in 2 h.

Purification: DCM/acetone: 99/1 to get a white solid.

Yield: 46%.

mp: 222°C.

NMR (300 MHz DMSO-ds), δ: 9.26 (IH, bs); 8.10 (IH, bs); 8.08 (IH, d, J = 8.2

Hz); 7.90 (2H, d, J = 9.1 Hz); 7.85 (IH, d, J = 4.1 Hz); 7.75 (IH, d, J = 8.2 Hz); 6.82

(2H, A, J = 9.1 Hz); 6.65 (IH, d, J = 4.1 Hz); 2.76 (6H, s).

EXAMPLE 4

6-(4-fluorophenyl)pyrrolo[2,3-blpyridine-l-carboxamide

STEP A: 6-(4-fluorophenyl)-lH-pyrrolo[2,3-b]pyridine

Purification: Hexane/AcOEt: 4/1 to get a white solid.

Yield: 82%.

mp: 216°C.

Ή NMR (300 MHz CDCI3), δ: 10.63 (IH, bs); 8.08-7.94 (3H, m); 7.49 (IH, d, J = 8.2 Hz); 7.27-7.14 (3H, m); 6.52 (IH, m).

STEP B: 6-(4-fluorophenyl)pyrrolo[2,3-b]pyridine-l-carboxamide

This step was completed at 80°C in 2.5 h.

Purification: Hexane/AcOEt: 4/1 to get a white solid.

Yield: 85%.

mp: 174°C. Ή NMR (300 MHz CDC1₃), δ: 9.75 (1H, bs), 8.01 (1H, d, J = 8.1 Hz); 7.99-7.88 (3H, m); 7.61 (1H, d, J = 8.1 Hz); 7.19 (2H, t, J = 8.8 Hz); 6.59 (1H, d, J = 4.4 Hz); 5.62 (1H, bs).

EXAMPLE 5

6-(4-phenylphenyl)pyrrolo[2,3-blpyridine-l-carboxamide

STEP A: 6-(4-phenylphenyl)-lH-pyrrolo[2,3-b]pyridine

A mixture of 4-bromobiphenyl (100 mg, 0.43 mmol), bispinacolato diboron (100 mg, 0.47 mmol), PdCl₂(dppf)DCM (9.4 mg, 0.01 mmol), KOAc (126 mg, 1.29 mmol) in dioxane (2.60 ml) was heated for 5 h at 100°C under nitrogen atmosphere. The temperature was then allowed to cool down to RT, and 6-bromo-lH-pyrrolo[2,3- b]pyridine (169 mg, 0.86 mmol), PdCl₂(dppf)DCM (9.4 mg, 0.013 mmol), 2M Na₂C0₃ (0.54 ml, 1.07 mmol) were added. The mixture was then stirred at 100°C for 4 h. Standard extraction with AcOEt and subsequent washing with 0.25 M HCl and drying over Na₂S04 gave a crude reaction mixture which was purified with Hexane/AcOEt: 85/15 to get the desired adduct as a white solid.

Yield: 57%.

mp: 245°C.

Ή NMR (300 MHz CDCI3), δ: 11.72 (1H, bs); 8.19 (2H, d, J = 7.9 Hz); 8.02 (1H, d, J = 8.4 Hz); 7.84-7.60 (5H, m); 7.55-7.32 (4H, m); 6.46 (1H, m).

STEP B: 6-(4-phenylphenyl)pyrrolo[2,3-b]pyridine-l-carboxamide

This step was completed at 80°C in 3 h.

Purification: Hexane/AcOEt: 4/1 and subsequent crystallization from Et₂0 to get a white solid.

Yield: 76%.

mp: 235°C.

Ή NMR (300 MHz OMSO-de), δ: 9.16 (1H, bs); 8.26-8.12 (4H, m), 7.98-7.91 (2H, m), 7.83 (2H, d, J = 8.2 Hz); 7.75 (2H, d, J = 7.4 Hz); 7.54-7.45 (2H, m); 7.39 (1H, t, J = 7.0 Hz); 6.73 (1H, d, J = 4.0 Hz).

EXAMPLE 6

6- (lH-pyrrol-2 - vDpyrr olo [2 , 3-bl pyridine- 1 - carboxamide

STEP A: teri-butyl 2-(lH-pyrrolo[2,3-b]pyridin-6-yl)pyrrole-l-carboxylate

A mixture of 6-bromo-lH-pyrrolo[2,3-b]pyridine (200 mg, 1.01 mmol), JV-Boc- pyrrole-2-boronic acid (321 mg, 1.52 mmol), K₂C03 (279 mg, 2.02 mmol) and Pd(PPh₃)4 (58.4 mg, 0.05 mmol) in DME/H₂0 4:1 (5.5 ml) which had been previously purged with nitrogen was stirred at 100°C for 3 h in the dark. The mixture was then diluted with DCM and washed with saturated aqueous NH4CI. The aqueous phase was extracted back with DCM and the combined organic extracts were dried over Na2S04 and concentrated under reduced pressure. Purification by flash chromatography (Hexane/Et20: 3/2) afforded the desired adduct as a light yellow solid.

Yield: 84%.

mp: 136°C.

Ή NMR (300 MHz CDCI3), δ: 12.00 (1H, bs); 7.95 (1H, d, J = 8.1 Hz); 7.45 (1H, m); 7.27-7.16 (2H, m); 6.51-6.43 (2H, m); 6.33 (1H, m); 1.18 (9H, s).

STEP B: ieri-butyl 2-(l-carbamoylpyrrolo[2,3-b]pyridin-6-yl)pyrrole-l-carboxylate This step was completed at 80°C in 1 h.

Purification: DCM/acetone: 98.5/1.5 with subsequent crystallization from Et20 to get a white solid.

Yield: 74%.

mp: 186°C.

¹H NMR (300 MHz CDCI3), δ: 9.58 (1H, bs); 7.99-7.90 (2H, m); 7.38 (1H, m); 7.34 (1H, d, J = 8.1 Hz); 6.56 (1H, m); 6.43 (1H, m); 6.27 (1H, m); 5.42 (1H, bs); 1.32 (9H, s).

STEP C: 6-(lH-pyrrol-2-yl)pyrrolo[2,3-b]pyridine-l-carboxamide

Standard removal of the Boc protecting moiety was conducted refluxing tert-butyl 2- (l-carbamoylpyrrolo[2,3-b]pyridin-6-yl)pyrrole-l-carboxylate (40 mg, 0.123 mmol) in MeOH (1.5 ml) in the presence of 10 M HC1 (16 μΐ) for 5 h. After removal of MeOH under reduced pressure, the crude reaction mixture was diluted with DCM, and washed with 10% _aq.Na2C03.

Purification: DCM/acetone: 95/5 to get a sticky solid.

Yield: 59%.

Ή NMR (300 MHz DMSO-e¾, δ: 11.75 (1H, bs); 8.92 (1H, bs); 7.98 (1H, d, J = 8.2 Hz); 7.91 (1H, bs); 7.81 (1H, d, J = 3.8 Hz); 7.60 (1H, d, J = 8.2 Hz); 6.92 (1H, m); 6.79 (1H, d, J = 3.9 Hz); 6.59 (1H, m); 6.15 (1H, d, J = 4.0 Hz). EXAMPLE 7

6-(2-fluorophenyl)pyrrolo[2,3-blpyridine-l-carboxamide STEP A: 6-(2-fluorophenyl)-lH-pyrrolo[2,3-b]pyridine

This step was completed at 110°C in 1 h following the procedure described in step A of example 1.

Purification: Hexane/AcOEt: 7/3.

Yield: 78%.

mp: 155°C.

NMR (300 MHz CDCls), δ: 11.24 (1H, bs); 8.03 (1H, d, J = 8.2 Hz); 7.93 (1H, t, J = 7.5 Hz); 7.54 (1H, dd, J = 1.9; 8.1 Hz); 7.42 (1H, m); 7.37-7.15 (3H, m); 6.50 (1H, m).

STEP B: (4-nitrophenyl) 6-(2-fluorophenyl)pyrrolo[2,3-b]pyridine-l-carboxylate

A toluene solution (20 ml) of 6-(2-fluorophenyl)-lH-pyrrolo[2,3-b]pyridine (40 mg,

0.19 mmol), 4-nitrophenylchloroformate (61 mg, 0.30 mmol), and NaOH (23 mg, 0.57 mmol) was heated to 60°C for 2 h in the presence of a catalytic amount of Bu4N⁺B (2 mg) under an atmosphere of nitrogen. Standard extraction by means of AcOEt and subsequent washing of the organic phase afforded the desired adduct which was used in the next step without further purification.

STEP C: 6-(2-fluorophenyl)pyrrolo[2,3-b]pyridine-l-carboxamide

A solution of (4-nitrophenyl) 6-(2-fluorophenyl)pyrrolo[2,3-b]pyridine-l-carboxylate (47 mg, 0.12 mmol) and (NH₄)2C0₃ (19 mg, 0.19 mmol) in dry DMF (1 ml) was heated to 60°C for 1 h. After addition of water (20 ml) the mixture was extracted three times with AcOEt. The combined organic layers were finally washed with brine and dried over Na2S0₄.

Purification: Hexane/AcOEt: 4/3 to get a yellow solid.

Yield: 58%.

mp: 186°C.

¹H NMR (300 MHz CDC1₃), δ: 9.73 (1H, bs); 8.05-7.98 (2H, m); 7.84 (1H, t, J = 7.6 Hz); 7.69 (1H, d, J = 8.2 Hz); 7.42-7.16 (3H, m); 6.61 (1H, d, J = 4.0 Hz); 5.52 (1H, bs). EXAMPLE 8

6-[3-[4-(cvclopropanecarbonyl)piperazine-l-carbonyll-4-fluoro-phenyllpyrrolo[2,3-bl- pyridine-l-carboxamide

STEP A: 2-fluoro-5-(lH-pyrrolo[2,3-b]pyridin-6-yl)benzoic acid

This step was completed following procedure of example 1 - step A, in the dark at 80°C for 2 h followed by heating to 110° for further 2 h, and using 3-carboxy-4- fluorophenylboronic acid instead of phenyl-boronic acid.

Purification: the crude reaction mixture was suspended in DCM/MeOH (20/1) and refluxed for 30 min. Once cooled it was filtered to give the desired adduct as a pale yellow sticky solid.

Yield: 54%.

Ή NMR (300 MHz DMSO-de), δ: 11.78 (1H, bs); 8.67 (1H, dd, J = 2.0, 7.5 Hz); 8.33 (1H, m); 8.06 (1H, d, J = 8.2 Hz); 7.70 (1H, d, J = 8.2 Hz); 7.53 (1H, m); 7.41 (1H, m); 6.49 (1H, m).

STEP B: [4-(cyclopropanecarbonyl)piperazin-l-yl]-[2-fluoro-5-(lH-pyrrolo[2,3- b] pyridin- 6-yl)phenyl] methanone

EDC (61 mg, 0.32 mmol) and HOBt (43 mg, 0.32 mmol) were added to a 0°C solution of 2-fluoro-5-(lH-pyrrolo[2,3-b]pyridin-6-yl)benzoic acid (68 mg, 0.27 mmol) in anhydrous DMF (2 ml). The resulting solution was stirred at 0°C for 30 min before adding DIPEA (141 μΐ, 0.31 mmol) and l-(cyclopropylcarbonyl)piperazine (115 μΐ mg, 0.81 mmol). The reaction mixture was then stirred at RT for 20 h. Standard extraction with AcOEt and washing with H2O afforded the desired adduct.

Purification: DCM/MeOH: 95/5 to get a white sticky solid.

Yield: 80%.

NMR (300 MHz CDCI3), δ: 10.88 (1H, bs); 8.18-7.95 (3H, m); 7.47 (1H, d, J = 8.4 Hz); 7.34-7.18 (2H, m); 6.50 (1H, m); 3.97-3.73 (4H, m); 3.88-3.72 (2H, m); 3.54-3.34 (2H, m); 1.75 (1H, m); 1.09-0.94 (2H, m); 0.90-0.64 (2H, m).

STEP C: (4-nitrophenyl) 6-[3-[4-(cyclopropanecarbonyl)piperazine-l-carbonyl]-4- fluoro-phenyl] pyrrolo [2 , 3-b] pyridine- 1 - carboxylate

This step was performed following procedures described in step B of example 7 heating at 110°C for 3 h. STEP D: 6- [3- [4-(cyclopropanecarbonyl)piperazine-l-carbonyl]-4-fluoro-phenyl]- pyrrolo [2 , 3-b] -pyridine- 1 -carboxamide

This step was performed following procedures described in step C of example 7 heating at 60°C for 2.5 h.

Purification: Hexane/acetone: 3/2 followed by recrystallization from DCM/Et20 to get the desired adduct as a white solid.

Yield: 23%.

mp: 184°C.

Ή NMR (300 MHz DMSO-cfc), δ: 9.60 (1H, bs); 8.08-7.93 (4H, m); 7.62 (1H, d, J = 8.1 Hz); 7.26 (1H, m); 6.60 (1H, d, J = 4.0 Hz); 5.74 (1H, bs); 3.99-3.57 (6H, m); 3.53- 3.30 (2H, m), 1.92 (1H, m); 1.06-0.98 (2H, m), 0.91-0.67 (2H, m).

EXAMPLE 9

6-[4-(piperidine-l-carbonyl)phenyllpyrrolo[2,3-blpyridine-l-carboxamide

STEP A: l-piperidyl-[4-(lH-pyrrolo[2,3-b]pyridin-6-yl)phenyl]methanone

This step was performed following procedures described in step A of example 1 heating at 110°C for 1 h.

Purification: DCM/MeOH: 97/3 to get the desired adduct as a white solid.

Yield: 89%.

mp: 183°C.

Ή NMR (300 MHz CDCla), δ: 10.64 (1H, bs); 8.11-7.97 (3H, m); 7.59-7.50 (3H, m); 7.25 (1H, m); 6.50 (1H, m); 3.86-3.66 (2H, m); 3.53-3.29 (2H, m); 1.78-1.41 (6H, m). STEP B: (4-nitrophenyl) 6-[4-(piperidine-l-carbonyl)phenyl]pyrrolo[2,3-b]pyridine- 1-carboxylate

This step was performed following procedures described in step B of example 7 in DCM instead of toluene, and RT instead than at 110°C, for 4 h.

STEP C : 6- [4-(piperidine- 1 -carbonyl)phenyl] pyrrolo [2, 3-b]pyridine- 1-carboxamide This step was performed following procedures described in step C of example 7 at 40° C for 30 min.

Purification: DCM/MeOH: 98.5/1.5 to get the desired adduct as a white solid.

Yield: 72%.

mp: 179°C. Ή NMR (300 MHz CDC1₃), δ: 9.77 (1H, bs); 8.09-7.93 (4H, m); 7.68 (1H, d, J = 8.1 Hz); 7.52 (2H, d, J = 7.3 Hz); 6.60 (1H, d, J = 3.2 Hz); 5.64 (1H, bs); 3.78-3.31 (4H, m); 1.94-1.48 (6H, m).

EXAMPLE 10

6- Γ4- (morpholinomethyDphenyll pyrrolo [2 , 3-bl pyridine- 1 -carboxamide

STE P A: 4- [ [4- (1 H-pyrrolo [2 , 3-b] pyridin- 6-yl)phenyl] methyl] morpholine

Purification: DCM/MeOH: 95/5 to get the desired adduct as a white solid.

Yield: 81%.

mp: 170°C.

Ή NMR (300 MHz CDCI3), δ: 10.75 (1H, bs); 8.02 (1H, d, J = 8.4 Hz); 7.98 (2H, d, J = 7. 7 Hz); 7.53 (1H, d, J = 8.4 Hz); 7.49 (2H, d, J = 7.7 Hz); 7.22 (1H, m); 6.50 (1H, m); 3.83-3.67 (4H, m); 3.61 (2H, s); 2.64-2.39 (4H, m).

STEP B: (4-nitrophenyl) 6-[4-(morpholinomethyl)phenyl]pyrrolo[2,3-b]pyridine-l- carboxylate

This step was performed following procedures described in step B of example 7 at 40°C instead than at 110°C, for 4 h.

STEP C: 6-[4-(morpholinomethyl)phenyl]pyrrolo[2,3-b]pyridine-l-carboxamide This step was performed following procedures described in step C of example 7 at 45°C for 3 h.

Purification: DCM/MeOH: 96/4 to get the desired adduct as a white solid.

Yield: 50%.

mp: 162°C.

Ή NMR (300 MHz CDCI3), δ: 9.82 (1H, bs); 8.05-7.89 (4H, m); 7.66 (1H, d, J = 7.9 Hz); 7.60-7.35 (2H, m); 6.59 (1H, d, J = 4.0 Hz); 5.60 (1H, bs); 3.90-3.45 (6H, m); 2.69-2.39 (4H, m).

EXAMPLE 11

6- r4-(l-piperidylmethyl)phenyllpyrrolo[2.3-blDyridine-l-carboxamide

STEP A: 6-[4-(l-piperidylmethyl)phenyl]-lH-pyrrolo[2,3-b]pyridine

Purification: DCM/MeOH: 92/8 to get the desired adduct as a white solid.

Yield: 68%.

mp: 190°C. Ή NMR (300 MHz DMSO-d<?), δ: 11.66 (1H, bs); 8.07-7.92 (3H, m); 7.62 (1H, d, J = 8. 7 Hz); 7.46 (1H, m); 7.37 (2H, d, J = 8.2 Hz); 6.44 (1H, m); 3.45 (2H, s); 2.42-2.27 (4H, m), 1.55-1.31 (6H, m).

STEP B: 6-[4-(l-piperidylmethyl)phenyl]pyrrolo[2,3-b]pyridine-l-carboxamide A solution of LiHMDS in THF (0.28 ml, 1.0 M, 0.28 mmol) was added to a solution of 6-[4-(l-piperidylmethyl)phenyl]-lH-pyrrolo[2,3-b]pyridine (75 mg, 0.26 mmol) in THF (3 ml) at -78°C. The reaction was stirred at this temperature for 40 min, whereupon 4-nitrophenyl chloroformate (104 mg, 0.51 mmol) was added portionwise over 5 min. Stirring was maintained meanwhile allowing the reaction to return to RT. Saturated aqNH/tCl (2 ml) was added and the mixture was extracted with DCM (3 x 20 ml). The combined organic layers were dried over Na2S04 and the solvent removed under reduced pressure.

Purification: DCM/MeOH: 95/5 to get the desired adduct as a white solid.

Yield: 17%.

mp: 178°C.

NMR (300 MHz CDCI3), δ: 9.82 (1H, bs); 8.03-7.94 (2H, m); 7.90 (2H, d, J = 7.8 Hz); 7.64 (1H, d, J = 8.2 Hz); 7.47 (2H, d, J = 7.8 Hz); 6.58 (1H, d, J = 4.0 Hz); 5.59 (1H, bs); 3.59 (2H, s); 2.58-2.38 (4H, m); 1.75-1.54 (4H, m); 1.50-1.39).

EXAMPLE 12

6-pyrrolidin- 1 - ylpyrrolo [2 , 3-bl pyridine- 1 -carboxamide

STEP A: 6-pyrrolidin-l-yl-lH-pyrrolo[2,3-b]pyridine

A mixture of 7-hydroxy-lH-pyrrolo[2,3-b]pyridinium 3-chlorobenzoate (1.5 g, 5.15 mmol) and dimethyl sulphate (713 mg, 5.65 mmol) was stirred for 12 h in anhydrous MeCN (10 ml) under nitrogen atmosphere at 60°C. Then pyrrolidine (2.11 ml, 25.5 mmol) was added and the resulting mixture was stirred at 55°C for 8 h under nitrogen atmosphere. The reaction mixture was then diluted by means of DCM and Na2C03 (10% in H2O). The aqueous phase was extracted back with DCM. The combined organic layers were washed with Na2C03 (10% in H2O), H2O and brine and then dried over Na2S04. Solvent was finally removed under reduced pressure.

Purification: Hexane/AcOEt: 7/3 to get a white solid.

Yield: 56%.

mp: 218°C. Ή NMR (300 MHz DMSO-d^), δ: 10.98 (1H, bs); 7.63 (1H, d, J = 8.4 Hz); 6.91 (1H, m); 6.23 (1H, d, J = 8.4 Hz), 6.17 (1H, m); 3.35-3.28 (4H, m); 1.99-1.84 (4H, m).

STEP B: 6-pyrrolidin-l-ylpyrrolo[2,3-b]pyridine-l-carboxamide

Purification: Hexane/AcOEt: 3/1 to get a white solid.

Yield: 80%.

mp: 198°C.

NMR (300 MHz DMSO-de), δ: 9.11 (1H, bs); 7.83 (1H, m); 7.77 (1H, d, J = 8.9 Hz); 7.45 (1H, d, J = 4.0 Hz); 6.43 (1H, bs); 6.41 (1H, d, J = 4.0 Hz); 3.42-3.32 (4H, m); 2.01-1.90 (4H, m).

Examples 13 and 14 have been synthesized following the procedure described at example 12.

EXAMPLE 13

6-(4-methylpiperazin-l-yl)pyrrolo[2.3-blpyridine-l-carboxamide

STEP A: 6-(4-methylpiperazin-l-yl)-lH-pyrrolo[2,3-b]pyridine

Purification: DCM/MeOH: 92/8 to get the desired adduct as a white solid.

Yield: 29%.

mp: 197°C.

Ή NMR (300 MHz DMSO-de), δ: 11.00 (1H, bs); 7.67 (1H, d, J = 8.6 Hz); 7.02 (1H, m); 6.60 (1H, d, J = 8.6 Hz); 6.19 (1H, m); 3.46-3.37 (4H, m); 2.42-2.35 (4H, m); 2.20 (3H, s).

STEP B: 6-(4-methylpiperazin-l-yl)pyrrolo[2,3-b]pyridine-l-carboxamide

This step was completed at 45°C in 1 h.

Purification: DCM/MeOH: 9/1 to get the desired adduct as a white solid.

Yield: 78%.

mp: 142°C.

Ή NMR (300 MHz CDC1₃), δ: 9.34 (1H, bs); 7.75 (1H, d, J = 8.8 Hz); 7.68 (1H, d; J = 3.8 Hz); 6.66 (1H, d, J = 8.8 Hz); 6.40 (1H, d, J = 3.8 Hz); 5.53 (1H, bs); 3.75-3.42 (4H, m); 2.91-2.60 (4H, m); 2.45 (3H, s). EXAMPLE 14

6- (1 -piperidvDpyrrolo [2 , 3-bl pyridine- 1 - carboxamide

STEP A: 6-(l-piperidyl)-lH-pyrrolo[2,3-b]pyridine

Purification: Hexane/AcOEt: 4/1 to get a white sticky solid.

Yield: 35%.

¹H NMR (300 MHz CDCla), δ: 8.72 (1H, bs); 7.73 (1H, d, J = 8.5 Hz); 6.98 (1H, m); 6.60 (1H, d, J = 8.5 Hz); 6.33 (1H, m); 3.60-3.48 (4H, m); 1.75-1.60 (6H, m).

STEP B: 6-(l-piperidyl)pyrrolo[2,3-b]pyridine-l-carboxamide

This step was completed at 40°C in 30 min.

Purification: DCM/MeOH: 8/1 to get the desired adduct as a white solid.

Yield: 62%.

mp: 148°C.

Ή NMR (300 MHz CDCI3), δ: 9.55 (1H, bs); 7.71 (1H, d, J - 8.7 Hz), 7.64 (1H, d, J = 3.8 Hz); 6.66 (1H, d, J = 8.7 Hz); 6.39 (1H, d, J = 3.8 Hz); 5.58 (1H, bs); 3.54-3.50 (4H, m); 1.80-1.60 (6H, m).

EXAMPLE 15

6- r4-[(4-methylpiperazin-l-yl^')methyllphenyllpyrrolo[2,3-blpyridine-l-carboxamide STEP A: (4-nitrophenyl) 6-bromopyrrolo[2,3-b]pyridine-l-carboxylate

This step was completed at RT in 1 h following the procedure described in step B of example 7. This intermediate was used without any further purification in the next step.

STEP B: 6-bromopyrrolo[2,3-b]pyridine-l-carboxamide

This step was completed at 50°C in 1 h following the procedure described in step C of example 7.

Yield: 100% (2 steps).

NMR (300 MHz CDCI3), δ: 9.02 (1H, bs); 7.95 (1H, d, J = 3.9 Hz); 7.81 (1H, d, J =

8.1 Hz); 7.37 (1H, d, J = 8.1 Hz); 6.59 (1H, d, J = 3.9 Hz); 5.59 (1H, bs).

STEP C: 6-[4-[(4-methylpiperazin-l-yl)methyl]phenyl]pyrrolo[2,3-b]pyridine-l- carboxamide

This step was completed at 80°C in 3.5 h following the procedure described in step A of example 1.

Purification: DCM/MeOH: 92/8 to get the desired adduct as a white solid.

Yield: 46%. mp: 151°C.

Ή NMR (300 MHz CDC1₃), δ: 9.80 (1H, bs); 8.05-7.97 (2H, m); 7.93 (2H, d, J = 8.2 Hz); 7.65 (1H, d, J = 8.1 Hz); 7.50-7.37 (2H, m); 6.60 (1H, d, J = 3.8 Hz); 5.63 (1H, bs); 3.73-3.63 (2H, m), 2.99-2.81 (6H, m); 2.70 (3H, bs).

EXAMPLE 16

6-[4-(pyrrolidin-l-ylmethyl)phenyllpyrrolo[2.3-blpyridine-l-carboxamide

This step was completed at 110°C in 1 h following the procedure described in step C of example 15 using [4-(pyrrolidin-l-ylmethyl)phenyl]boronic acid instead of phenyl-boronic acid.

Purification: DCM/MeOH: 92/8 to get the desired adduct as a white solid.

Yield: 29%.

mp: 168°C.

NMR (300 MHz CDCI3), δ: 9.73 (1H, bs); 8.04-7.94 (4H, m); 7.77 (2H, d, J = 7.3 Hz); 7.66 (1H, d, J = 8.4 Hz), 6.60 (1H, d, J = 3.4 Hz); 5.63 (lH,bs); 4.17 (2H, s); 3.39- 2.62 (4H, m); 2.33-2.12 (4H, m).

EXAMPLE 17

6- r4-(dimethylaminomethyl)phenyllpyrrolo[2.3-blpyridine-l-carboxamide

STEP A: 6-bromo-N,N-bis[(4-methoxyphenyl)methyl]pyrrolo[2,3-b]pyridine-l- carboxamide

A solution of (4-nitrophenyl) 6-bromopyrrolo[2,3-b]pyridine-l-carboxylate (138 mg, 0.38 mmol) and bis-(4-methoxybenzyl)amine (158 mg, 0.61 mmol) was heated to 60°C for 6h in dry DMF. The crude reaction product was then extracted by standard work-up with AcOEt.

Purification: Hexane/AcOEt: 4/1 to get the desired adduct as a white sticky solid. Yield: 91%.

NMR (300 MHz CDCla), δ: 7.78 (1H, d, J = 8.2 Hz); 7.50 (1H, d, J = 3.8 Hz); 7.35 (1H, d, J = 8.2 Hz); 7.32-7.15 (4H, m); 6.95-6.80 (4H, m); 6.58 (1H, d, J = 3.8 Hz); 4.55 (4H, s); 3.80 (6H, s).

STEP B: 6-[4-(dimethylaminomethyl)phenyl]-N,N-bis[(4-methoxyphenyl)methyl]- pyrrolo[2,3-b]pyridine-l-carboxamide

This step was completed at 100°C in 3 h following the procedure described in step A of example 1 using [4-(dimethylaminomethyl)phenyl]boronic acid instead of phenyl-boronic acid. Purification: DCM/MeOH: 95/5 to get the desired adduct as a white sticky solid. Yield: 57%.

NMR (300 MHz CDC1₃), δ: 8.05-7.92 (3H, m); 7.67 (1H, d, J = 8.1 Hz); 7.61 (1H, d, J = 3.7 Hz); 7.56-7.47 (2H, m); 7.41 (1H, m); 6.92-6.79 (4H, m); 6.62 (1H, d, J = 3.7 Hz); 4.61 (4H, s); 3.94 (2H, s); 3.81 (6H, s); 2.61 (6H, s).

STE P C : 6- [4- (dimethylaminomethyl)phenyl] pyrrolo [2, 3-b] pyridine- 1 - carboxamide A solution of 6-[4-(dimethylaminomethyl)phenyl]-N,N-bis[(4-methoxyphenyl)- methyl]-pyrrolo[2,3-b]pyridine-l-carboxamide (27 mg, 0.05 mmol) in TFA (2 ml) was refluxed for 10 h. TFA was then removed under. The crude reaction mixture was then diluted with DCM, washed with _aq.NaHC03, and dried over Na2S04. Removal of the solvent under vacuum led to the desired adduct.

Purification: DCM/MeOH: 17/3 to get the desired adduct as a white solid.

Yield: 78%.

mp: 199°C.

NMR (300 MHz CDCI3), δ: 9.81 (1H, bs); 8.04-7.88 (4H, m); 7.66 (1H, d, J = 8.1 Hz); 7.50 (2H, d, J - 7.9 Hz); 6.59 (1H, d, J = 3.7 Hz); 5.72 (1H, bs); 3.65 (2H, s); 2.40 (6H, s).

EXAMPLE 18

3-chloro-6-pyrrolidin-l-yl-pyrrolo[2,3-blpyridine-l -carboxamide

STEP A: 3-chloro-7-hydroxy-lH-pyrrolo[2,3-b]pyridinium 3-chlorobenzoate

MCPBA (793 mg, 4.6 mmol) was added to a solution of 3-chloro-7-azaindole (500 mg, 3.27 mmol) in DME (12 ml) and the mixture was stirred for 1 h at RT. The solvent was removed under vacuum till a white precipitate formed. The resulting suspension was cooled down to 0°C, and the solid was filtered and rinsed with cold Et20 to obtain the desired product which was used without any further purification in the next step.

STEP B: 3-chloro-6-pyrrolidin-l-yl-lH-pyrrolo[2,3-b]pyridine

This step was completed at 60°C in 15 h following the procedure described in step A of example 12.

Purification: Hexane/AcOEt: 8/2 to get a white solid.

Yield: 81%.

mp: 175°C. Ή NMR (300 MHz CDC1₃), δ: 9.17 (IH, bs); 7.70 (IH, d, J = 8.8 Hz); 6.86 (IH, s); 6.34 (IH, d, J = 8.8 Hz); 3.59-3.46 (4H, m); 2.11-1.98 (4H, m).

STEP C: (4-nitrophenyl) 3-chloro-6-pyrrolidin-l-yl-pyrrolo[2,3-b]pyridine-l- carboxylate

This step was performed following procedures described in step B of example 7 heating at 80°C for 10 h.

Purification: Hexane/AcOEt: 95/5 to get a white sticky solid.

Yield: 26%.

Ή NMR (300 MHz CDCI3), δ: 8.34 (2H, d, J = 9.1 Hz); 7.70 (IH, d, J = 8.6 Hz); 7.55 (2H, d, J = 9.1 Hz); 7.46 (IH, s); 6.61 (IH, d, J = 8.6 Hz); 3.64-3.52 (4H, m); 2.13-1.97 (4H, m).

STEP D: 3-chloro- 6-pyrrolidin- 1 -yl-pyrrolo [2, 3-b] yridine- 1 -carboxamide

This step was performed following procedures described in step C of example 7 heating at 60°C for 50 min.

Purification: Hexane/AcOEt: 4/1 to get a white solid.

Yield: 53%.

mp: 199°C.

NMR (300 MHz CDCI3), δ: 9.50 (IH, bs); 7.69 (IH, d, J = 8.6 Hz); 7.56 (IH, s); 6.43 (IH, d, J = 8.6 Hz); 5.44 (IH, bs); 3.62-3.39 (4H, m); 2.19-1.97 (4H, m).

COMPARISON EXAMPLES

EXAMPLE 19

pyrrolof2, 3- b lvyridine-1 -carboxamide

This compound was obtained at 0°C in 2 h in DCM (instead of toluene) following the procedure described in step B of example 1.

Purification: DCM/Acetone: 99/1 to get a white solid.

Yield: 20%.

mp: 169°C.

NMR (300 MHz CDCI3), δ: 9.68 (IH, bs); 8.33 (IH, dd, J = 4.9, 1.8 Hz); 8.00 (IH, d, J = 3. 7 Hz); 7.95 (IH, dd, J = 8.2, 1.8 Hz); 7.23 (IH, dd, J = 8.2, 4.9 Hz); 6.59 (IH, d, J = 3.7 Hz); 5.55 (IH, bs). EXAMPLE 20

N-carbamoylOyrrolo[2,3-blvyridine-l-carboxamide

This compound was obtained at 0°C in 2 h in DCM following the procedure described in step B of example 1.

Purification: DCM/Acetone: 99/1 to get a white solid.

Yield: 13%.

mp: 186°C.

NMR (300 MHz CDCI3), δ: 12.18 (1H, bs); 8.39 (1H, d, J = 3.8 Hz); 8.01 (1H, bs); 7.98-7.89 (2H, m); 7.25 (1H, m); 6.65 (1H, d, J = 3.8 Hz); 5.32 (1H, bs).

EXAMPLE 21

6-[4-(dimethylaminomethyl)phenyl]-N-[(4-methoxyphenyl)methyl]py

bjpyridine-l-carboxamide

This compound was obtained at RT in 4 h following the procedure described in step C of example 17.

Purification: DCM/MeOH: 95/5 to get a white solid.

Yield: 77%.

mp: 93°C.

Ή NMR (300 MHz CDCI3), δ: 8.04 (1H, d, J - 3.8 Hz); 8.00 (1H, d, J = 8.3 Hz); 7.75 (2H, d, J = 8.2 Hz); 7.64 (1H, d, J = 8.3 Hz); 7.50-7.36 (4H, m); 6.95 (2H, d, J = 8.6 Hz); 6.57 (1H, d, J = 3.8 Hz); 4.73-4.64 (2H, m); 3.85 (3H, s).

EXAMPLE 22

tert-butyl 2-(l-carbamoylpyrrolo[2,3-b]pyridin-6-yl)pyrrole-l-carboxylate

This compound corresponds to the intermediate derivative obtained from step B of example 6.

BIOLOGICAL EXPERIMENTS

EXAMPLE 23

PARP inhibition profile of the compounds of the invention was analyzed by means of Trevigen's Homogeneous PARP Inhibition Assay in 96 well plates. This assay is based on the fluorescence of resorufin, the latter being generated from the non- fluorescent precursor resazurin when PARP mediated NAD⁺ depletion is inhibited. IC50 values of representative compounds as well as of the comparison examples, calculated by means of the ALLFIT software are reported in Table 1. Table 1

IC50 < 100 nM: +++; 100 nM < IC50 < 500 nM: ++; 500 nM < IC50 < 1 μΜ: +;

IC₅o>l μΜ: NA (not active)

EXAMPLE 24

PARylation assay

HeLa cells (obtained from ATCC) were seeded in RPMI-1640 medium containing L- glutamine and further supplemented with 10% heat-inactivated foetal calf serum (FCS, Life Technologies) and 50 μg ml gentamicin. The plates were incubated for 4 to 6 h, at 37 °C, under 5% CO2 atmosphere before adding varying concentrations of compound of example 11. The plates were left incubating further 3 h in the same conditions. H2O2 (5 μΐ) was added to provoke DNA damage and after 5 min at 37°C ice-cold MeOH was added to stop the reaction. Cells were cold to -20°C and kept at this temperature for 20 min and then washed with PBS. Protein Parylation was then detected using primary PAR mAb (Alexis ALX-804-220, at the dilution 1:2000) and the secondary anti-mouse Alexa Fluor 488 antibody (Molecular probes A11029, at the dilution 1:3000). Nuclei were stained with the DNA dye Draq5 (Alexis, 5μΜ). After standing in the dark at RT for 3 h, cells were washed with PBS before detecting the fluorescence from "Operetta®" imaging system (Perkin Elmer) in order to deduce the EC50. Results are reported in Table 2. Table 2

EXAMPLE 25

Proliferation assay

The anti-proliferative activity of compound of example 11 was analyzed against the ovarian tumor cell line (wild type A2780) as well as its cellular subclone known to be resistant to doxorubicin (A2780/Dx). Tumor cells seeded in 96-well plate were grown at 10% confluency in RPMI-1640 medium containing L-glutamine and further supplemented with 10% heat-inactivated fetal calf serum (FCS, Life Technologies) and 50 μg/mL gentamicin. They were allowed to attach and recover for another 24 h. The cells were then treated with varying concentrations of compound of example 11 (or with solvent only) for 72 h. The plates were washed to remove the drug and were incubated for further 48 h. Cell viability was assessed by the sulforhodamine B (SRB) assay.

The concentration of the test compound causing a 50% inhibition of cell growth (IC50) with respect to the control was calculated from the dose/response inhibition curves and evaluated by the "Allfit" computer program. Resistance Index (RI) is expressed as the ratio between IC50 regarding the resistant cell-line and the IC50 regarding the corresponding wild type counterpart. Results are reported in Table 3.

Table 3

EXAMPLE 26

Combination with temozolomide

Compound of example 11 was tested together with temozolomide in order to assess a potential synergy between the two drugs on the proliferation of two different cell- lines (i.e., MDA-MB436 breast triple-negative carcinoma, and U87 MG glioblastoma PTEN- deficient). Cells were grown as detailed in example 25 but treated for seven days with a cocktail of drugs made of example 11 together with temozolomide, each them at various concentrations. Combination indexes are reported in Table 4.

Table 4

Claims

1. A compound having the general Formula (I)

Formula I

wherein

R² is the group -CO-, -CH2-, or is absent;

R³ is Ph, NR⁴R⁵ or is absent;

R⁶ is (Ci-C₆)-alkyl or (C₃-C₆)-cycloalkyl;

R⁷ is halo, or H;

with the proviso that not all of R¹, R² and R³ are absent at the same time;

2. The compound according to claim 1, wherein R¹ is phenylene optionally substituted by one or more alkoxy, halo, or amino.

3. The compound according to claim 2, wherein R³ is NR⁴R⁵.

4. The compound according to any one of claims 1 to 3 selected from the group consisting of:

6-phenylpyrrolo[2,3-b]pyridine-l-carboxamide;

6-(4-methoxyphenyl)pyrrolo[2,3-b]pyridine-l-carboxamide;

6- (4- dimethylaminophenyl)pyrrolo [2 , 3-b] pyridine- 1 - carboxamide ;

6-(4-fluorophenyl)pyrrolo[2,3-b]pyridine-l-carboxamide;

6-(4-phenylphenyl)pyrrolo[2,3-b]pyridine-l-carboxamide; 6- (1 H-pyrrol-2 -yl)pyrr olo [2 , 3-b] pyridine- 1 - carboxamide ;

6-(2-fluorophenyl)pyrrolo[2,3-b]pyridine-l-carboxamide;

6-[3-[4-(cyclopropanecarbonyl)piperazine-l-carbonyl]-4-fluoro-phenyl]pyrrolo[2,3- b]pyridine- 1-carboxamide;

6- [4-(piperidine-l-carbonyl)phenyl]pyrrolo [2, 3-b]pyridine- 1-carboxamide;

6-[4-(morpholinomethyl)phenyl]pyrrolo[2,3-b]pyridine-l-carboxamide;

6- [4- (1 -piperidylmethyl)phenyl]pyrrolo [2 , 3-b] pyridine- 1 - carboxamide ;

6-pyrrolidin-l-ylpyrrolo[2,3-b]pyridine-l-carboxamide;

6-(4-methylpiperazin-l-yl)pyrrolo [2, 3-b]pyridine- 1-carboxamide;

6- (1 -piperidyl)pyrrolo [2 , 3-b] pyridine- 1 - carboxamide ;

6-[4-[(4-methylpiperazin-l-yl)methyl]phenyl]pyrrolo[2,3-b]pyridine-l-carboxamide;

6- [4-(pyrroli din- l-ylmethyl)phenyl]pyrrolo [2, 3-b]pyri dine- 1-carboxamide;

6- [4-(dimethylaminomethyl)phenyl]pyrrolo [2, 3-b]pyri dine- 1-carboxamide; and

3-chloro-6-pyrrolidin-l-yl-pyrrolo[2,3-b]pyridine-l -carboxamide.

5. The compound according to claim 4 selected from the group consisting of:

6-phenylpyrrolo [2, 3-b]pyridine- 1-carboxamide;

6- (4- dimethylaminophenyl)pyrrolo [2 , 3-b] pyridine- 1 - carboxamide ;

6-(4-fluorophenyl)pyrrolo[2,3-b]pyridine- 1-carboxamide;

6- (1 H-pyrrol-2 -yl)pyrr olo [2 , 3-b] pyridine- 1 - carboxamide ;

6- [4-(l-piperidylmethyl)phenyl]pyrrolo [2, 3-b]pyridine- 1-carboxamide;

6-pyrrolidin-l-ylpyrrolo[2,3-b]pyridine-l-carboxamide;

6-(4-methylpiperazin-l-yl)pyrrolo [2, 3-b]pyridine- 1-carboxamide;

6- [4-(dimethylaminomethyl)phenyl]pyrrolo [2, 3-b]pyri dine- 1-carboxamide.

6. The compound as claimed in any one of claims 1 to 5 for use as a medicament.

7. The compound as claimed in claim 6, wherein the medicament is useful for the treatment of cancer diseases, the latter being optionally in metastatic form.

8. A pharmaceutical composition comprising at least one compound as claimed in any one of claims 1 to 5 together with a pharmaceutically acceptable excipient.

9. The pharmaceutical composition as claimed in claim 8 further comprising a chemotherapeutic agent acting as a DNA damaging agent.

10. The pharmaceutical composition as claimed in claim 9 wherein the chemotherapeutic agent acting as a DNA damaging agent is an alkylating agent.

11. Process for synthesizing compounds of claim 1 wherein R¹ represents phenylene, comprising reacting 6-bromo-lH-pyrrolo[2,3-b]pyridine with an aryl boronic acid in the presence of l,l'-bis(diphenylphosphino)ferrocene-palladium(II)dichloride dichloromethane complex and of an inorganic base in a polar solvent at a temperature of at least 110°C.

12. Process for synthesizing compounds of claim 1 wherein R¹ represents phenylene comprising reacting 6-bromo-iV,N-bis[(4-methoxyphenyl)methyl]pyrrolo[2,3- b]pyridine-l-carboxamide with an aryl boronic acid in the presence of 1,1'- bis(diphenylphosphino)ferrocene-palladium(II)dichloride dichloromethane complex and of an inorganic base in a polar solvent at a temperature of at least 100°C.

13. A process for preparing a pharmaceutical composition according to any one of claims 8 to 10 comprising mixing at least a compound according to any one of claims 1 to 5 with pharmaceutically acceptable carriers and/or excipients and/or diluent.