WO2009018344A1 - Anticancer agents - Google Patents

Abstract

The invention provides a compound of the invention, which is a compound of formula A-X-L-B, or a salt thereof, as well as compositions comprising a compound of the invention, and therapeutic methods that include the administration of a compound of the invention. The compounds of the invention are useful as therapeutic agents for the treatment of diseases such as cancer.

Description

ANTICANCER AGENTS

BACKGROUND

Nicotinamide adenine dinucleotide (NAD) plays an important role in biology and medicine. The NAD binding sites of many enzymes have sufficient variation to allow the development of agents highly selective for an enzyme of particular interest. For example, selective inhibition of NAD-dependent IMP-dehydrogenase (IMPDH) is well documented. In recent years, IMPDH emerged as an important therapeutic target for diseases that include cancer (Chen, L.et al., Curr. Med. Chem. 2008, 15, 650-670; and Pankiewicz, K. W., et al., In ASC Symposium Series; Pankiewicz, K. W., Goldstein, B. M. Eds., Oxford University Press: Washinghton, 2003). For example, numerous studies have demonstrated the importance of the IMPDH inhibitor mycophenolic acid (MPA) in cancer treatment (Gu, J. J., et al., Blood 2005, 105, 3270-3277; Olah, E., et al., Adv Enzyme Regul lOOβ, 46, 176-190; Inai, K., et al., Leuk Res 2000, 24, 761-768; and Chong, C. R., et al., J Med Chem 2006, 49, 2677-2680). Consequently, MPA has entered clinical trials in advanced multiple myeloma patients (Takebe, N., et al., Clin Cancer Res 2004, 10, 8301- 8308; and Takebe, N., et al., MoI Cancer Ther 2006, 5, 457-466). Inhibitors of IMPDH, in general, show a significant ability to trigger differentiation and/or apoptosis (Gu, J. J., et al., Blood 2005, 105, 3270-3277; Inai, K., et al., Leuk Res 2000, 24, 761-768; and Inai, K., et al., Adv Exp Med Biol 1998, 431, 549-553). Histone deacetylases (HDACs), enzymes that catalyze the removal of acetyl-groups from lysine residues of histones, represent a new class of anticancer targets (Mei, S., et al., Int J Oncol 2004, 25, 1509-1519). HDACs inhibitors alter gene transcription and exert anti-tumor effects through growth arrest, apoptosis, differentiation, and inhibition of tumor angiogenesis. Thus, differentiation triggered by HDAC inhibitors is based on a fundamentally different mechanism than that caused by inhibition of IMPDH (Kim, D. H.;et al., J Biochem MoI Biol 2003, 36, 110-119; Grunstein, M. Nature 1997, 389, 349-352; Mahlknecht, U., et al., MoI Med 2000, 6, 623-644; and Kouraklis, G., Theocharis, Oncol Rep 2006, 15, 489-494).

To date, four classes of human HDACs with 18 members have been identified. The class I, II and IV HDACs require zinc for catalytic deacetylation while class III HDACs consists of seven sirtuins which are NAD dependent and do not share homologies with the zinc dependent histone deacetylases (Mai, A., et al., J Med Chem 2005, 48, 7789-7795; Yang, T., Sauve, A. A. Aaps J 2006, 8, E632-643; and Sauve, A. A., et al., MoI Cell 2005, 17, 595-601). Chemically, the zinc dependent HDACs inhibitors can be divided into several classes such as short-chain fatty acids, benzamides, and hydroxamic acids. Three structural regions can be distinguished in these molecules; a cap (usually aromatic) region, a linker, and a metal binding group. For the metal binding group, hydroxamic acids usually exhibit higher potency then the corresponding benzamides.

A representative member of HDACs inhibitors is suberoylanilide hydroxamic acid (SAHA) which was recently approved (Vorinostat) for the treatment of cutaneous T cell lymphoma (Marks, P. A. Oncogene 2007, 26, 1351-1356).

SAHA was studied in combination with imatinib and was found to promote apoptosis in imatinib- resistant leukemic cells (Bcr/Abl positive) (see Nimmanapalli, R., et al., Blood 2003, 101, 3236- 3239; and Yu, C. R., et al., Cancer Research 2003, 63, 21 18-2126). Recently, studies showed synergism not only between imatinib and SAHA but also for combinations of new generation anti- CML drugs with SAHA (Jacquel, A., at al., Oncogene 2006; Rahmani, M., et al., MoI Pharmacol 2005, 67, 1166-1176; and Fiskus, W., et al., Clin Cancer Res 2006, 12, 5869-5878.

CML is a malignant cancer of the bone marrow that causes rapid growth of blood forming cells (myeloid precursors) in the bone marrow, peripheral blood, and body tissues. The hallmark of CML is the Philadelphia chromosome translocation, which fuses the her and c-abl genes resulting in expression of a constitutively active tyrosine kinase. There is often little hope for patients with CML upon the onset of blast crisis (BC). Currently there are only two agents that are in clinical use for CML-BC, Gleevec (imatinib, tyrosine kinase inhibitor) and tiazofurin (TR, IMPDH inhibitor). Unfortunately, patients develop resistance to both agents after several treatment cycles and therefore this condition is exceptionally difficult to repress. In spite of the success that has been reported with the agents discussed above, there remains a need for compounds and methods that are useful for treating cancers. In particular, there is a need for compounds and methods that are useful for treating cancers that are resistant to one or more of the existing therapies. SUMMARY OF THE INVENTION

A series of compounds with dual inhibitory activity (HDAC/IMPDH) have been identified. Due to a different mode of action, these compounds offer a new opportunity for the treatment of cancers, including leukemias (e.g. ) prostate, and colon cancers.

Accordingly, in one embodiment, the invention provides a compound of formula I:

A -X - L - B

wherein:

A is:

X is a direct bond, -NH-, -NH-C(=0)-, -NH-C(O)-NH-, or -NH-C(O)-C(O)-NH;

L is a saturated or unsaturated, branched or unbranched, C]-C₁₅ hydrocarbon chain that is optionally substituted on carbon with one or more oxo (=0), wherein one or more carbon atoms of the chain can optionally be replaced with O, S, NH, SO₂, a divalent aryl, or a divalent heteroaryl group;

B is:

n is 1 , 2, 3, 4, 5, or 6; or a salt thereof.

In another embodiment the invention provides a pharmaceutical composition comprising a compound of formula I, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. In another embodiment the invention provides a method for treating cancer in a patient, comprising administering an effective amount of a compound of formula I, or a pharmaceutically acceptable salt thereof, to the patient.

In another embodiment the invention provides a compound of formula I, or a pharmaceutically acceptable salt thereof, for use in medical treatment or diagnosis.

In another embodiment the invention provides the use of a compound of formula I, or a pharmaceutically acceptable salt thereof, to prepare a medicament useful for treating cancer in an animal.

In another embodiment the invention provides a compound of formula I, or a pharmaceutically acceptable salt thereof, for the prophylactic or therapeutic treatment of cancer.

In one embodiment the invention provides the use of a compound of formula I, or a pharmaceutically acceptable salt thereof, in combination with other anticancer drugs for treating malignancies.

The dual inhibitors of the invention show inhibitory activity against both IMPDH and HDACs. Both enzymes are important targets for anticancer drugs. Compound 119 described herein is one of the most potent differentiation agents ever reported.

DETAILED DESCRIPTION

As used herein, alkyl denotes both straight and branched groups; but reference to an individual radical such as propyl embraces only the straight chain radical, a branched chain isomer such as isopropyl being specifically referred to. Aryl denotes a phenyl radical or an ortho-fused bicyclic carbocyclic radical having about nine to ten ring atoms in which at least one ring is aromatic. Heteroaryl encompasses a radical of a monocyclic aromatic ring containing five or six ring atoms consisting of carbon and one to four heteroatoms each selected from the group consisting of non-peroxide oxygen, sulfur, and N(X) wherein X is absent or is H, O, (Ci-C₄)alkyl, phenyl or benzyl, as well as a radical of an ortho-fused bicyclic heterocycle of about eight to ten ring atoms derived therefrom, particularly a benz-derivative or one derived by fusing a propylene, trimethylene, or tetramethylene diradical thereto.

It will be appreciated by those skilled in the art that compounds of the invention having a chiral center may exist in and be isolated in optically active and racemic forms. Some compounds may exhibit polymorphism. It is to be understood that the present invention encompasses any racemic, optically-active, polymorphic, or stereoisomeric form, or mixtures thereof, of a compound of the invention, which possess the useful properties described herein, it being well known in the art how to prepare optically active forms (for example, by resolution of the racemic form by recrystallization techniques, by synthesis from optically-active starting materials, by chiral synthesis, or by chromatographic separation using a chiral stationary phase).

Specific values listed below for radicals, substituents, and ranges, are for illustration only; they do not exclude other defined values or other values within defined ranges for the radicals and substituents

A specific value for aryl is phenyl, indenyl, or naphthyl. A specific value for heteroaryl is furyl, imidazolyl, triazolyl, triazinyl, oxazoyl, isoxazoyl, thiazolyl, isothiazoyl, pyrazolyl, pyrrolyl, pyrazinyl, tetrazolyl, pyridyl (or its N-oxide), thienyl, pyrimidinyl (or its N-oxide), indolyl, isoquinolyl (or its N-oxide) or quinolyl (or its N-oxide).

In one embodiment of the invention, A is:

In one embodiment of the invention, X is -NH-C(=O)-, -NH-C(=0)-NH-, or -NH-C(=O)-C(=O)-NH.

In one embodiment of the invention, B is

In one embodiment of the invention, B is

In one embodiment of the invention, L is a saturated or unsaturated, branched or unbranched, Ci-Cio hydrocarbon.

In one embodiment of the invention, L is a saturated or unsaturated, branched or unbranched, Ci-C₅ hydrocarbon.

In one embodiment of the invention, L is a saturated or unsaturated, branched or unbranched, C₄-C₇ hydrocarbon.

In one embodiment of the invention, L is a saturated or unsaturated, branched or unbranched, Ci -C₃ hydrocarbon.

In one embodiment of the invention, L is,

In one embodiment of the invention, L is,

In one embodiment of the invention, the compound of formula I is selected from,

In one embodiment of the invention, the compound of formula I is:

In one embodiment of the invention, the cancer is leukemia.

In one embodiment of the invention, the cancer is chronic myelogenous leukemia.

In one embodiment of the invention, the cancer is prostate or colon cancer.

In one embodiment of the invention, the cancer is a solid cancer.

In one embodiment of the invention, the treatment destroys cancer stem cells.

In cases where compounds are sufficiently basic or acidic, a salt of a compound of formula I can be useful as an intermediate for isolating or purifying a compound of formula I. Additionally, administration of a compound of formula I as a pharmaceutically acceptable acid or base salt may be appropriate. Examples of pharmaceutically acceptable salts are organic acid addition salts formed with acids which form a physiological acceptable anion, for example, tosylate, methanesulfonate, acetate, citrate, malonate, tartrate, succinate, benzoate, ascorbate, α-ketoglutarate, and α- glycerophosphate. Suitable inorganic salts may also be formed, including hydrochloride, sulfate, nitrate, bicarbonate, and carbonate salts. Pharmaceutically acceptable salts may be obtained using standard procedures well known in the art, for example by reacting a sufficiently basic compound such as an amine with a suitable acid affording a physiologically acceptable anion. Alkali metal (for example, sodium, potassium or lithium) or alkaline earth metal (for example calcium) salts of carboxylic acids can also be made. The compounds of formula I can be formulated as pharmaceutical compositions and administered to a mammalian host, such as a human patient in a variety of forms adapted to the chosen route of administration, i.e., orally or parenterally, by intravenous, intramuscular, topical or subcutaneous routes.

Thus, the present compounds may be systemically administered, e.g., orally, in combination with a pharmaceutically acceptable vehicle such as an inert diluent or an assimilable edible carrier. They may be enclosed in hard or soft shell gelatin capsules, may be compressed into tablets, or may be incorporated directly with the food of the patient's diet. For oral therapeutic administration, the active compound may be combined with one or more excipients and used in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. Such compositions and preparations should contain at least 0.1% of active compound. The percentage of the compositions and preparations may, of course, be varied and may conveniently be between about 2 to about 60% of the weight of a given unit dosage form. The amount of active compound in such therapeutically useful compositions is such that an effective dosage level will be obtained. The 1 ablets, troches, pills, capsules, and the like may also contain the following: binders such as gum tragacanth, acacia, corn starch or gelatin; excipients such as dicalcium phosphate; a disintegrating agent such as corn starch, potato starch, alginic acid and the like; a lubricant such as magnesium stearate; and a sweetening agent such as sucrose, fructose, lactose or aspartame or a flavoring agent such as peppermint, oil of wintergreen, or cherry flavoring may be added. When the unit dosage form is a capsule, it may contain, in addition to materials of the above type, a liquid carrier, such as a vegetable oil or a polyethylene glycol. Various other materials may be present as coatings or to otherwise modify the physical form of the solid unit dosage form. For instance, tablets, pills, or capsules may be coated with gelatin, wax, shellac or sugar and the like. A syrup or elixir may contain the active compound, sucrose or fructose as a sweetening agent, methyl and propylparabens as preservatives, a dye and flavoring such as cherry or orange flavor. Of course, any material used in preparing any unit dosage form should be pharmaceutically acceptable and substantially non-toxic in the amounts employed. In addition, the active compound may be incorporated into sustained-release preparations and devices.

The active compound may also be administered intravenously or intraperitoneally by infusion or injection. Solutions of the active compound or its salts can be prepared in water, optionally mixed with a nontoxic surfactant. Dispersions can also be prepared in glycerol, liquid polyethylene glycols, triacetin, and mixtures thereof and in oils. Under ordinary conditions of storage and use, these preparations contain a preservative to prevent the growth of microorganisms.

The pharmaceutical dosage forms suitable for injection or infusion can include sterile aqueous solutions or dispersions or sterile powders comprising the active ingredient which are adapted for the extemporaneous preparation of sterile injectable or infusible solutions or dispersions, optionally encapsulated in liposomes. In all cases, the ultimate dosage form should be sterile, fluid and stable under the conditions of manufacture and storage. The liquid carrier or vehicle can be a solvent or liquid dispersion medium comprising, for example, water, ethanol, a polyol (for example, glycerol, propylene glycol, liquid polyethylene glycols, and the like), vegetable oils, nontoxic glyceryl esters, and suitable mixtures thereof. The proper fluidity can be maintained, for example, by the formation of liposomes, by the maintenance of the required particle size in the case of dispersions or by the use of surfactants. The prevention of the action of microorganisms can be brought about by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal, and the like. In many cases, it will be preferable to include isotonic agents, for example, sugars, buffers or sodium chloride. Prolonged absorption of the injectable compositions can be brought about by the use in the compositions of agents delaying absorption, for example, aluminum monostearate and gelatin.

Sterile injectable solutions are prepared by incorporating the active compound in the required amount in the appropriate solvent with various of the other ingredients enumerated above, as required, followed by filter sterilization. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and the freeze drying techniques, which yield a powder of the active ingredient plus any additional desired ingredient present in the previously sterile-filtered solutions.

For topical administration, the present compounds may be applied in pure form, i.e., when they are liquids. However, it will generally be desirable to administer them to the skin as compositions or formulations, in combination with a dermatologically acceptable carrier, which may be a solid or a liquid.

Useful solid carriers include finely divided solids such as talc, clay, microcrystalline cellulose, silica, alumina and the like. Useful liquid carriers include water, alcohols or glycols or water-alcohol/glycol blends, in which the present compounds can be dissolved or dispersed at effective levels, optionally with the aid of non-toxic surfactants. Adjuvants such as fragrances and additional antimicrobial agents can be added to optimize the properties for a given use. The resultant liquid compositions can be applied from absorbent pads, used to impregnate bandages and other dressings, or sprayed onto the affected area using pump-type or aerosol sprayers.

Thickeners such as synthetic polymers, fatty acids, fatty acid salts and esters, fatty alcohols, modified celluloses or modified mineral materials can also be employed with liquid carriers to form spreadable pastes, gels, ointments, soaps, and the like, for application directly to the skin of the user.

Examples of useful dermatological compositions which can be used to deliver the compounds of formula I to the skin are known to the art; for example, see Jacquet et al. (U.S. Pat. No. 4,608,392), Geria (U.S. Pat. No. 4,992,478), Smith et al. (U.S. Pat. No. 4,559,157) and Wortzman (U.S. Pat. No. 4,820,508).

Useful dosages of the compounds of formula I can be determined by comparing their in vitro activity, and in vivo activity in animal models. Methods for the extrapolation of effective dosages in mice, and other animals, to humans are known to the art; for example, see U.S. Pat. No. 4,938,949.

The amount of the compound, or an active salt or derivative thereof, required for use in treatment will vary not only with the particular salt selected but also with the route of administration, the nature of the condition being treated and the age and condition of the patient and will be ultimately at the discretion of the attendant physician or clinician.

The desired dose may conveniently be presented in a single dose or as divided doses administered at appropriate intervals, for example, as two, three, four or more sub-doses per day. The sub-dose itself may be further divided, e.g., into a number of discrete loosely spaced administrations; such as multiple inhalations from an insufflator or by application of a plurality of drops into the eye.

The invention will now be illustrated by the following non-limiting Examples.

Example 1 Preparation of Compound 119

Monomethyl ester 118. A solution of suberic acid monomethyl ester (116, 411 mg, 2.18 mmol), EDC (650 mg, 3.28 mmol), HOBt (295 mg, 2.18 mmol) and aniline 117 (458 mg, 2.41 mmol) in anhydrous CH₂Cl₂ (15 mL) was stirred at room temperature for 48 hours. After concentration, the residue was diluted with EtOAc (100 mL) and washed with 0.1 N HCl (50 mL), water (50 mL), sat. NaHCO₃ (50 mL) and brine (50 mL). The organic layer was dried over Na₂SO₄ and filtered. The filtrate was concentrated and the residue was purified by silica gel column chromatography (0-4% MeOHZCH₂Cl₂) to give amide 118 as a yellow solid (571 mg, 73%). ¹H NMR (CDCl₃, 600 MHz) δ 7.88 (s, IH), 7.71 (brs, 2H), 7.67 (d, J = 8.4 Hz, IH), 7.49 (s, IH), 6.91 (dd, J= 8.4, 1.8 Hz, IH), 3.96 (s, 3H), 3.67 (s, 3H), 2.38 (t, J= 7.5 Hz, 2H), 2.31 (t, J= 7.5 Hz, 2H), 1.75 (q, J= 7.2 Hz, 2H), 1.65 (q, J= 7.2 Hz, 2H), 1.44-1.30 (m, 4H). HRMS calcd for Cj₉H₂₅N₂O₅ 361.1757 (M+H)⁺, found 361.1787. Hydroxamic acid 119. To a solution of monomethyl ester 118 (253 mg, 0.70 mmol) in MeOH (6.6 niL) was added 50% aqueous hydroxylamine solution (2.2 mL) and additional MeOH (2.0 mL) was then added to clear the mixture. The reaction mixture was stirred at room temperature for 4 days, during which time hydroxylamine solution/MeOH were added to drive the reaction to complete. A solid formed was filtered, washed with MeOH/water, air-dried and dried under high vacuum to give hydroxamic acid 119 as a pale solid (167 mg, 66%). ¹H NMR (DMSO, 600 MHz) δ 10.31 (s, IH), 10.04 (s, IH), 8.64 (s, IH), 8.35 (s, IH), 7.60 (d, J= 8.4 Hz, IH), 7.55 (s, IH), 7.42 (s, IH), 7.27 (d, J= 8.4 Hz, IH), 3.89 (s, 3H), 2.30 (t, J= 7.2 Hz, 2H), 1.93 (t, J= 7.2 Hz, 2H), 1.62-1.54 (m, 2H), 1.52-1.44 (m, 2H), 1.34-1.20 (m, 4H). HRMS calcd for Ci₈H₂₄N₃O₅ 362.1710 (M+H)⁺, found 362.1725.

Example 2 Preparation of Compound 122

120 1 17

122

Monomethyl ester 121. To a solution of 3-methoxy-4-(oxazol-5-yl)aniline (117, 571 mg, 3.00 mmol) in dry CH₂Cl₂ (20 mL) at 0 ⁰C were added triphosgene (297 mg, 1.00 mmol) and then Et₃N (0.42 mL, 3.0 mmol). The resulting mixture was heated at reflux for 1.5 hours. After cooling to room temperature, additional Et₃N (1.0 mL, 7.2 mmol) and methyl 6-aminohexanoate (120, 656 mg, 3.61 mmol) were added. The resulting mixture was allowed to stir at room temperature overnight and then concentrated. The residue was dissolved in EtOAc (100 mL) and water (50 mL plus 5 mL IN HCl). After the solvent was removed, the solid precipitate was washed with water, collected and purified by silica gel column (0-4% MeOH/CH₂Cl₂) to give monomethyl ester 121 as a yellow solid (511 mg, 47%). ¹H NMR (DMSO-d₆, 600 MHz) δ 8.65 (s, IH), 8.31 (s, IH), 7.52 (d, J= 8.4 Hz, IH), 7.41 (s, IH), 7.35 (s, IH), 6.97 (d, J= 8.4 Hz, IH), 6.19 (t, J= 5.7 Hz, IH), 3.87 (s, 3H), 3.57 (s, 3H), 3.07 (dt, J= 6.3, 6.3 Hz, 2H), 2.30 (t, J= 7.2 Hz, 2H), 1.54 (tt, J= 7.5, 7.5 Hz, 2H), 1.42 (tt, J= 7.2, 7.2 Hz, 2H), 1.29 (tt, J= 7.2 Hz, 2H). HRMS calcd for C₁₈H₂₃N₃O₅Na 384.1529 (M+Na)⁺, found 384.1541.

Hydroxamic acid 122. To a suspension of monomethyl ester 121 (236 mg, 0.65 mmol) in dry MeOH (10 mL) was added hydroxylamine hydrochloride (253 mg, 3.64 mmol), followed by 25% v/v NaOMe solution (1.60 mL, 6.99 mmol). The reaction mixture was stirred at room temperature overnight and then concentrated. The residue was dissolved in water (10 mL) and acidified with IN HCl to about pH 7. The solid precipitate was filtered, washed with water and collected to give hydroxamic acid 122 as a pale solid (198 mg, 84%). ¹H NMR (DMSO-d₆, 600 MHz) δ 10.32 (brs, IH), 8.69 (s, IH), 8.65 (brs, IH), 8.31 (s, IH), 7.52 (d, J= 8.4 Hz, IH), 7.42 (s, IH), 7.35 (s, IH), 6.97 (d, J= 8.4 Hz, IH), 6.22 (brs, IH), 3.87 (s, 3H), 3.06 (dt, J= 6.0, 6.0 Hz, 2H), 1.94 (t, J= 7.2 Hz, 2H), 1.50 (tt, J= 7.2, 7.2 Hz, 2H), 1.42 (tt, J= 7.2, 7.2 Hz, 2H), 1.26 (tt, J= 7.2 Hz, 2H). HRMS calcd for C_nH₂₃N₄O₅ 363.1662 (M+H)⁺, found 363.1655.

Representative compounds of the invention 16a-19b were prepared as illustrated and described below.

16a para, R = 5-oxazolyl 17a para, R = 5-oxazolyl

16b meta, R = 5-oxazolyl 17b meta, R = 5-oxazolyl

16c para, R = CN

16d meta, R = CN

18a para, R = 5-oxazolyl 19a para, R = 5-oxazolyl

18b meta, R = 5-oxazolyl 19b meta, R = 5-oxazolyl

18c para, R = CN

18d meta, R = CN

Example 3 Preparation of compounds 16a-16d

20a para 21a para 20b meta 21 b meta

22a para 23a para 22b meta 23b meta a Reaction conditions: (a) tert-butyl acrylate, Pd(OAc)₂, P(0-tolyl)₃, NaOAc, DMF, 130 ⁰C; (b) NaBH₄, EtOH; (c) i. MsCl, Et₃N, THF; ii. NaN₃, DMF; iii. Ph₃P, THF/H₂O; iv. HCl, diethyl ether.

23a para 26a para, R = 5-oxazolyl 23b meta 26b meta , R = 5-oxazolyl

26c para, R = CN

26d meta , R = CN

27a para, R = 5-oxazolyl 27b meta, R = 5-oxazolyl 27c para, R = CN 27d meta, R = CN

28a para, R = 5-oxazolyl

28b meta, R = 5-oxazolyl

28c para, R = CN

28d meta, R = CN

16a para, R = 5-oxazolyl

16b meta, R = 5-oxazolyl

16c para, R = CN

16d meta, R = CN a Reaction conditions: (a) aniline 24 or 25, triphosgene, Et₃N, CH₂Cl₂; (b) TFA, CH₂Cl₂; (c) H₂N- OTr, EDC, HOBt, DMF; (d) TFA, Et₃SiH, CH₂Cl₂.

(£)-tert-Butyl 3-(4-formyIphenyl)acryIate (21a). A solution of 4-bromobenzaldehyde (20a, 9.33 g, 50.4 mmol), tert-butyl acrylate (10.9 mL, 75.1 mmol), Pd(OAc)₂ (226 mg, 1.01 mmol), P(O- tolyl)₃ (928 mg, 3.05 mmol), and NaOAc (8.49 g, 103 mmol) in dry DMF (100 mL) in a seal flask was evacuate and then back-filled with argon for five times. The mixture was heated at 130 ⁰C for 24 hours. After cooling to room temperature, the mixture was filtered through a pad of Celite and washed with EtOAc. After the filtrate was concentrated, the residue was dissolved in EtOAc (500 mL) and washed with water (2x200 mL), brine (2x200 mL). The organic layer was dried over Na₂SO₄ and filtered. The filtrate was concentrated and the residue was triturated with hot hexanes (100 mL). After filtration, aldehyde 21a was obtained as a white solid (8.08 g, 69%). ¹H NMR (CDCl₃, 600 MHz) δ 10.02 (s, IH), 7.89 (d, J= 7.8 Hz, 2H), 7.66 (d, J= 7.8 Hz, 2H), 7.61 (d, J= 16.2 Hz, IH), 6.48 (d, J= 16.2 Hz, IH), 1.54 (s, 9H).

(E)-tert-Buty\ 3-(3-formyIphenyl)acrylate (21b). Following procedures similar to those described for aldehyde 21a, 3-bromobenzaldehyde (20b, 5.90 mL, 50.4 mmol) was converted into aldehyde 21b as yellowish syrup (9.17 g, 78%). ¹H NMR (CDCl₃, 600 MHz) δ 10.01 (s, IH), 7.98 (s, IH), 7.84 (d, J= 7.8 Hz, IH), 7.72 (d, J= 7.8 Hz, IH), 7.60 (d, J= 16.2 Hz, IH), 7.53 (d, J= 7.5 Hz, IH), 6.44 (d, J= 16.2 Hz, IH), 1.51 (s, 9H).

(E)-tert-Buty\ 3-(4-(hydroxymethyl)phenyl)acryIate (22a). To a solution of aldehyde 21a (3.66 g, 15.8 mmol) in EtOH (100 mL) was added NaBH₄ (2.38 g, 62.9 mmol) in portions within 30 minutes. The resulting mixture was allowed to stir at room temperature for 1 hour and concentrated. The residue was dissolved in water (100 mL) and acidified to pH ~ 5. The solid formed was filtered, washed with water and then dried to give alcohol 22a as a white solid (3.05 g, 83%). ¹H NMR (CDCl₃, 600 MHz) δ 7.54 (d, J= 16.2 Hz, IH), 7.47 (d, J= 6.0 Hz, 2H), 7.34 (d, J = 6.0 Hz, 2H), 6.33 (d, J= 15.6 Hz, IH), 4.68 (s, 2H), 1.81 (brs, IH), 1.54 (s, 9H).

(E)-tert-Butyl 3-(3-(hydroxymethyl)phenyl)acryIate (22b). Following procedures similar to those described for alcohol 22a, aldehyde 21b (4.83 g, 20.8 mmol) was reduced with NaBH₄ (3.14 g, 83.0 mmol) to give alcohol 22b as a yellowish syrup (4.20 g, 86%). ¹H NMR (CDCl₃, 600 MHz) δ 7.54 (d, J= 15.6 Hz, IH), 7.48 (s, IH), 7.39 (t, J= 4.2 Hz, IH), 7.34-7.30 (m, 2H), 6.34 (d, J= 16.2 Hz, IH), 4.68 (s, 2H), 1.50 (s, 9H). (E)-tert-Buty\ 3-(4-(aminomethyl)phenyl)acrylate hydrochloride (23a). To a solution of alcohol 22a (2.98 g, 12.7 mmol) and Et₃N (3.60 mL, 25.8 mmol) in anhydrous THF (80 mL) at 0 ⁰C was added dropwise MsCl (1.50 mL, 19.3 mmol). The mixture was allowed to stir at 0 °C for 1 hour, warm to room temperature and stir at rt for 1 hour. After the reaction mixture was diluted with EtOAc (400 mL), the resulting solution was washed with water (100 mL), sat. NaHCO₃ (100 mL), water (100 mL) and brine (200 mL). The organic layer was dried over Na₂SO₄ and filtered. The filtrate was concentrated and re-dissolved in anhydrous DMF (60 mL). After NaN₃ (1.84 g, 28.3 mmol) was added at rt, the resulting mixture was heated at 50 ⁰C for 30 minutes and cooled to room temperature. The mixture was then diluted with EtOAc (300 mL) and washed with water (3x60 mL) and brine (2^χ 100 mL). The organic layer was dried over Na₂SO₄ and filtered. The filtrate was concentrated and re-dissolved in a mixture of THF (60 mL) and water (6 mL). After PPh₃ (4.34 g, 16.6 mmol) was added at room temperature, the reaction mixture was allowed to stir at room temperature overnight and then concentrated. The residue was dissolved in Et₂O (15 ml), and hexanes (200 mL) was added. The solid precipitated was filtered and washed with Et₂O/hexanes. The filtrate was concentrated and the residue was dissolved in hexanes (600 mL). After an addition of a solution of HCl in Et₂O (1.0 M, 30 mL), the solid precipitated was filtered, washed and dried to give amine hydrochloride 23a as a white solid (3.37 g, 98%). ¹H NMR (CD₃OD, 600 MHz) δ 7.66 (d, J= 8.4 Hz, 2H), 7.59 (d, J= 16.2 Hz, IH), 7.51 (d, J= 8.4 Hz, 2H), 6.48 (d, J= 16.2 Hz, IH), 4.15 (s, 2H), 1.53 (s, 9H). HRMS calcd for Ci₄H₂₀NO₂ 234.1488 (M+H)⁺, found 234.1495.

(E)-tert-Butyl 3-(3-(aminomethyl)phenyl)acrylate hydrochloride (23b). Following procedures similar to those described for amine 23a, alcohol 22b (3.86 g, 16.5 mmol) was converted into amine hydrochloride 23b as a white solid (4.33 g, 97%). ¹H NMR (CD₃OD, 600 MHz) δ 7.71 (s, IH), 7.60 (d, J= 16.2 Hz, IH), 7.56 (td, J= 7.5, 3.0 Hz, IH), 7.53-7.47 (m, 2H), 6.52 (d, J= 16.2 Hz, IH), 4.16 (s, 2H), 1.53 (s, 9H). HRMS calcd for C]₄H₂₀NO₂ 234.1488 (M+H)⁺, found 234.1506.

Preparation! of tβrt-Butyl ester 26a. To a solution of 3-methoxy-4-(oxazol-5-yl)aniline (456 mg, 2.40 mmol) in dry CH₂Cl₂ (25 mL) were added triphosgene (242 mg, 0.82 mmol) and then Et₃N (0.34 mL, 2.44 mmol). The resulting mixture was heated at reflux for lhour. After cooling to room temperature, additional Et₃N (1.0 niL, 7.2 mmol) was added, followed by an addition of (E)-tert- butyl 3-(4-(aminomethyl)phenyl)acrylate hydrochloride (777 mg, 2.88 mmol). The mixture was allowed to stir at it for 24 hours and then concentrated. The residue was dissolved in MeOH (15 mL) and slowly added to ice/water (150 mL plus 20 mL of IN HCl). The solid precipitate was washed with water, collected and purified by silica gel column chromatography to give tert-butyl ester 26a as a light-yellow solid (414 mg, 38%). ¹H NMR (CD₃OD, 600 MHz) δ 8.14 (s, IH), 7.62 (d, J= 9.0 Hz, IH), 7.58-7.52 (m, 3H), 7.44 (d, J= 1.8 Hz, IH), 7.40-7.35 (m, 3H), 6.92 (dd, J= 8.2, 1.8 Hz, IH), 6.40 (d, J= 15.6 Hz, IH), 4.42 (s, 2H), 3.92 (s, 3H), 1.52 (s, 9H). HRMS calcd for C₂₅H₂₇N₃O₅Na 472.1842 (M+Na)⁺, found 472.1810.

Preparation of tert-Butyl ester 26b. Following procedures similar to those described for tert-butyl ester 26a, (E)-tert-butyl 3-(3-(aminomethyl)phenyl)acrylate hydrochloride (776 mg, 2.88 mmol) was converted into tert-butyl ester 26b as a light-yellow solid (284 mg, 26%). ¹H NMR (CD₃OD, 600 MHz) δ 8.14 (s, IH), 7.62 (d, J= 8.4 Hz, IH), 7.57 (d, J= 16.2 Hz, IH), 7.55 (s, IH), 7.49-7.45 (m, IH), 7.44 (d, J= 1.8 Hz, IH), 7.40-7.36 (m, 3H), 6.92 (dd, J= 8.1, 2.1 Hz, IH), 6.44 (d, J= 15.6 Hz, IH), 4.42 (s, 2H), 3.94 (s, 3H), 1.52 (s, 9H). HRMS calcd for C₂₅H₂₇N₃O₅Na 472.1842 (M+Na)⁺, found 472.1802.

Preparation of tert-Butyl ester 26c. Following procedures similar to those described for tert-butyl ester 26a, ¹H NMR (CDCl₃, 600 MHz) δ 7.76 (s, IH), 7.59 (s, IH), 7.45 (d, J= 15.6 Hz, IH), 7.34- 7.30 (m, 3H), 7.28-7.24 (m, 2H), 6.63 (dd, J= 8.4, 1.2 Hz, IH), 6.24 (d, J= 16.2 Hz, IH), 5.86 (t, J = 5.7 Hz, IH), 4.43 (d, J= 5.4 Hz, 2H), 3.84 (s, 3H), 1.54 (s, 9H).

Preparation of tert-Butyl ester 26d. Following procedures similar to those described for tert-butyl ester 26a, ¹H NMR (CDCl₃, 600 MHz) δ 7.64 (s, IH), 7.57 (d, J= 1.2 Hz, 1H),7.46 (d, J= 16.2 Hz, IH), 7.36-7.24 (m, 6H), 6.62 (dd, J= 9.0, 1.2 Hz, IH), 6.30 (d, J= 15.6 Hz, IH), 5.77 (t, J= 5.7 Hz, IH), 4.40 (d, J= 6.0 Hz, 2H), 3.84 (s, 3H), 1.52 (s, 9H).

Preparation of Carboxylic acid 27a. A solution of tert-butyl ester 26a in dry CH₂Cl₂ (6 mL) and TFA (6 mL) was allowed to stir at rt overnight and then concentrated. After co-evaporation with toluene, carboxylic acid 27a was obtained as a light-yellow solid (292 mg, 99%). ¹H NMR (DMSO-d₅, 600 MHz) δ 8.92 (s, IH), 8.32 (s, IH), 7.67-7.58 (m, 3H), 7.56 (d, J= 16.2 Hz, IH), 7.53 (d, J= 8.4 Hz, IH), 7.43 (s, IH), 7.36 (s, IH), 7.33 (d, J= 7.8 Hz, 2H), 7.01 (d, J= 7.8 Hz, IH), 6.82 (t, J= 5.7 Hz, IH), 6.49 (d, J= 15.6 Hz, IH), 4.33 (d, J= 6.0 Hz, 2H), 3.87 (s, 3H). HRMS calcd for C_2IH₂₀N₃O₅ 394.1397 (M+H)⁺, found 394.1415.

Preparation of Carboxylic acid 27b. Following procedures similar to those described for carboxylic acid 27a, fert-butyl ester 26b (257 mg, 0.57 mmol) was converted into carboxylic acid 27b as a light-yellow solid (226 mg, 100%). ¹H NMR (DMSO-d₆, 600 MHz) δ 8.89 (s, IH), 8.31 (s, IH), 7.62-7.58 (m, 2H), 7.57-7.51 (m, 3H), 7.43 (s, IH), 7.40-7.33 (m, 3H), 7.01 (dd, J= 8.4, 1.8 Hz, IH), 6.80 (t, J= 5.7 Hz, IH), 6.50 (d, J= 15.6 Hz, IH), 4.33 (d, J= 5.4 Hz, 2H), 3.87 (s, 3H). HRMS calcd for C₂iH₂₀N₃O₅ 394.1397 (M+H)\ found 394.1413.

Preparation! of Carboxylic acid 27c. Following procedures similar to those described for carboxylic acid 27a, ¹H NMR (DMSO-d₆, 600 MHz) δ 12.36 (brs, IH), 9.25 (s, IH), 7.64 (d, J = 8.4 Hz, 2H), 7.56 (d, J= 15.6 Hz, IH), 7.51 (d, J= 9.0 Hz, IH), 7.46 (d, J= 1.2 Hz, IH), 7.32 (d, J = 7.8 Hz, 2H), 7.02-6.94 (m, 2H), 6.49 (d, J= 15.6 Hz, IH), 4.32 (d, J= 6.0 Hz, 2H), 3.83 (s, 3H).

Preparation! of Carboxylic acid 27d. Following procedures similar to those described for carboxylic acid 27a, ¹H NMR (DMSO-d₆, 600 MHz) δ 9.21 (s, IH), 7.59 (d, J= 6.0 Hz, IH), 7.55 (d, J= 5.4 Hz, IH), 7.51 (d, J= 9.0 Hz, IH), 7.46 (s, IH), 7.38 (t, J= 7.5 Hz, IH), 7.34 (d, J= 7.2 Hz, IH), 6.98 (dd, J= 9.0, 1.2 Hz, IH), 6.94 (t, J= 5.7 Hz, IH), 6.50 (d, J= 16.2 Hz, IH), 4.32 (d, J = 5.4 Hz, 2H), 3.83 (s, 3H).

Preparation of Protected hydroxamate 28a. A solution of carboxylic acid 27a (272 mg, 0.69 mmol), l-ethyl-3-3(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC, 410 mg, 2.07 mmol), 1-hydroxy-benzotriazole (HOBt, 189 mg, 1.40 mmol) and Otritylhydroxylamine (380 mg, 1.38 mmol) in anhydrous DMF (10 mL) was stirred at rt for 4 d. After concentration, the residue was diluted with EtOAc (60 mL) and washed with water (10 mL), sat. NaHCO₃ (10 mL), water (10 mL) and brine (30 mL). The organic layer was dried over Na₂SO₄ and filtered. The filtrate was concentrated and the residue was purified by silica gel column chromatography (0-4% MeOH/CH₂Cl₂) to give protected hydroxamate 28a as a yellowish solid (281 mg, 62%). ¹H NMR (DMSOd₆, 600 MHz) δ 10.37 (s, IH), 8.84 (s, IH), 8.32 (s, IH), 7.53 (d, J= 8.4 Hz, IH), 7.48-7.40 (m, 3H), 7.40-7.18 (m, 18H), 7.00 (d, J= 8.4 Hz, IH), 6.71 (t, J= 5.7 Hz, IH), 6.44 (d, J= 16.2 Hz, IH), 4.29 (d, J= 5.4 Hz, 2H), 3.86 (s, 3H). HRMS calcd for C₄₀H₃₄N₄O₅Na 673.2421 (M+Na)⁺, found 673.2421.

Preparation! of Protected hydroxamate 28b. Following procedures similar to those described for protected hydroxamate 28a, carboxylic acid 27b (206 mg, 0.52 mmol) was converted into protected hydroxamate 28b as a yellowish solid (71 mg, 21%). ¹H NMR (DMSO-d₆, 600 MHz) δ 10.42 (s, IH), 8.81 (s, IH), 8.32 (s, IH), 7.53 (d, J= 8.4 Hz, IH), 7.44-7.18 (m, 21H), 7.00 (d, J= 8.4 Hz, IH), 6.71 (t, J= 5.7 Hz, IH), 6.47 (d, J= 15.6 Hz, IH), 4.29 (d, J= 6.0 Hz, 2H), 3.86 (s, 3H). HRMS calcd for C₄₀H₃₄N₄O₅Na 673.2421 (M+Na)⁺, found 673.2422.

Preparation of Protected hydroxamate 28c. Following procedures similar to those described for protected hydroxamate 28a, ¹H NMR (DMSO-d₆, 600 MHz) δ 10.39 (s, IH), 9.20 (s, IH), 7.56- 7.16 (m, 21H), 6.98 (d, J= 6.0 Hz, IH), 6.89 (s, IH), 6.45 (d, J= 14.4 Hz, IH), 4.29 (s, 2H), 3.82 (s, 3H).

Preparation! of Protected hydroxamate 28d. Following procedures similar to those described for protected hydroxamate 28a, ¹H NMR (DMSO-d₆, 600 MHz) δ 10.44 (s, IH), 9.16 (s, IH), 7.51 (d, J= 8.4 Hz, IH), 7.45 (s, IH), 7.42-7.18 (m, 20H), 6.97 (d, J= 6.6 Hz, IH), 6.88 (s, IH), 6.48 (d, J= 15.6 Hz, IH), 4.28 (d, J= 4.8 Hz, 2H), 3.82 (s, 3H).

Preparation of Hydroxamic acid 16a. To a suspension of protected hydroxamate 28a (256 mg, 0.39 mmol) in anhydrous CH₂Cl₂ (10 mL) was added TFA (0.50 mL). The resulting yellow solution was treated with Et₃SiH till there was no change of color. After stirring for additional 40 min, the solid precipitate was filtered, washed with CH₂Cl₂ and collected to give hydroxamic acid 16a as a yellowish solid (151 mg, 94%). ¹H NMR (DMSO-d₆, 600 MHz) δ 8.88 (s, IH), 8.32 (s, IH), 7.56- 7.48 (m, 3H), 7.45-7.39 (m, 2H), 7.36 (s, IH), 7.33 (d, J= 7.8 Hz, 2H), 7.01 (dd, J= 9.0, 1.2 Hz, IH), 6.76 (brs, IH), 6.43 (d, J= 16.2 Hz, IH), 4.32 (d, J= 4.2 Hz, 2H), 3.87 (s, 3H). HRMS calcd for C₂]H₂IN₄O₅ 409.1506 (M+H)⁺, found 409.1500.

Preparation of Hydroxamic acid 16b. Following procedures similar to those described for hydroxamic acid 16a, protected hydroxamate 28b (56 mg, 0.086 mmol) was converted into hydroxamic acid 16b as a pale solid (34 mg, 97%) ¹H NMR (DMSOd₆, 600 MHz) δ 8.86 (s, IH), 8.32 (s, IH), 7.54 (d, J= 8.4 Hz, IH), 7.48 (s, IH), 7.46-7.40 (m, 3H), 7.38 (d, J= 7.8 Hz, IH), 7.36 (s, IH), 7.31 (d, J= 7.8 Hz, IH), 7.02 (d, J= 8.4 Hz, IH), 6.77 (brs, IH), 6.45 (d, J= 15.6 Hz, IH), 4.32 (d, J= 4.2 Hz, 2H), 3.87 (s, 3H). HRMS calcd for C₂iH₂iN₄O₅ 409.1506 (M+H)⁺, found 409.1506.

Preparation of Hydroxamic acid 16c. Following procedures similar to those described for hydroxamic acid 16a, ¹H NMR (DMSOd₆, 600 MHz) δ 9.22 (s, IH), 7.55-7.48 (m, 3H), 7.46 (s, IH), 7.42 (d, J= 15.6 Hz, IH), 7.32 (d, J= 7.2 Hz, 2H), 6.98 (d, J= 8.4 Hz, IH), 6.93 (s, IH), 6.42 (d, J= 15.6 Hz, IH), 4.31 (d, J= 4.2 Hz, 2H), 3.83 (s, 3H).

Preparation! of Hydroxamic acid 16d. Following procedures similar to those described for hydroxamic acid 16a, ¹H NMR (DMSO-d₆, 600 MHz) δ 9.21 (s, IH), 7.51 (d, J= 9.0 Hz, IH), 7.48-7.40 (m, 4H), 7.37 (t, J= 7.5 Hz, IH), 7.30 (d, J= 7.2 Hz, IH), 6.99 (d, J= 8.4 Hz, IH), 6.94 (t, J= 6.0 Hz, IH), 6.44 (d, J= 15.6 Hz, IH), 4.32 (d, J= 5.4 Hz, 2H), 3.83 (s, 3H).

Starting aniline 24,

24 can be prepared as described by Gu, H. H., et al. Bioorg. Med. Lett. 2002, 12, 1323-1326.)

Starting Aniline 25,

25 can be prepared as described by Mackman, R. L., et al. J. Med. Chem. 2001, 44, 3856-3871.)

Example 4 Preparation of compounds 17a-17b

23a para 30a para 23b meta 30b meta

31a para 31b meta

32a para 32b meta

17a para 17b meta a Reaction conditions: (a) compound 29, PyBOP, NMM, DMF; (b) TFA, CH₂Cl₂; (c) H₂N-OTr, EDC, HOBt. DMF; (d) TFA, Et₃SiH, CH₂Cl₂. Preparation of tert-Butyl ester 30a. A solution of (E)-tert-butyl 3-(4-

(aminomethyl)phenyl)acrylate hydrochloride (23a, 405 mg, 1.50 mmol), 2-(3-methoxy-4-(oxazol-5- yl)phenylamino)-2-oxoacetic acid (29, 472 mg, 1.80 mmol), PyBOP (1.17 g, 2.25 mmol) and NMM (0.66 mL, 6.00 mmol) in anhydrous DMF (15 mL) was stirred at it for 48 h. The reaction mixture was slowly added to ice/water (150 mL plus 20 mL of IN HCl). The solid precipitate was washed with water, collected and purified by silica gel column chromatography (30-50% EtOAc/hexanes) to give tert-butyl ester 30a as a yellow solid (298 mg, 42%). ¹H NMR (CDCl₃, 600 MHz) δ 9.38 (s, IH), 7.92 (t, J= 5.7 Hz, IH), 7.90 (s, IH), 7.75 (d, J= 7.8 Hz, IH), 7.60-7.54 (m, 2H), 7.53 (s, IH), 7.50 (d, J= 8.4 Hz, 2H), 7.32 (d, J= 8.4 Hz, 2H), 7.17 (dd, J= 8.4, 1.8 Hz, IH), 6.36 (d, J= 15.6 Hz, IH), 4.58 (d, J= 6.0 Hz, 2H), 3.98 (s, 3H), 1.54 (s, 9H). HRMS calcd for C₂₆H₂₇N₃O₆Na 500.1792 (M+Na)⁺, found 500.1793.

Preparation of tert-Butyl ester 30b. Following procedures similar to those described for tert-butyl ester 30a, (E)-tert-butyl 3-(3-(aminomethyl)phenyl)acrylate hydrochloride (405 mg, 1.50 mmol) was converted into tert-butyl ester 30b as a yellow solid (305 mg, 42%). ¹H NMR (CDCl₃, 600 MHz) δ 9.38 (s, IH), 7.92 (t, J= 5.7 Hz, IH), 7.90 (s, IH), 7.76 (d, J= 8.4 Hz, IH), 7.60-7.52 (m, 3H), 7.48-7.42 (m, 2H), 7.37 (t, J= 7.5 Hz, IH), 7.31 (d, J= 7.8 Hz, 2H), 7.18 (dd, J= 8.4, 1.8 Hz, IH), 6.38 (d, J= 16.2 Hz, IH), 4.58 (d, J= 6.0 Hz, 2H), 3.98 (s, 3H), 1.53 (s, 9H). HRMS calcd for C₂₆H₂₇N₃O₆Na 500.1792 (M+Na)⁺, found 500.1797.

Preparation! of Carboxylic acid 31a. A solution of tert-butyl ester 30a in dry CH₂Cl₂ (6 mL) and TFA (6 mL) was allowed to stir at rt overnight and then concentrated. After co-evaporation with toluene, carboxylic acid 31a was obtained as a yellow solid (240 mg, 100%). ¹H NMR (DMSO-d₆, 600 MHz) δ 10.79 (s, IH), 9.59 (t, J= 6.6 Hz, IH), 8.38 (s, IH), 7.75 (s, IH), 7.68-7.61 (m, 4H), 7.56 (d, J= 15.6 Hz, IH), 7.47 (s, IH), 7.34 (d, J= 8.4 Hz, 2H), 6.49 (d, J= 16.2 Hz, IH), 4.42 (d, J = 6.0 Hz, 2H), 3.90 (s, 3H). HRMS calcd for C₂₂H₂₀N₃O₆ 422.1346 (M+H)⁺, found 422.1350.

Preparation of Carboxylic acid 31b. Following procedures similar to those described for carboxylic acid 31a, tert-butyl ester 30b (280 mg, 0.59 mmol) was converted into carboxylic acid 31b as a yellow solid (240 mg, 97%). ¹H NMR (DMSO-d₆, 600 MHz) δ 10.79 (s, IH), 9.56 (t, J= 6.3 Hz, IH), 8.38 (s, IH), 7.76 (s, IH), 7.69-7.60 (m, 3H), 7.60-7.53 (m, 2H), 7.47 (s, IH), 7.40- 7.32 (m 2H), 6.50 (d, J= 16.2 Hz, IH), 4.43 (d, J= 6.0 Hz, 2H), 3.90 (s, 3H). HRMS calcd for C₂₂H₂₀N₃O₆ 422.1346 (M+H)⁺, found 422.1346.

Preparation, of Protected hydroxamate 32a. A solution of carboxylic acid 31a (215 mg, 0.51 mmol), EDC (310 mg, 1.57 mmol), HOBt (139 mg, 1.03 mmol) and 0-tritylhydroxylamine (281 mg, 1.02 mmol) in anhydrous DMF (15 mL) was stirred at rt for 4 d. After concentration, the residue was dissolved in MeOH (15 mL) and slowly added to ice/water (150 mL). The solid precipitate was washed with water, collected and purified by silica gel column chromatography (0- 4% MeOH/CH₂Cl₂) to give protected hydroxamate 32a as a light-yellow solid (281 mg, 81%). ¹H NMR (CDCi₃, 600 MHz) δ 9.38 (s, IH), 7.94-7.86 (m, 2H), 7.75 (d, J= 7.8 Hz, IH), 7.57 (d, J= 1.2 Hz, IH), 7.53 (s, IH), 7.43 (brs, 5H), 7.36-7.31 (m, 7H), 7.31-7.26 (m, 4H), 7.24 (d, J= 7.8 Hz, 2H), 7.18 (dd, J= 8.7, 1.5 Hz, IH), 6.09 (d, J= 16.2 Hz, IH), 4.54 (d, J= 6.6 Hz, 2H), 3.98 (s, 3H). HRMS calcd for C₄₁H₃₄N₄O₆Na 701.2370 (M+Na)⁺, found 701.2366.

Preparation of Protected hydroxamate 32b. Following procedures similar to those described for protected hydroxamate 32a, carboxylic acid 31b (215 mg, 0.51 mmol) was converted into protected hydroxamate 32b as a light-yellow solid (200 mg, 58%). ¹H NMR (CDCl₃, 600 MHz) δ 9.35 (s, IH), 7.93-7.84 (m, 2H), 7.76 (d, J= 8.4 Hz, IH), 7.56 (d, J= 1.8 Hz, IH), 7.53 (s, IH), 7.43 (brs, 5H), 7.36-7.31 (m, 7H), 7.30-7.23 (m, 6H), 7.16 (dd, J= 8.1, 1.5 Hz, IH), 6.10 (d, J= 15.6 Hz, IH), 4.53 (d, J= 6.0 Hz, 2H), 3.97 (s, 3H). HRMS calcd for C₄iH₃₄N₄O₆Na 701.2370 (M+Na)⁺, found 701.2369.

Preparation of Hydroxamic acid 17a. To a solution of protected hydroxamate 32a (250 mg, 0.37 mmol) in anhydrous CH₂Cl₂ (10 mL) was added TFA (0.50 mL). The resulting yellow solution was treated with Et₃SiH till there was no change of color. After stirring for additional 30 min, the solid precipitate was filtered, washed with CH₂Cl₂ and collected to give hydroxamic acid 17a as a yellowish solid (151 mg, 94%). ¹H NMR (DMSO-d₆, 600 MHz) δ 10.79 (s, IH), 9.58 (t, J= 6.3 Hz, IH), 8.39 (s, IH), 7.75 (s, IH), 7.68-7.61 (m, 2H), 7.52 (d, J= 7.8 Hz, 2H), 7.48 (s, IH), 7.42 (d, J = 16.2 Hz, IH), 7.33 (d, J= 7.8 Hz, 2H), 6.43 (d, J= 15.6 Hz, IH), 4.41 (d, J= 6.6 Hz, 2H), 3.90 (s, 3H). HRMS calcd for C₂₂H_2IN₄O₆ 437.1455 (M+H)⁺, found 437.1451. Preparation of Hydroxamic acid 17b. Following procedures similar to those described for hydroxamic acid 17a, protected hydroxamate 32b (175 mg, 0.26 mmol) was converted into hydroxamic acid 17b as a pale solid (105 mg, 93%). ¹H NMR (DMSO-d₆, 600 MHz) δ 10.79 (s, IH), 9.58 (t, J= 6.0 Hz, IH), 8.38 (s, IH), 7.76 (s, IH), 7.69-7.61 (m, 2H), 7.50 (s, IH), 7.48 (s, IH), 7.46-7.40 (m, 2H), 7.37 (t, J= 7.5 Hz, IH), 7.31 (d, J= 7.2 Hz, IH), 6.45 (d, J= 15.6 Hz, IH), 4.42 (d, J= 6.6 Hz, 2H), 3.91 (s, 3H). HRMS calcd for C₂₂H₂₁N₄O₆ 437.1455 (M+H)⁺, found 437.1450.

Starting compound 29,

29 can be prepared as described by Gu, H. H., et al. Bioorg. Med. Lett. 2002, 12, 1323-1326.

Example 5 Preparation of compounds 18a-18d

33a para 34a para, R = 5-oxazolyl 33b meta 34b meta, R = 5-oxazolyl

34c para, R = CN

34d meta, R = CN

35a para, R = 5-oxazolyl 35b meta, R = 5-oxazolyl 35c para, R = CN 35d meta, R = CN

36a para, R = 5-oxazolyl 36b meta, R = 5-oxazolyl 36c para, R = CN 36d meta, R = CN

18a para, R = 5-oxazolyl 18b meta, R = 5-oxazolyl 18c para, R = CN 18d meta, R = CN a Reaction conditions: (a) aniline 24 or 25, triphosgene, Et₃N, CH₂Cl₂; (b) TFA, CH₂Cl₂; (c) H₂N- OTr, EDC, HOBt, DMF; (d) TFA, Et₃SiH, CH₂Cl₂. Preparation of Ethyl ester 34a. To a solution of 3-methoxy-4-(oxazol-5-yl) aniline (570 mg, 3.0 mmol) and triphosgene (296 mg, 1.0 mmol) in CH₂Cl₂ (10 mL) was added Et₃N (0.50 mL, 5.0 mmol) at 5 ⁰C and the mixture was refluxed for 2.5 h. The mixture was cooled to room temperature and a solution of ethyl 4-aminocinnamate hydrochloride (33a, 555 mg, 2.0 mmol) in CH₂Cl₂ was added. Additional Et₃N (0.25 mL) was added and the mixture was stirred at rt for 2.5 h and then poured into water. The product was extracted with EtOAc and purified on silica gel column (Hexanes: EtOAc: MeOH = 6:3:1) to obtain ethyl ester 34a (410 mg, 50%). ¹H NMR (DMSO-d₆, 600 MHz): δ 9.91 (s, IH), 8.99 (s, IH), 8.36 (s, IH), 7.65 (d, J= 8.4 Hz, 2H), 7.61 (d, J= 8.4 Hz, IH), 7.58 (d, J= 16.2 Hz, IH), 7.52 (d, J= 8.4 Hz, 2H), 7.46 (s, IH), 7.42 (s, IH), 7.08 (dd, J= 8.4, 1.2 Hz, IH), 6.48 (d, J= 16.2 Hz, IH), 4.18 (q, J= 7.2 Hz, 2H), 3.93 (s, 3H), 1.25 ( t, J= 7.2 Hz, IH). ¹³C NMR (DMSO-d₆): δ 167.1, 156.5, 152.8, 150.9, 147.9, 144.8, 142.4, 141.7, 130.0, 128.4, 126.6, 124.1, 118.8, 116.3, 111.1, 110.8, 101.8, 102.1, 60.5, 56.1, 14.9. HRMS calcd for C₂₂H₂IN₃O₅Na 430.1373 (M+Na)⁺, found 430.1385.

Preparation of Ethyl ester 34b. Following procedures similar to those described for ethyl ester 34a, 3-methoxy-4-(oxazol-5-yl) aniline (24, 570 mg, 3.0 mmol) and ethyl 3-aminocinnamate (33b, 382 mg, 2.0 mmol) were combined to give ethyl ester 34b (220 mg, 27%). ¹H NMR (DMSO-d₆, 600 MHz): δ 8.13 (s, IH), 7.71 (s, IH), 7.57 (d, J= 8.4 Hz, 2H), 7.56 (d, J= 15.6 Hz, IH), 7.44 (s, IH), 7.40 (d, J= 7.2 Hz, IH), 7.34 (d, J= 1.2 Hz, IH), 7.28 (t, J= 7.8 Hz, IH), 7.21 (d, J= 7.8 Hz, IH), 6.97 (d, J= 8.4 Hz, IH), 6.43 (d, J= 15.6 Hz, IH), 4.14 (q, J= 7.2 Hz, 2H), 3.89 (s, 3H), 1.22 ( t, J= 7.2 Hz, 3H). ¹³C NMR (DMSO-d₆): δ 166.8, 156.6, 153.1, 150.3, 148.2, 144.7, 141.5, 140.3, 135.3, 129.7, 126.3, 123.5, 122.5, 120.9, 118.6, 118.1, 110.9, 110.8, 101.8, 60.5, 55.3, 13.9. HRMS calcd for C₂₂H₂₂N₃O₅ 408.1553 (M+H)⁺, found 408.1561.

Preparation of Ethyl ester 34c. Following procedures similar to those described for ethyl ester 34a, 4-cyano-3-methoxy aniline hydrochloride (25, 554 mg, 3.0 mmol) and ethyl 4-aminocinnamate hydrochloride (33a, 555 mg, 2.0 mmol) were combined to give ethyl ester 34c (710 mg, 97%). ¹H NMR (DMSO-dβ, 600 MHz): δ 9.29 (s, IH), 9.11 (s, IH), 7.66 (d, J= 8.4 Hz, 2H), 7.59 (d, J= 15.6 Hz, IH), 7.58 (d, J= 7.2 Hz, IH), 7.52 (d, J= 9.0 Hz, 2H), 7.49 (s, IH), 7.04 (d, J= 8.4 Hz, IH), 6.50 (d, J= 15.6 Hz, IH), 4.17 (q, J= 7.2 Hz, 2H), 3.88 (s, 3H), 1.25 (t, J= 7.2 Hz, IH). ¹³C NMR (DMSO-de): δ 167.1, 162.4, 152.5, 146.4, 144.8, 141.9, 134.8, 130.0, 128.7, 119.0, 117.6, 116.6, 111.1, 101.5, 93.5, 60.5, 56.6, 14.9. HRMS calcd for C₂₀Hi₉N₃O₄Na 388.1267 (M+Na)⁺, found 388.1281.

Preparation of Ethyl ester 34d. Following procedures similar to those described for ethyl ester 34a, 4-cyano-3-methoxy aniline hydrochloride (25, 369 mg, 2.0 mmol) and ethyl 3-aminocinnamate (33b, 573 mg, 3.0 mmol) were combined to give ethyl ester 34d (485 mg, 66%). ¹H NMR (DMSO- de, 600 MHz): δ 9.29 (s, IH), 8.90 (s, IH), 7.74 (s, IH), 7.60 (d, J= 15.6 Hz, IH), 7.57 (d, J= 9.0 Hz, IH), 7.50 (s, IH), 7.48 (d, J= 6.6 Hz, IH), 7.38 (d, J= 7.2 Hz, IH), 7.35 (t, J= 6.8 Hz, IH), 7.01 (dd, J= 7.8, 1.2 Hz, IH), 6.52 (d, J= 16.2 Hz, IH), 4.16 (q, J= 7.2 Hz, 2H), 3.87 (s, 3H), 1.25 ( t, J= 7.2 Hz, IH). ¹³C NMR (DMSO-d₆): δ 166.0, 161.7, 152.1, 145.9, 144.3, 139.6, 134.6, 134.1,

129.4, 122.2, 120.7, 118.4, 118.3, 1 16.9, 110.3, 100.7, 92.7, 60.1, 55.9, 14.1. HRMS calcd for C₂₀H₁₉N₃O₄Na 388.1267 (M+Na)⁺, found 388.1284.

Preparation! of Carboxylic acid 35a. To a suspension of ethyl ester 34a (300 mg, 0.74 mmol) in THF (5 mL) was added methanol (2.5 mL) and NaOH (590 mg, 15 mmol in 5 mL of water). The mixture was stirred at room temperature overnight. After solvents were removed, the residue was diluted with water and pH was adjusted with aqueous HCl to 1-2. The precipitate of the product was filtered, collected and dried to give carboxylic acid 35a (245 mg, 87%). ¹H NMR (DMSO-d₆, 600 MHz): δ 9.01 (brs, 2H), 8.34 (s, IH), 7.53-7.61 (m, 5H), 7.45 (d, J= 16.2 Hz, IH), 7.48-7.56 (m, 2H), 7.08 (d, J= 6.6 Hz, IH), 6.40 (d, J= 16.2 Hz, IH), 3.92 (s, 3H). ¹³C NMR (DMSO-d₆): δ

168.5, 156.5, 152.9, 150.9, 147.9, 146.7, 144.5, 142.2, 141.8, 129.9, 128.6, 126.6, 124.1, 118.8, 117.4, 113.4, 1 11.1, 110.9, 102.1, 56.2. HRMS calcd for C₂₀Hi₈N₃O₅ 380.1240 (M+H)⁺, found 380.1233. Preparation of Carboxylic acid 35b. Following procedures similar to those described for carboxylic acid 35a, ethyl ester 34b (580 mg, 1.43 mmol) underwent hydrolysis to give carboxylic acid 35b (360 mg, 66%). ¹H NMR (DMSO-d₆, 600 MHz): δ 9.91 (s, IH), 9.80 (s, IH), 8.34 (s, IH), 7.76 (s, IH), 7.58 (d, J= 7.2 Hz, IH), 7.56 (d, J= 14.4 Hz, IH), 7.48-7.56 (m, 2H), 7.40 (s,lH), 7.29-7.31 (m, 2H), 7.05 (d, J= 6.8 Hz, IH), 6.43 (d, J= 15.6 Hz, IH), 3.91 (s, 3H). ¹³C NMR (DMSO-d₆): δ 166.9, 155.3, 152.2, 149.7, 146.8, 143.5, 141.0, 139.8, 134.2, 128.9, 125.4, 122.7,

121.3, 119.4, 118.7, 116.6, 109.6, 109.3, 100.4, 54.9. HRMS calcd for C₂₀Hi₈N₃O₅ 380.1240 (M+H)⁺, found 380.1233.

Preparation of Carboxylic acid 35c. Following procedures similar to those described for carboxylic acid 35a, ethyl ester 34c (365 mg, 1.0 mmol) underwent hydrolysis to give carboxylic acid 35c as a yellow solid (330 mg, 98%). ¹H NMR (DMSO-d₆, 600 MHz): δ 12.2 (brs, IH), 10.1 (brs, IH), 9.91 (brs, IH), 7.62 (d, J= 8.4 Hz, 2H), 7.58 (d, J= 8.4 Hz, IH), 7.49-7.53 (m, 4H), 7.02 (dd, J= 8.4, 1.2 Hz, IH), 6.40 (d, J= 16.2 Hz, IH), 3.88 (s, 3H). ¹³C NMR (DMSOd₆): δ 168.5,

162.4, 152.8, 146.6, 144.4, 141.9, 134.8, 129.9, 118.7, 117.7, 117.5, 113.4, 110.8, 101.1, 93.3, 56.6. HRMS calcd for Ci₈H₁₅N₃O₄Na 360.0954 (M+Na)⁺, found 360.0965.

Preparation! of Carboxylic acid 35d. Following procedures similar to those described for carboxylic acid 35a, ethyl ester 34d (365 mg, 1.0 mmol) underwent hydrolysis to give carboxylic acid 35d (250 mg, 74%). ¹H NMR (DMSO-d₆, 600 MHz): δ 6.99 (s, IH), 6.83 (d, J= 15.6 Hz, IH), 6.79 (s, IH), 6.72 (t, J= 10.2, 8.4 Hz, 2H), 6.58 (t, J= 7.8 Hz, IH), 6.51 (d, J= 7.2 Hz, IH), 6.23 (d, J= 10.2 Hz, IH), 5.70 (d, J= 15.6 Hz, IH), 4.16 (q, J= 7.2 Hz, 2H), 3.78 (s, 3H). ¹³C NMR (DMSO-d₆): δ 168.8, 162.7, 153.1, 146.4, 144.8, 140.1, 135.7, 134.4, 129.8, 123.0, 121.2, 119.5, 118.5, 117.2, 110.9, 101.4, 94.1, 55.9. HRMS calcd for Ci₈Hj₅N₃O₄Na 360.0954 (M+Na)⁺, found 360.0963.

Preparation of Hydroxamic acid 18a. To a solution of carboxylic acid 35a (100 mg, 0.26 mmol) in dried DMF (5 mL) was added O-tritylhydroxylamine (109 mg, 1.5mmol), EDC (101 mg, 0.52 mmol) and 1-hydroxybenzotriazole (53 mg, 0.40 mmol). The mixture was stirred at room temperature overnight. Solvent was removed and the residue was purified on silica gel column (CHCl₃: MeOH= 9: 1) to give protected hydroxamate 36a (70 mg, 42%). To a portion of 36a (64 mg, 0.10 mmol) in CH₂Cl₂ (5 mL) was added TFA (0.25 niL) and triethylsilane (0.25 mL). The mixture was allowed to stir overnight. The precipitate was filtered, collected and dried to give hydroxamic acid 18a (38 mg, 96%). ¹H NMR (DMSO-d₆, 600 MHz): δ 9.05 (s, IH), 9.00 (s, 1 H), 8.36 (s, IH), 7.60 (d, J= 8.4 Hz, IH), 7.48-7.53 (m, 5H), 7.42 (d, J= 12.0 Hz , IH), 7.39 (d, J = 10.2 Hz, IH), 7.07 (d, J= 8.4 Hz, IH), 6.35 (d, J= 15.6 Hz, IH), 3.92 (s, 3H). ¹³C NMR (DMSO- d₆): 6 213.6, 180.2, 156.4, 152.8, 146.7, 141.8, 129.0, 126.6, 118.9, 113.3, 111.0, 110.8, 102.2, 56.1. HRMS calcd for C₂₀Hi₉N₄O₅ 395.1349 (M+H)⁺, found 395.1331.

Preparation of Hydroxamic acid 18b. Following procedures similar to those described for hydroxamic acid 18a, carboxylic acid 35b (100 mg, 0.26 mmol) was converted into protected hydroxamate 36b (90 mg, 54%). A portion of 36b (64 mg, 0.10 mmol) was deprotected to give hydroxamic acid 18b (37 mg, 93%). ¹H NMR (DMSO-d₆, 600 MHz): δ 9.02 (s, IH), 8.87 (s, IH), 8.35 (s, IH), 7.78 (s, IH), 7.61 (d, J= 9.0 Hz, IH), 7.38-7.45 (m, 4H), 7.32 (t, J= 7.8 Hz , 2H), 7.17 (d, J= 7.8 Hz, IH), 7.08 (d, J= 7.8 Hz, IH), 6.43 (d, J= 16.2 Hz, IH), 3.92 (s, 3H). ¹³C NMR (DMSO-d₆): δ 162.6, 158.5, 152.4, 150.2, 147.2, 141.2, 140.0, 138.4, 135.4, 129.4, 125.9, 123.3, 121.8, 119.6, 116.5, 110.3, 110.0, 101.3, 55.4. HRMS calcd for C₂₀Hi₉N₄O₅ 395.1349 (M+H)⁺, found 395.1339.

Preparation! of Hydroxamic acid 18c. Following procedures similar to those described for hydroxamic acid 18a, carboxylic acid 35c (100 mg, 0.30 mmol) was converted into protected hydroxamate 36c (85 mg, 48%). A portion of 36c (60 mg, 0.10 mmol) was deprotected to give hydroxamic acid 18c (25 mg, 71%). ¹H NMR (DMSO-d₆, 600 MHz): δ 10.7 (s, IH), 9.31 (s, IH), 9.10 (s, IH), 8.98 (s, IH), 7.59 (d, J= 9.0 Hz, IH), 7.50 (brs, 5H), 7.40 (d, J= 15.6 Hz, IH), 7.03 (d, J= 8.4 Hz, IH), 6.35 (d, J= 16.2 Hz, IH), 3.88 (s, 3H). ¹³C NMR (DMSO-d₆): δ 162.4, 152.6, 146.7, 146.5, 141.0, 138.7, 134.8, 129.6, 129.0, 119.2, 117.6, 113.3, 111.0, 101.4, 93.4, 56.6. HRMS calcd for Ci₈Hi₆N₄O₄Na 375.1063 (M+Na)⁺, found 375.1065.

Preparation of Hydroxamic acid 18d. Following procedures similar to those described for hydroxamic acid 18a, carboxylic acid 35d (100 mg, 0.30 mmol) was converted into protected hydroxamate 36d. A portion of 36d (60 mg, 0.10 mmol) was deprotected to give hydroxamic acid 18d (32 mg, 90%). ¹H NMR (DMSO-d₆, 600 MHz): δ 9.30 (s, IH), 8.99 (s, IH), 7.76 (s, IH), 7.58 (d, J= 8.4 Hz, IH), 7.48 (s, IH), 7.41 (d, J= 15.6 Hz, IH), 7.39 (d, J= 11.4 Hz, IH), 7.33 (t, J= 7.8, 7.2 Hz, IH), 7.19 (d, J= 7.8 Hz, IH), 7.04 (d, J= 8.4 Hz, IH), 6.43 (d, J= 15.6 Hz, IH), 3.88 (s, 3H). ¹³C NMR (DMSOd₆): δ 161.7, 152.1, 145.9, 139.6, 138.3, 135.4, 134.1, 129.4, 122.1, 119.8, 119.2, 116.9, 116.8, 110.3, 100.7, 92.7, 55.9. HRMS calcd for Ci₈Hi₆N₄O₄Na 375.1063 (M+Na)⁺, found 375.1055.

Example 6 Preparation of compounds 19a-19b

a Reaction conditions: (a) compound 29, PyBOP, NMM, DMF; (b) TFA, CH₂Cl₂; (c) H₂N-OTr, EDC, HOBt, DMF; (d) TFA, Et₃SiH, CH₂Cl₂. Preparation of Ethyl ester 37a. To a solution of 2-(3-methoxy-4-(oxazol-5-yl)phenylamino)-2- oxoacetic acid (29, 600 mg, 2.29 mmol) in anhydrous DMF (15 niL) were added benzotriazol-1- yloxy-tripyrrolidinophosphonium hexafluorophosphate (PyBOP) (2.38 g, 4.56 mmol), 4- methylmorpholine (NMM) (1.10 mL, 9.16 mmol) and (E)-ethyl 3-(4-aminophenyl)acrylate (33a, 525 mg, 2.75 mmol). The mixture was stirred at rt for 48 h. After concentration, the resulting residue was diluted with EtOAC (50 mL) and subsequently washed with H₂O (2x 10 mL) and brine (2 x 10 mL). The organic layer was dried over Na₂SO₄ and filtered. The filtrate was concentrated and the residue was purified by flash chromatography column (0%-3% MeOH/CH₂Cl₂) to give ethyl ester 37a as a light yellow solid (500 mg, 50%). mp = 187.6-188.1 ⁰C. ¹H NMR (DMSO-d₆, 600 MHz): 511.04 (s, IH), 11.01 (s, IH), 8.38 (s, IH), 7.91 (d, J= 8.51 Hz, IH), 7.82 (s, IH), 7.72 (d, J = 8.2 Hz, IH), 7.67 (d, J= 8.5 Hz, 2H), 7.63 (d, J= 8.2 Hz, 2H), 7.61 (d, J= 16.1 Hz, IH), 7.48 (s, IH), 6.58 (d, J= 15.8 Hz, IH), 4.17 (q, J= 6.7 Hz, 2H), 3.91 (s, 3H), 1.23 ( t, J= 6.3 Hz, 3H). HRMS calcd for C₂₃H₂₂N₃O₆ 436.2054 (M + H)⁺, found 436.2058.

Preparation of Ethyl ester 37b. Following procedures similar to those described for ethyl ester 37a, oxoacetic acid 29 (200 mg, 0.763 mmol) in anhydrous DMF (4 mL) was treated with PyBOP (790 mg, 1.52 mmol), NMM (0.33 mL, 3.05 mmol) and (E)-ethyl 3-(3-aminophenyl)acrylate (33b, 175 mg, 0.92 mmol) to give ethyl ester 37b as a pale solid (210 mg, 65%). mp = 185.7-187.1 ⁰C. ¹H NMR (DMSO-d₆, 600 MHz): δ 10.98 (s, IH), 10.91 (s, IH), 8.38 (s, IH), 8.10 (s, IH), 7.92 (d, J = 6.7 Hz, IH), 7.81 (s, IH), 7.68 (d, J= 7.9 Hz, IH), 7.66 (d, J= 7.6 Hz, IH), 7.59 (d, 7=16.1 Hz, IH), 7.51 (d, J= 7.1 Hz, IH), 7.47 (s, IH), 6.53 (d, J= 15.8 Hz, IH), 4.17 (q, J= 6.7 Hz, 2H), 3.91 (s, 3H), 1.24 (t, J= 6.3 Hz, 3H). ¹³C NMR (DMSO-d₆, 150 MHz): δ 166.8, 165.3, 156.6, 153.1, 150.3, 148.2, 144.7, 141.5, 140.3, 135.3, 129.7, 126.3, 123.5, 122.5, 120.9, 118.6, 118.1, 110.9, 110.8, 101.8, 60.5, 55.3, 13.9. HRMS calcd for C₂₃H₂₂N₃O₆ 436.1433 (M + H)⁺, found 436.1439.

Preparation of Carboxylic acid 38a. To a suspension of ethyl ester 37a (450 mg, 1.03 mmol) in THF (18 mL) was added methanol (6mL) and NaOH (910 mg in 18 mL water). The mixture was stirred at room temperature overnight. Solvents were removed and the residue was diluted with water and IN HCl was added until pH ~ 1-2. The solid that formed was collected by filtration and dried to carboxylic acid 38a as a white solid (260 mg, 62%). mp = 184.2-185.7 ⁰C. ¹H NMR (DMSO-d₆, 600 MHz): δ 12.07 (brs, IH), 10.85 (s, IH), 10.82 (s, IH), 8.37 (s, IH), 7.81 (d, J= 8.2 Hz, IH), 7.66 (d, J= 4.4 Hz, 2H), 7.64 (s, IH), 7.62 (d, J= 8.4 Hz, 2H), 7.54 (d, J= 8.5 Hz, IH ), 7.51 (d, J= 15.8 Hz, IH), 7.45 (s, IH), 6.44 (d, J= 16.1 Hz, IH), 3.91 (s, 3H). HRMS calcd for C₂IH₁₈N₃O₆ 408.1233 (M + H)⁺, found 408.1236.

Preparation! of Carboxylic acid 38b. Following procedures similar to those described for carboxylic acid 38a, ethyl ester 37b (210 mg, 0.48 mmol) in THF (6 mL) was treated with methanol (3mL) and NaOH (0.29 g in 6 mL water) to give carboxylic acid 38b as a light yellow solid (150 mg, 77%). rnp = 188.5-189.3 ⁰C. ¹H NMR (DMSO-d₆, 600 MHz): δ YlAA (brs, IH), 10.99 (s, IH), 10.91 (s, IH), 8.37 (s, IH), 8.09 (s, IH), 7.89 (d, J= 7.9 Hz, IH), 7.81 (s, IH), 7.67 (d, J= 7.9 Hz, 2H), 7.65 (d, J= 7.6 Hz, IH), 7.53 (d, J= 16.4 Hz, IH), 7.47 (s, IH), 7.42 (d, J= 7.3 Hz, IH), 6.43 (d, J= 15.8 Hz, IH), 3.95 (s, 3H). ¹³C NMR (DMSO-d₆, 150 MHz): £ 166.9, 165.2, 155.3, 152.2, 149.7, 146.8, 143.5, 141.0, 139.8, 134.2, 128.9, 125.4, 122.7, 121.3, 1 19.4, 118.7, 116.6, 109.6, 109.3, 100.4, 54.9. HRMS calcd for C₂iH₁₈N₃O₆ 408.1051 (M + H)⁺, found 408.1053.

Preparation of Protected hydroxamate 39a. A solution of carboxylic acid 38a (250 mg, 0.61 mmol), 0-tritylhydroxylamine (277 mg, 1.22 mmol), EDC (295 mg, 1.53 mmol), and HOBt (166 mg, 1.22 mmol) in anhydrous DMF (20 mL) was stirred at rt for 24 h. After concentration, the residue was diluted with EtOAc (25 mL) and washed with water (2x15 mL) and brine (2x20 mL). The organic layer was dried over Na₂SO₄ and filtered. The filtrate was concentrated and the residue was purified by flash column chromatography (0-5% MeOH/CH₂Cl₂) to give protected hydroxamate 39a as a white solid (210 mg, 52%). mp = 209.5-211.1 ⁰C. ¹H NMR (DMSO-d₆, 600 MHz): δ 11.09 (s, IH), 1 1.05 (s, IH), 10.61 (s, IH), 8.38 (s, IH), 7.82 (s, IH), 7.67 (s, IH), 7.66 (d, J= 8.4 Hz, 2H), 7.64 (s, IH), 7.61 (d, J= 7.1 Hz, 2H), 7.48 (s, IH), 7.43 (d, J= 15.7 Hz, IH), 7.38-7.23 (m, 15H), 6,44 (d, J= 15.5 Hz, IH), 3.95 (s, 3H). HRMS calcd for C₄₀H₃₃N₄O₆ 665.2642 (M + H)⁺, found 665.2649.

Preparation of Protected hydroxamate 39b. Following procedures similar to those described for protected hydroxamate 39a, carboxylic acid 38b (120 mg, 0.29 mmol) in anhydrous DMF (10 mL) was treated with H₂N-OTr (135 mg, 0.59 mmol), EDC (142 mg, 0.73 mmol), and HOBt (80 mg, 0.59 mmol) to give protected hydroxamate 39b as a white solid (70 mg, 55%). mp = 218.5-219.2 ⁰C. ¹H NMR (DMSO-d₆, 600 MHz): δ 10.94 (s, IH), 10.89 (s, IH), 10.46 (s, IH), 8.36 (s, IH), 7.98 (s, IH), 7.92 (s, IH), 7.79-7.77 (m, 2H), 7.67 (d, J= 8.5 Hz, IH), 7.62 (d, J= 8.8 Hz, IH), 7.48 (s, IH), 7.41 (d. J= 16.4 Hz, IH), 7.39-7.18 (m, 15H), 6.44 (d, J= 15.5 Hz, IH), 3.91 (s, 3H). HRMS calcd for C₄₀H₃₃N₄O₆ 665.2332 (M + H)⁺, found 665.2337.

Preparation of Hydroxamic acid 19a. To a solution of protected hydroxamate 39a (70 mg, 0.10 mmol) in anhydrous CH₂Cl₂ (6 mL) was added TFA (0.15 mL). The resulting yellow solution was treated with Et₃SiH till it was colorless. After being stirring for an additional 30 min, the solid formed was filtered, washed with anhydrous CH₂Cl₂ and dried under high vacuum to give hydroxamic acid 19a as a light yellow solid (9.3 mg, 22%). mp = 174.3-175.9 ⁰C. ¹H NMR (DMSO-d₆, 600 MHz): 511.01 (s, IH), 10.96 (s, IH), 10.83 (s, IH), 8.39 (s, IH), 8.05 (s, IH), 7.87 (d, J= 7.9 Hz, IH), 7.83 (s, IH), 7.65 (d, J= 8.5 Hz, 2H), 7.62 (d, J= 8.2 Hz, 2H), 7.49 (s,lH), 7.43 (d, J= 15.7 Hz, IH), 7.37 (d, J= 7.7 Hz, IH), 6.39 (d, J= 15.9 Hz, IH), 3.92 (s, 3H). HRMS calcd for C₂IHi₉N₄O₆ 423.1292 (M + H)⁺, found 423.1310.

Preparationi of Hydroxamic acid 19b. Following procedures similar to those described for hydroxamic acid 19a, protected hydroxamate 39b (50 mg, 0.075 mmol) in anhydrous CH₂Cl₂ (6 mL) was treated with TFA (0.1 mL) to give hydroxamic acid 19b as a white solid (7.5 mg, 25%). mp = 173.5-174.8 ⁰C. ¹H NMR (DMSO-d₆, 600 MHz): δ 11.04 (s, IH), 10.97 (s, IH), 10.83 (s,

IH), 8.39 (s, IH), 8.05 (s, IH), 7.84 (d, J= 7.9 Hz, IH), 7.81 (s, IH), 7.67 (d, J= 8.5 Hz, IH), 7.65 (d, J= 8.5 Hz, IH), 7.48 (s, IH), 7.43 (s, IH), 7.41 (d, J= 15.5 Hz, IH), 7.34 (d, J= 7.6 Hz, IH), 6.41 (d, J= 15.8 Hz, IH), 3.92 (s, 3H), 1.21 (s, IH). HRMS calcd for C₂iH₁₉N₄O₆ 423.1642 (M + H)⁺, found 423.1645.

BIOLOGICAL ASSAYS

IMPDH Inhibition assays were performed as previously described (Umejiego, N. N. et al., J Biol Chem 2004, 279, 40320-40327). Briefly, assays were set up in duplicate using two different concentrations of IMPDH type 1 (87 and 155 nM) and type 2 (33 and 66 nM) and varying concentrations of inhibitor. IMPDH and inhibitors were added to 100 μl reaction buffer (50 mM Tris, pH 8.0, 100 mM KCL, 1 mM DTT, 100 μM IMP, 100 μM NAD) at 25 degrees C, mixed gently and the production of NADH was monitored by following changes in absorbance at 340 nm on a Molecular Devices M5e multimode plate reader. Steady state velocities were used to determine IC50 and K,^App values by fitting the velocities vs. inhibitor concentration to the sigmoidal concentration-response curve (variable slope) and the Morrison equation respectively using

GraphPad Prism (Morrison, J. F. Biochim Biophys Acta 1969, 185, 269-286). HDAC inhibition assays were performed using the HDAC Activity/Inhibitor Screening Assay Kit (Cayman Chemical) per the manufacturers instructions. Inhibitors were suspended in either DMSO or Methanol. End point readings were used to determine IC_5O values by fitting the fractional fluorescence vs. inhibitor concentration to the sigmoidal concentration-response curve (variable slope) using GraphPad Prism. Curves were corrected for Auto-fluorescence by making a standard concentration curve, substituting compound for solvent using the background well conditions.

Inhibition of proliferation of K562 cells. About 2000 cells/well of logarithmically growing human myelogenous leukemia K562 cells were plated into 96-well plates and incubated at 37 °C for 24 hours. Compounds at final concentrations up to 100 μM were added in duplicate wells in 0.15% DMSO (final concentration), mixed and incubated for 72 hours. At the end of the incubation period 20 μl of MTS reagent was added, mixed and further incubated for 3 hours and then absorbance read at 490 nm in a plate reader. Control cells exhibited 3-doublings (doubling time was 24 hours).

Inhibition of proliferation of K562 cells resistant to tiazofurin. This assay is performed in a similar manner to that described above.

Inhibition of proliferation of K562 cells resistant to Gleevec. This assay is performed in a similar manner to that described above.

Differentiation of K562 cells. Logarithmically growing K562 cells (1.0 x 10³ cells/0.1 ml) were plated in triplicate into 96-well plates in RPMI 1640 medium containing 10% heat-inactivated fetal bovine serum and antibiotics and incubated at 37 ⁰C in an atmosphere of air and 5% CO₂. Twenty-four hours later compounds were added and further incubated for 5 days. For examining effect of compounds on cytotoxicity, 20 μl of MTS reagent was added and further incubated for 3 hours and the absorbance was read at 490 nm. For examining effect on cellular differentiation, 25 μl of 5-day incubated cell suspension was taken and mixed with 25 μl of differentiation reagent (0.2% benzidine in acetic acid 0.15% H₂O₂) and counted about 500 cells to determine the percent of differentiated cells.

Evaluation of the therapeutic potential of IMPDH/HDAC inhibitors in xenograft mouse model for CML. The therapeutic potential of IMPDH/HDAC inhibitors can be determined as described by Patterson at al., Developments in Nucleic Acids, IHL Press, 2004, see ref. 44). Evaluation of the therapeutic potential of IMPDH/HDAC inhibitors in mouse model for CML.

The expression of BCR-ABL in mouse bone marrow cells efficiently (100%) and rapidly (in 3-4 weeks) induces a myeloproliferative disease (MPD) closely resembling the human CML in chronic phase. Common features of the disease include high peripheral blood counts (typically several hundred thousand per microliter) with granulocyte predominance, splenomegaly, extramedullary hematopoiesis in liver and pulmonary hemorrhages owing to extensive granulocyte infiltration in the lung. This model was used extensively in studies of the role of domains and downstream signaling pathways of BCR/ABL.

It is interesting that the mycophenolic adenine dinucleotide (C2-MAD) has anti-CML activity in SCID mice xenotransplanted with K562 cells. However, K562 is a human CML blast phase cell line. The therapeutic potential of IMPDH inhibitors should also be tested in primary tumor cells. Development of CML is a complex process that involves not only the effects of BCR/ABL, but also the context of its host cells and the rest of the in vivo environment. The therapeutic potential of IMPDH inhibitors in treating BCR/ABL induced CML-like disease can be examined using the mouse bone marrow transduction and transplantation (BMT) model for CML. Briefly, BCR/ABL and vector control retroviruses are generated by transiently transfecting BCR- ABL retroviral DNA or vector control into BOSC23 retroviral packaging cell line as described. Freshly isolated mouse bone marrow cells from 5-fluorouracil (5-FU) treated Balb/C mice is transduced with the above retroviruses. The purpose of 5-FU treatment is to eliminate the proliferating hematopoietic precursor cells and to enrich and stimulate hematopoietic stem cells

(HSCs). The infected bone marrow cells are transplanted into lethally irradiated syngeneic recipient mice. One week after bone marrow transplantation, the recipient mice are treated with selected IMPDH inhibitors as described earlier. As described earlier, the toxicity of the candidate inhibitors (LDi₀) will be determined prior to the treatment. 10-20% of LDio dose is typically used for the treatment. The diseases are examined following the guidelines recommended by the hematopathology subcommittee of the Mouse Models of Human Cancers Consortium. Generally, beginning at 2 weeks after bone marrow transplantation, mice are monitored with peripheral WBC counts and blood smears using blood from tail bleeds. Immunophenotyping and histopathological analyses of affected tissues or tumor cells can be performed as previously described.

Data for representative compounds of the invention is shown in the following table.

Biological evaluations of dual inhibitors of IMPDH and HDAC

HDAC nuclear K562 cell

IMPDHl K₁ IMPDH2 K₁

Compound extract IC₅O proliferation IC₅₀

(μM) (μM) (μM) (μM)

16a 7.8 ± 0.8 1.2 ± 0.2 0.026 ± 0.006 3.5

16b 2.3 ± 0.1 0.34 ± 0.06 0.83 ± 0.39 18

16c > 100 11 ± 1 0.036 ± 0.020 ND^a

16d 44 ± 18 2.6 ± 0.3 0.64 ± 0.56 28

17a 17 ± 10 1.4 ± 0.6 0.23 ± 0.10 5.3

17b 4.4 ± 0.5 1.5 ± 0.1 0.89 ± 0.28 > 100

18a 0.30 ± 0.05 0.25 ± 0.12 0.55 ± 0.14 4.9

18b 0.58 ± 0.06 0.12 ± 0.01 3.0 ± 0.7 > 100

18c 1.2 ± 0.3 0.23 ± 0.10 0.63 ± 0.46 4.0

18d 8.2 1.2 3.4 ± 0.7 38

19a 7.1 ± 0.6 1.8 ± 0.3 17 ± 12 72

19b 0.46 ± 0.03 0.20 ± 0.02 1.8 ± 0.5 28

119 5.0 1.7 0.06 0.29

122 2.8 0.44 0.09 >100 3NO, not determined.

Compound 119 was evaluated against a panel of NCI cancer cell lines. Results are shown in the table below (IC₅O, last column). A low micromolar activity was found against the majority of cell lines tested. Only 6 cell lines out of 55 did not respond. Sub-micromolar activity was found against Leukemia - all major types of leukemia (four out of five cell lines); colon cancer - two out of four cell lines; melanoma - two out of eight cell lines; and breast cancer - two out of seven cell lines

Leukemia CCRF-CEM 7 3 6.66 0.22 uM

Leukemia HL-60(TB) 7 8 6.32 0.49 uM

Leukemia K-562 7 5 6.46 0.35 uM

Leukemia MOLT-4 7 6 6.37 0.23 uM

Leukemia RPMI-8226 7 10 5.49 3.23 uM

Non-Small Cell

Lung Cancer A549/ATCC 1 4 5.3 5.01 uM

Non-Small Cell

Lung Cancer EKVX 1 8 5.03 9.33 uM

Non-Small Cell

Lung Cancer HOP-62 1 26 4 10O uM

Non-Small Cell

Lung Cancer HOP-92 1 29 4 10O uM

Non-Small Cell

Lung Cancer NCI-H226 1 13 4.7 20.0 uM

Non-Small Cell

Lung Cancer NCI-H23 1 1 5.08 8.3 uM

Non-Small Cell

Lung Cancer NCI-H322M 1 17 5.18 6.6 uM

Non-Small Cell

Lung Cancer NCI-H460 1 21 5.56 2.75 uM

Non-Small Cell

Lung Cancer NCI-H522 1 3 4.66 21.9 uM

Colon Cancer COLO 205 4 10 6.14 0.72 uM

Colon Cancer HCT-116 4 3 6.36 0.44 uM

Colon Cancer HCT-15 4 15 4.83 14.8 uM

Colon Cancer KM12 4 17 5.39 4.07 uM

Colon Cancer SW-620 4 9 6.25 0.56 uM

CNS Cancer SF-268 12 14 5.22 6.02 uM

CNS Cancer SF-295 12 15 5.36 4.36 uM

CNS Cancer SF-539 12 16 5.27 5.37 uM

CNS Cancer SNB-19 12 2 5.41 3.90 uM

CNS Cancer SNB-75 12 5 4 10O uM

CNS Cancer U251 12 9 5.92 1.2O uM

Melanoma LOX IMVI 10 1 5.95 1.12 uM

Melanoma MALME-3M 10 2 4 10O uM

Melanoma M14 10 14 5.34 4.5 uM

Melanoma SK-MEL-2 10 5 4 10O uM

Melanoma SK-MEL-28 10 8 4.95 11.2 uM

Melanoma SK-MEL-5 10 7 6.23 0.59 uM

Melanoma UACC-257 10 21 4.99 1O uM

Melanoma UACC-62 10 20 6.11 0.77 uM

Ovarian Cancer IGROV1 6 10 5.31 4.90 uM

Ovarian Cancer OVCAR-4 6 2 5.27 5.3 uM

Ovarian Cancer OVCAR-5 6 3 5.27 5.3 uM Ovarian Cancer OVCAR-8 6 5 5.48 3.31 u M

Ovarian Cancer SK-OV-3 6 11 5.47 3.39 uM

Renal Cancer 786-0 9 18 5.25 5.62 uM

Renal Cancer A498 9 13 5.47 3.39 uM

Renal Cancer ACHN 9 23 5.47 3.39 uM

Renal Cancer CAKI-1 9 15 5.39 4.07 uM

Renal Cancer RXF 393 9 16 5.33 4.67 uM

Renal Cancer SN12C 9 8 5.49 3.23 uM

Renal Cancer TK-10 9 24 5.44 3.63 uM

Renal Cancer UO-31 9 4 5.2 6.31 uM

Prostate Cancer PC-3 11 1 5.39 4.07 uM

Prostate Cancer DU-145 11 3 5.58 2.63 uM

Breast Cancer MCF7 5 1 6.09 0.81 uM

NCI/ADR-

Breast Cancer RES 5 2 5.08 8.32 uM

MDA-MB-

Breast Cancer 231 /ATCC 5 5 5.33 4.68 uM

MDA-MB-

Breast Cancer 435 5 11 6.1 0.79 uM

Breast Cancer BT-549 5 13 4 100 uM

Breast Cancer T-47D 5 14 6.06 0.87 uM

MDA-MB-

Breast Cancer 468 5 18 5.71 1.95 uM

The growth inhibitory activity of Compound 119 was compared to that of Gleevec and mycophenolic acid (MPA) in certain NCI cell lines. In general the profiles were similar. Selective results are shown below.

Compounds of the invention include compounds that are useful for treatment of chronic myelogenous leukemia (CML) resistant to gleevec (imanitib), a first line targeted therapy drug that inhibits the bcr-abl tyrosine kinase specific for CML. Representative compounds of the invention also show a potent anti-leukemic activity in cells resistant to tiazofurin, an inhibitor of IMP- dehydrogenase, approved for the treatment of patients in blast crisis (BC) of CML.

Numerous second generation inhibitors of the Bcr-Abl tyrosine kinase are in clinical trials (such as nilotinib, Novartis; dasatinib, BMS; and others, see Jorgensen, H. G., et al., Blood 2001, 109, 4016-4019; Copland, M., et al., ; Blood2006, 107, 4532-4539; and Jorgensen, H. G., et al., Leukemia 2005, 19, 1184-1191). Few of them are active against all mutants in gleevec-resistant leukemia. Since compounds of the present invention in certain embodiments do not target the Bcr- AbI tyrosine kinase they are expected to show a potent anti-leukemic activity in cells resistant to gleevec and to the second generation drugs.

A unique ability of compounds of certain embodiments of the present invention to differentiate more than 80% of K562 leukemic cells at a low nanomolar concentration indicates a great therapeutic potential. Not only do these compounds convert leukemic cells into non- proliferating, mature cells (able to produce hemoglobin), but they also affect (differentiate) leukemic stem cells, which do not respond to known therapeutic agents. However, when differentiated, cancer stem cells and/or cancer cells described as tumor-propagating cells, become susceptible to drugs including compounds of this invention. At the same low nanomolar concentration the compounds of certain embodiments of the present invention inhibit 100% of proliferation of K562 leukemic cells. The remaining undifferentiated cells may have underwent apoptosis. Differentiation or apoptotic pathway can be triggered by the same compounds depending on concentration of the compounds and not well defined cellular factors (see Jacquel, A., et al., Oncogene 2006, 25, 781-794; and Jacquel, A., et al., Oncogene 2007, 26, 2445-2458).

Due to a unique ability of dual inhibitors of certain embodiments of the present invention to differentiate cancer cells, such as converting CML cells into non-proliferating cells able to produce hemoglobin, their therapeutic potential is of great interest and extends well beyond CML. In addition, the differentiating activities of dual inhibitors are expected to affect cancer stem cells, especially C ML stem cells, which do not respond to known therapeutic agents (see Graham, S. M., et al., BloodlOOl, 99, 319-325; Goodsell, D. S., Stem Cells 2003, 21, 620-621; Scadden, D. T., Best Pract Res Clin Haematol 2007, 20, 19-27; Jordan, C. T., Best Pract Res Clin Haematol 2007, 20, 13-18; Yang, Z. J., Wechsler-Reya, Cancer Cell 2007, 11, 3-5; and Everts, S., Chemical & Engineering News 2007, 85, 28-29). However, when differentiated into regular cancer cells, they become susceptible to available drugs including compounds of the present invention. Thus, a combination of dual inhibitory activity (HDAC/IMPDH) with a cancer cell differentiation/apoptotic potential offers a new opportunity for successful treatment of not only leukemic malignances but also cancers such as prostate and colon where, e.g., all three components (HDAC, IMPDH, and differentiation/apoptosis) play an important role in controlling the progress of such diseases. Eradication of cancer stem cells is a new goal of modern cancer chemotherapy

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to") unless otherwise noted. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

All publications, patents and patent applications cited herein are incorporated herein by reference.

Claims

WHAT IS CLAIMED IS:

1. A compound of formula I:

A -X - L - B

wherein:

A is:

X is a direct bond, -NH-, -NH-C(O)-, -NH-C(O)-NH-, or -NH-C(O)-C(O)-NH;

L is a saturated or unsaturated, branched or unbranched, Ci-Ci₅ hydrocarbon chain that is optionally substituted on carbon with one or more oxo (=0), wherein one or more carbon atoms of the chain can optionally be replaced with O, S, NH, SO2, a divalent aryl, or a divalent heteroaryl group;

B is:

n is 1, 2, 3, 4, 5, or 6; or a salt thereof.

2. The compound of claim 1 wherein A is:

3. The compound of claim 1 or 2 wherein X is -NH-C(=0)-, -NH-C(O)-NH-, or -NH-C(O)-C(O)-NH.

4. The compound of any one of claims 1-3 wherein B is

5. The compound of any one of claims 1-3 wherein B is

O

H

6. The compound of any one of claims 1-5, wherein L is a saturated or unsaturated, branched or unbranched, C₁-C₁₀ hydrocarbon.

7. The compound of any one of claims 1-5, wherein L is a saturated or unsaturated, branched or unbranched, Ci-C₅ hydrocarbon.

8. The compound of claim 6, wherein L is a saturated or unsaturated, branched or unbranched, C₄-C₇ hydrocarbon.

9. The compound of any one of claims 1 -5 wherein L is,

10. The compound of claim 1 which is compound 16a, 16b, 16c, 16d, 17a, 17b, 18a, 18b, 18c, 18d, 19a, 19b, 119, or 122, or a pharmaceutically acceptable salt thereof.

11. The compound of claim 1, which is:

or a pharmaceutically acceptable salt thereof.

12. A pharmaceutical composition comprising a compound of formula I as described in any one of claims 1-11, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

13. A method for treating cancer in a patient, comprising administering an effective amount of a a compound of formula I as described in any one of claims 1- 11, or a pharmaceutically acceptable salt thereof, to the patient.

14. The method of claim 13, wherein the cancer is leukemia.

15. The method of claim 13, wherein the cancer is chronic myelogenous leukemia.

16. The method of claim 13, wherein the cancer is prostate or colon cancer.

17. The method of any one of claims 13-16 wherein the treatment destroys cancer stem cells.

18. The method of claim 13, wherein the cancer is a solid cancer.

19. A compound of formula I as described in any one of claims 1-11, or a pharmaceutically acceptable salt thereof, for use in medical treatment or diagnosis.

20. The use of a compound of formula I as described in any one of claims 1-11, or a pharmaceutically acceptable salt thereof, to prepare a medicament useful for treating cancer in an animal.

21. A compound of formula I as described in any one of claims 1 - 11 , or a pharmaceutically acceptable salt thereof, for the prophylactic or therapeutic treaitment of cancer.