WO2011009695A1

WO2011009695A1 - New anti-angiogenic compounds

Info

Publication number: WO2011009695A1
Application number: PCT/EP2010/059151
Authority: WO
Inventors: Karine Lafleur; Danzhi Huang; Cristina Nevado; Amedeo Caflisch
Original assignee: Universität Zürich
Priority date: 2009-07-21
Filing date: 2010-06-28
Publication date: 2011-01-27

Abstract

The invention relates to compounds of formula (I), tautomers and salts thereof wherein R¹ is methyl or ethyl, R² is n-butyl or o-methoxyphenyl, R³ is hydrogen or hydroxy; and R⁴ is hydrogen or methyl. These compounds are receptor tyrosine kinase EphB4 inhibitors useful for the treatment of angiogenesis dependent cancers and intraocular neovascular syndromes.

Description

IMIDAZO [2 , 1-F] PURINE DERIVATIVES USEFUL AS ANTIANGIOGENIC EPHB4 INHIBITORS

Field of the invention

5 The invention relates to compounds and pharmaceutical preparations useful in the

treatment of angiogenesis dependent cancers and intraocular neovascular syndromes.

Background of the invention

10 The receptor tyrosine kinase EphB4 is a highly attractive angiogenic target involved in many types of cancer (Cheng N., Brantley D. M. and Chen J., Cytokine Growth Factor Rev 2002, 13:75-85). Angiogenesis, the formation of new blood vessels from pre-existing vasculature, is a multi-step process involving many various factors, which stimulate endothelial cell proliferation, migration, and assembly, as well as recruitment of

15 perivascular cells and extracellular matrix remodelling. Angiogenesis is implicated in the pathogenesis of a variety of disorders, including solid tumours, intraocular neovascular syndromes such as proliferative retinopathies or age-related macular degeneration (AMD), rheumatoid arthritis, and psoriasis.

20 Ephrins and their receptors were first identified in studies for neuronal growth during

development. Unlike other families of receptor tyrosine kinases, which bind soluble ligands, ephrin receptors interact with cell surface-bound ephrin ligands . Ephrins attach to the cell membrane either through a glycosylphosphatidyl inositol anchor (ephrin A) or a transmembrane domain (ephrin B). Ephrin receptors are likewise divided in two

25 subclasses EphA and EphB, depending on the type of interaction with their ligands ephrin A or B. Ephrins and their receptors have been shown to play an essential role in vascular development during embryogenesis and in adult angiogenesis, as key regulators of vascular assembly, arteriovenous differentiation, and boundary formation. Both EphA and EphB receptors and their ligands are involved in vascular development. Especially, ephrin

30 B2 is expressed in arterial endothelial cells, whereas its cognate receptor, EphB4 is

expressed in venous endothelial cells. EphB4 (also named HTK) and its ligand, ephrin B2 (HTKL), play important roles in establishing and determining vascular networks. Blocking this receptor/ligand pair inhibits the end stage of tumour blood vessel formation, as well as causes direct growth inhibition of certain cancers.

35 EphB4 seems to be rather recalcitrant to inhibition because, despite its potential therapeutic importance, only two series of non-peptidic small molecule inhibitors have been reported in the literature up to date (Miyazaki Y. et al., Bioorg Med Chem Lett 2007, 17:250-254). Examples of angiogenesis inhibitors are found in WO 2006/131003 and WO 2007/062805.

Based on computational methods, compound classes were identified, which should exhibit substantial EphB4 inhibition properties. The prediction was verified in practice, and a number of substituted 7-phenyl-1 H-imidazo[2,1-f]purine-2,4(3H,8H)-diones were described and shown to have the expected inhibitory properties (PCT/EP2009/000439).

Summary of the invention

The invention relates to compounds of the formula (I)

wherein

R¹ is methyl or ethyl;

R² is n-butyl or o-methoxyphenyl;

R³ is hydrogen or hydroxy; and

R⁴ is hydrogen or methyl;

with the proviso that, if R¹ is methyl, at least one of R³ and R⁴ is different from hydrogen;

and tautomers and salts thereof.

Furthermore the invention relates to pharmaceutical preparations comprising the compounds mentioned hereinbefore, use of such compounds or pharmaceutical preparations comprising these in the treatment of angiogenesis dependent cancers and intraocular neovascular syndromes, and methods of treatment of angiogenesis dependent cancers and intraocular neovascular syndromes. Detailed description of the invention

The invention relates to compounds of formula (I)

wherein

R¹ is methyl or ethyl;

R² is n-butyl or o-methoxyphenyl;

R³ is hydrogen or hydroxy; and

R⁴ is hydrogen or methyl;

and tautomers and salts thereof. In formula (I) the bond connecting substituent R³ and R⁴, respectively, with the phenyl group is not connected with a particular carbon atom of the phenyl ring. The meaning of such a formula is that substituent R³ and R⁴, respectively, can be connected to the ortho, meta or para position of the phenyl ring, independently of each other. This means that substituents R³ and R⁴ may be located in ortho/ortho, ortho/meta, ortho/para, meta/ortho, meta/meta, meta/para, para/ortho or para/meta position, preferably in ortho/meta, ortho/para, meta/ortho, or para/ortho position. If R⁴ is hydrogen, R³ is in ortho, meta or para position, preferably in meta or para position. If R³ is hydrogen, R⁴ is in ortho, meta or para position, preferably in ortho position. Tautomers are especially tautomers of the basic xanthine nucleus, wherein the proton on the ring nitrogen moves to either of the carbonyl groups and the corresponding carbonyl group double bond is shifted into the ring, representing a so-called lactam-lactim tautomerism. Valence tautomers of the phenyl group, wherein double bonds are formally shifted to the single bond positions and vice versa, are also included in the definition of tautomers as herein understood. Salts are especially the pharmaceutically acceptable salts of compounds of formula (I).

Such salts are formed, for example, as acid addition salts, preferably with organic or inorganic acids, from compounds of formula (I) with a basic nitrogen atom, especially the pharmaceutically acceptable salts. Suitable inorganic acids are, for example, halogen acids, such as hydrochloric acid, sulfuric acid, or phosphoric acid. Suitable organic acids are, for example, carboxylic, phosphonic, sulfonic or sulfamic acids, for example acetic acid, glycolic acid, lactic acid, malic acid, tartaric acid, or citric acid. Salts are also formed, for example, as salts with organic or inorganic bases, from compounds of formula (I) with a nitrogen atom bearing an acidic hydrogen. Examples of suitable cations are sodium, potassium, calcium or magnesium cations, or cations of organic nitrogen bases, e.g. protonated mono-, di- or tri-(2-hydroxethyl)amine. In view of the close relationship between the novel compounds in free form and those in the form of their salts, any reference to the free compounds hereinbefore and hereinafter is to be understood as referring also to the corresponding salts, as appropriate and expedient. Likewise, in view of the close relationship between the novel compounds as shown in formula (I) and their tautomers, any reference to the compounds of formula (I) is to be understood as referring also to the corresponding tautomers.

The compounds of formula (I) have valuable pharmacological properties. The invention also relates to compounds of formula (I) as defined hereinbefore for use as medicaments. Compounds of the formula (I) inhibit Ephrin receptor kinase, in particular EphB4 kinase, are modulating angiogenesis, and are especially appropriate for the use against diseases or disorders such as angiogenesis dependent cancers, intraocular neovascular syndromes and related diseases, e.g. psoriasis and rheumathoid arthritis. Angiogenesis dependent cancers are, for example, so-called solid tumors, especially cancers of the gastrointestinal tract, the pancreas, breast, stomach, cervix, bladder, kidney, prostate, ovaries, endometrium, lung, brain, melanoma, Kaposi's sarcoma, squamous cell carcinoma of head and neck, malignant pleural mesotheriorna, lymphoma or multiple myeloma, also haemangioblastoma and haemangioma, and further liquid tumors, e.g. leukemias. Intraocular neovascular syndromes are e.g. diabetic retinopathy, neovascular glaucoma, ischemic retinopathies and macula degeneration, e.g. age related macula degeneration. Other angiogenesis related diseases are restenosis, e.g. stent-induced restenosis, Crohn' s disease, and Hodgkin's disease. In particular the invention relates to compounds of formula (I), wherein

R¹ is methyl;

R² is n-butyl or o-methoxyphenyl;

R³ is hydrogen, m-hydroxy or p-hydroxy; and

R⁴ is hydrogen or o-methyl;

with the proviso that at least one of R³ and R⁴ is different from hydrogen;

and tautomers and salts thereof. Likewise the invention relates to the compound of formula (I), wherein

R¹ is ethyl;

R² is n-butyl; and

R³ and R⁴ are hydrogen;

and tautomers and salts thereof.

Preferably the invention relates to compounds of formula (I), wherein

R¹ is methyl;

R² is n-butyl;

R³ is m-hydroxy or p-hydroxy; and

R⁴ is hydrogen;

and tautomers and salts thereof.

Likewise the invention relates to compounds of formula (I), wherein

R¹ is methyl;

R² is o-methoxyphenyl;

R³ is hydrogen, m-hydroxy or p-hydroxy; and

R⁴ is hydrogen or o-methyl;

with the proviso that at least one of R³ and R⁴ is different from hydrogen;

and tautomers and salts thereof.

Most preferred are the compounds of formula (I),

wherein R¹ is methyl, R² is o-methoxyphenyl, R³ is hydrogen, and R⁴ is o-methyl; or wherein R¹ is methyl, R² is o-methoxyphenyl, R³ is m-hydroxy, and R⁴ is hydrogen; or wherein R¹ is methyl, R² is n-butyl, R³ is m-hydroxy, and R⁴ is hydrogen; or wherein R¹ is methyl, R² is n-butyl, R³ is p-hydroxy, and R⁴ is hydrogen; or wherein R¹ is methyl, R² is o-methoxyphenyl, R³ is p-hydroxy, and R⁴ is o-methyl; or wherein R¹ is methyl, R² is o-methoxyphenyl, R³ is m-hydroxy, and R⁴ is o-methyl; or wherein R¹ is ethyl, R² is n-butyl, and R³ and R⁴ are hydrogen; and

and tautomers and salts thereof. Particularly preferred are the compounds of the examples.

More particularly, the invention relates to compounds of formula (I), wherein

R¹ is methyl or ethyl;

R² is n-butyl or o-methoxyphenyl;

R³ is hydrogen or hydroxy; and

R⁴ is hydrogen or methyl;

and tautomers and salts thereof

for use in the treatment of angiogenesis dependent cancers and intraocular neovascular syndromes.

Most preferred, the invention relates to the compounds of the examples for use in the treatment of angiogenesis dependent cancers and intraocular neovascular syndromes.

Furthermore the invention relates to pharmaceutical preparations comprising the compounds mentioned hereinbefore as active ingredient and that can be used especially in the treatment of the diseases mentioned. Compositions for enteral administration, such as nasal, buccal, rectal or, especially, oral administration, and for parenteral

administration, such as intravenous, intramuscular or subcutaneous administration, to warm-blooded animals, especially humans, are especially preferred. The compositions comprise the active ingredient alone or, preferably, together with a pharmaceutically acceptable carrier. The dosage of the active ingredient depends upon the disease to be treated and upon the species, its age, weight, and individual condition, the individual pharmacokinetic data, and the mode of administration.

The present invention relates especially to pharmaceutical compositions that comprise a compound of formula (I), a tautomer, or a pharmaceutically acceptable salt, or a hydrate or solvate thereof, and at least one pharmaceutically acceptable carrier. A pharmaceutical composition for the treatment of angiogenesis dependent cancers and intraocular neovascular syndromes of a warm-blooded animal, especially a human requiring such treatment, comprising a compound of formula (I) as active ingredient in a quantity that is therapeutically active against the said diseases, is likewise preferred.

The pharmaceutical compositions comprise from approximately 1 % to approximately 95% active ingredient. Unit dose forms are, for example, coated and uncoated tablets, ampoules, vials, suppositories, or capsules. Further dosage forms are, for example, ointments, creams, pastes, foams, tinctures, lip-sticks, drops, sprays, dispersions, etc. Examples are capsules containing from about 0.05 g to about 1.0 g active ingredient.

The pharmaceutical compositions of the present invention are prepared in a manner known per se, for example by means of conventional mixing, granulating, coating, dissolving or lyophilizing processes.

Preference is given to the use of solutions of the active ingredient, and also suspensions or dispersions, especially isotonic aqueous solutions, dispersions or suspensions which, for example in the case of lyophilized compositions comprising the active ingredient alone or together with a carrier, for example mannitol, can be made up before use. The pharmaceutical compositions may be sterilized and/or may comprise excipients, for example preservatives, stabilizers, wetting agents and/or emulsifiers, solubilizers, salts for regulating osmotic pressure and/or buffers and are prepared in a manner known per se, for example by means of conventional dissolving and lyophilizing processes. The said solutions or suspensions may comprise viscosity-increasing agents, typically sodium carboxymethylcellulose, carboxymethylcellulose, dextran, polyvinylpyrrolidone, or gelatins, or also solubilizers, e.g. Tween 80® (polyoxyethylene(20)sorbitan mono-oleate).

Suspensions in oil comprise as the oil component the vegetable, synthetic, or semisynthetic oils customary for injection purposes. In respect of such, special mention may be made of liquid fatty acid esters that contain as the acid component a long-chained fatty acid having from 8 to 22, especially from 12 to 22, carbon atoms. The alcohol component of these fatty acid esters has a maximum of 6 carbon atoms and is a monovalent or polyvalent, for example a mono-, di- or trivalent, alcohol, especially glycol and glycerol. As mixtures of fatty acid esters, vegetable oils such as cottonseed oil, almond oil, olive oil, castor oil, sesame oil, soybean oil and groundnut oil are especially useful. The manufacture of injectable preparations is usually carried out under sterile conditions, as is the filling, for example, into ampoules or vials, and the sealing of the containers.

Suitable carriers are especially fillers, such as sugars, for example lactose, saccharose, mannitol or sorbitol, cellulose preparations, and/or calcium phosphates, for example tricalcium phosphate or calcium hydrogen phosphate, and also binders, such as starches, for example corn, wheat, rice or potato starch, methylcellulose, hydroxypropyl

methylcellulose, sodium carboxymethylcellulose, and/or polyvinylpyrrolidone, and/or, if desired, disintegrators, such as the above-mentioned starches, also carboxymethyl starch, crosslinked polyvinylpyrrolidone, alginic acid or a salt thereof, such as sodium alginate. Additional excipients are especially flow conditioners and lubricants, for example silicic acid, talc, stearic acid or salts thereof, such as magnesium or calcium stearate, and/or polyethylene glycol, or derivatives thereof. Tablet cores can be provided with suitable, optionally enteric, coatings through the use of, inter alia, concentrated sugar solutions which may comprise gum arabic, talc, polyvinylpyrrolidone, polyethylene glycol and/or titanium dioxide, or coating solutions in suitable organic solvents or solvent mixtures, or, for the preparation of enteric coatings, solutions of suitable cellulose preparations, such as acetylcellulose phthalate or hydroxypropyl- methylcellulose phthalate. Dyes or pigments may be added to the tablets or tablet coatings, for example for identification purposes or to indicate different doses of active ingredient.

Pharmaceutical compositions for oral administration also include hard capsules consisting of gelatin, and also soft, sealed capsules consisting of gelatin and a plasticizer, such as glycerol or sorbitol. The hard capsules may contain the active ingredient in the form of granules, for example in admixture with fillers, such as corn starch, binders, and/or glidants, such as talc or magnesium stearate, and optionally stabilizers. In soft capsules, the active ingredient is preferably dissolved or suspended in suitable liquid excipients, such as fatty oils, paraffin oil or liquid polyethylene glycols or fatty acid esters of ethylene or propylene glycol, to which stabilizers and detergents, for example of the polyoxy- ethylene sorbitan fatty acid ester type, may also be added.

Pharmaceutical compositions suitable for rectal administration are, for example, suppositories that consist of a combination of the active ingredient and a suppository base. Suitable suppository bases are, for example, natural or synthetic triglycerides, paraffin hydrocarbons, polyethylene glycols or higher alkanols.

For parenteral administration, aqueous solutions of an active ingredient in water-soluble form or aqueous injection suspensions that contain viscosity-increasing substances, for example sodium carboxymethylcellulose, sorbitol and/or dextran, and, if desired, stabilizers, are especially suitable. The active ingredient, optionally together with excipients, can also be in the form of a lyophilizate and can be made into a solution before parenteral administration by the addition of suitable solvents. Solutions such as are used, for example, for parenteral administration can also be employed as infusion solutions.

Preferred preservatives are, for example, antioxidants, such as ascorbic acid, or microbicides, such as sorbic acid or benzoic acid. Furthermore the invention relates to a method of treatment of angiogenesis dependent cancers and intraocular neovascular syndromes in a patient in need thereof, characterized in that a therapeutically effective amount of a compound of formula (I) as described hereinbefore as such or in form of a pharmaceutical preparation comprising it is administered to the patient in need thereof.

The compounds of formula (I) can be administered as such or especially in the form of pharmaceutical compositions, preferably in an amount effective against the said diseases, to a warm-blooded animal, for example a human, requiring such treatment. In the case of an individual having a bodyweight of about 70 kg the daily dose administered is from approximately 0.05 g to approximately 5 g, preferably from approximately 0.25 g to approximately 1.5 g, of a compound of the present invention.

Panvera Z'Lyte kinase assay. In vitro kinase activity was measured using the Panvera Z'Lyte Tyr1 kinase assay PV3190 (Invitrogen, USA), according to the manufacturer's instructions. Ten dilutions of compound in a three-fold series are measured, with the highest concentration being 10 μM. The reaction assay (10 μl) contains 7.5 ng of EphB4 kinase (Proqinase, Germany), 10 μM ATP, and 1% DMSO. The reaction is performed at room temperature for 2 hours. IC₅₀ values (inhibitor concentration at which enzyme activity is reduced by 50%) and fitted curves are determined with Origin 7.5 SR6 (OriginLab Software). Table 1: IC50 and % inhibition

Synthesis of compounds of the invention. Compounds of formula (I) are available by reaction of the potassium salt of 3-substituted 8-chloroxanthines 8 (or corresponding 8- bromoxanthines, see Priymenko, B.A., Samura, B.A., Garmash, S. N., Klyuev, N.A., and Romanenko, N. I., Pharmaceutical Chemistry Journal 1983, 17:105-108) with optionally substituted phenacyl halides 9 to give intermediate 10 which is cyclised by reaction with a primary amine R²-NH₂.

A compound of formula (I) wherein R¹ is a protecting group (such as benzyl) can be transformed to the corresponding compound wherein R¹ is methyl or ethyl by

hydrogenation and subsequent alkylation at N² with a corresponding alkylating agent, e.g. methyl or ethyl tosylate.

Xanthines of type 8 are readily available by standard condensation reactions of malonitriles with R²-substituted ureas in the presence of a strong base followed by amination, formylation and subsequent cyclization, then halogenation at C⁸ in

hydrochloric/acetic acid (or hydrobromic/acetic acid) and deprotonation at N⁷ with potassium carbonate. Examples

All reactions were carried out under a nitrogen atmosphere using Standard Schlenk-lines. All reagents were used as received unless otherwise noted. Solvents were purchased in the best quality available, degassed by purging thoroughly with nitrogen and dried over activated molecular sieves of appropriate size. Alternatively, they were purged with argon and passed through alumina columns in a solvent purification system (Innovative

Technology). Reactions were monitored by thin layer chromatography (TLC) using Merck TLC silica gel 60 F₂₅₄- Flash column chromatography was performed over silica gel (230- 400 mesh). NMR spectra were recorded on AV2 400 or AV2 500 MHz Bruker

spectrometers. Chemical shifts are given in ppm. The spectra are calibrated to the residual ¹H and ¹³C signals of the solvents. Multiplicities are abbreviated as follows: singlet (s), doublet (d), triplet (t), quartet (q), doublet-doublet (dd), quintet (quint), sextuplet (sext), septet (sept), multiplet (m), and broad (br). High-resolution electrospray ionization mass spectrometry was performed on a Finnigan MAT 900 (Thermo Finnigan, San Jose, CA; USA) doublefocusing magnetic sector mass spectrometer. Ten spectra were acquired. A mass accuracy < 2 ppm was obtained in the peak matching acquisition mode by using a solution containing 2 μl PEG200, 2 μl PPG450, and 1.5 mg NaOAc (all obtained from Sigma-Aldrich, CH-Buchs) dissolved in 100 ml MeOH (HPLC Supra grade, Scharlau, E- Barcelona) as internal standard. LC-MS analysis was done on a Finnigan Voyager GC8000 Top.

R¹= Me, Bn R¹= Me, Bn

General method for the cyclization to give alkylated xanthines 1 , 2, 5, and 6

A mixture of 3-alkyl-8-bromo-3,7-dihydro-7-(2-oxo-2-phenyl-ethyl)-1 H-purine-2,6-dione (1.0 eq) and the corresponding primary amine (4.0 eq) in EtOH (0.1 M) is heated in a sealed tube at 175 ⁰C for 12 h. The reaction mixture is cooled to room temperature, the solid is filtered off, and washed with water affording the corresponding products in pure form. This method was used to obtain LD-31 (1 ), LD-33 (2), LD-78 (5), and LD-79 (6). General method for the cyclization to give alkylated xanthines 3 and 4

A mixture of 3-alkyl-8-bromo-3,7-dihydro-7-(2-oxo-2-phenyl-ethyl)-1 H-purine-2,6-dione (1.0 eq) and butylamine (4.0 eq) in n-PrOH (0.1 M) is heated in a sealed tube at 175 ⁰C for 12 h. The reaction is cooled to room temperature, the solid is filtered off, and washed with water. Subsequent recrystallization in EtOH affords the corresponding product in pure form. This method was used to obtain LD-32 (3) and LD-45 (4).

8-(2-Methoxyphenyl)-1-methyl-7-o-methylphenyl-1 H-imidazor2.1-flDurine-2.4(3H.8H)- dione CI . LD-31 )

White solid; Yield: 64%; mp 301-303⁰C; ¹H NMR (400 MHz, DMSOd₆): δ = 10.98 (s, 1 H), 7.81 (s, 1 H), 7.49 (dd, J = 7.7, 1.6 Hz, 1 H), 7.39 (ddd, J = 8.6, 8.3, 1.6 Hz, 1 H), 7.21-7.22 (m, 2H), 7.13-7.15 (m, 1 H), 7.04-7.08 (m, 2H), 7.00 (ddd, J = 8.6, 7.7, 1.2 Hz, 1 H), 3.57 (s, 3H), 3.31 (s, 3H), 2.27 (s, 3H); ¹³C NMR (100 MHz, DMSO-d₆): δ = 154.8, 153.3, 152.9, 150.9, 147.7, 147.2, 144.6, 131.2, 129.5, 126.9, 122.6, 121.4, 120.8, 1 19.9, 112.9, 110.3, 108.5, 106.7, 101.1 , 99.0, 55.7, 28.8; IR (film): υ = 3166, 3007, 2811 , 1666, 1490, 1 157, 744 cm^"1; HRMS (ESI): m/z: calcd for C₂₂Hi₉N₅NaO₃: 424.1386, found: 424.1389 [M + Na]⁺. 8-(2-Methoxyphenyl)-1-methyl-7-m-hvdroxyphenyl-1 H-imidazor2.1-/1purine-2.4(3H.8H)- dione (2. LD-33)

White solid; Yield: 59%; mp 353-355 ⁰C; ¹H NMR (500 MHz, DMSO-d₆): δ = 10.97 (s, 1 H), 9.51 (s, 1 H), 7.88 (s, 1 H), 7.47-7.52 (m, 2H), 7.20 (d, J = 8.2 Hz, 1 H), 7.06-7.11 (m, 2H), 6.68-6.70 (m, 2H), 6.64 (s, 1 H), 3.60 (s, 3H), 3.29 (s, 3H); ¹³C NMR (125 MHz, DMSO-d₆): δ = 157.1 , 154.9, 153.3, 152.7, 150.9, 147.9, 133.1 , 131.1 , 129.7, 129.4, 129.2, 122.6, 120.9, 118.3, 115.4, 114.4, 112.9, 105.1,99.1,55.7,28.8; IR (film): υ =3147, 3030, 2817, 1676, 1482, 1299, 1159, 758 cm^"1; HRMS (ESI): m/z: calcd for C₂iH₁₇N₅Na0₄: 426.1178, found: 426.1181 [M + Na]⁺. 8-Butyl-1-methyl-7-m-hvdroxyDhenyl-1 H-imidazor2,1-flDurine-2,4(3H,8HVdione (3. LD^

White solid; Yield: 41%; mp 256-258⁰C; ¹H NMR (500 MHz, DMSOd₆): δ= 10.89 (s, 1H), 9.75 (s, 1 H), 7.59 (s, 1 H), 7.31 (t, J = 7.8 Hz, 1 H), 6.96 (d, J = 7.8 Hz, 1 H), 6.93 (s, 1 H), 6.88 (d, J = 7.8 Hz, 1 H), 4.07 (t, J = 7.3 Hz, 2H), 3.38 (s, 3H), 1.63 (quint, J = 7.3 Hz, 2H), 1.12 (sext, J =7.3 Hz, 2H), 0.74 (t, J = 7.3 Hz, 3H); ¹³C NMR (125 MHz, DMSOd₆): δ = 157.6, 153.2, 152.7, 150.9, 147.8, 132.3, 129.9, 129.0, 119.5, 116.0, 115.6, 104.7, 98.8, 43.3,30.2,28.8, 18.8, 13.1; IR (film): υ = 3297, 3166, 3046, 2963, 2864, 1675, 1512, 1459, 1312, 1148, 722 cm^"1; HRMS (ESI): m/z: calcd for Ci₈H₁₉N₅NaO₃: 376.1386, found: 376.1388 [M + Na]⁺.

8-Butyl-1-methyl-7-p-hvdroxyphenyl-1 H-imidazo[2,1-/1purine-2.4(3H.8HVdione (4. LD-45)

4

White solid; Yield: 10%; mp 277-281⁰C; ¹H NMR (400 MHz, DMSOd₆): δ= 10.89 (s, 1H), 9.85 (s, 1 H), 7.52 (s, 1 H), 7.36 (d, J = 8.7 Hz, 2H), 6.89 (d, J = 8.7 Hz, 2H), 4.04 (t, J = 7.3 Hz, 2H), 3.39 (s, 3H), 1.62 (quint, J= 7.3 Hz, 2H), 1.12 (sext, J= 7.3 Hz, 2H), 0.74 (t, J = 7.3 Hz, 3H); ¹³C NMR (100 MHz, DMSOd₆): δ= 158.2, 153.2, 152.6, 150.9, 147.6, 132.5, 130.5, 118.3, 115.6, 104.1,98.8,43.1,30.2,28.8, 18.8, 13.1; IR (film): υ = 3283, 3160, 3043,2973, 1676, 1510, 1226, 1148,843,716 cm^"1; HRMS (ESI): m/z: calcd for

Ci₈H₁₉N₅NaO₃: 376.1386, found: 376.1381 [M + Na]⁺.

8-(2-Methoxyphenyl)-1-methyl-7-(2^'-methyl-4^'-hvdroxyphenyl-1H-imidazo[2,1-/1purine- 2.4(3H.8H)-dione (5, LD-78)

White solid; Yield: 52%; mp 330-333 ⁰C; ¹H NMR (400 MHz, DMSOd₆): δ = 10.94 (s, 1 H), 9.55 (s, 1 H), 7.66 (s, 1 H), 7.38-7.43 (m, 2H), 7.09 (d, J = 7.5 Hz, 1 H), 7.00 (t, J = 7.5 Hz, 1 H), 6.94 (d, J = 8.3 Hz, 1 H), 6.57 (s, 1 H), 6.44 (d, J = 8.3 Hz, 1 H), 3.60 (s, 3H), 3.30 (s, 3H), 2.14 (s, 3H); IR (film): υ = 3208, 3048, 2942, 2838, 1675, 1596, 1455, 1205, 1 153, 747 cm^"1; HRMS (ESI): m/z: calcd for C₂₂Hi₉N₅NaO₄: 440.1335, found: 440.1330 [M + Na]⁺.

8-(2-Methoxyphenyl)-1-methyl-7-(2^'-methyl-5^'-hvdroxyphenyl-1 H-imidazo[2,1-/1purine- 2.4(3H.8H)-dione (6, LD-79)

White solid; Yield: 45%; mp 350-352 ⁰C; ¹H NMR (400 MHz, DMSOd₆): δ = 10.96 (s, 1 H), 9.22 (s, 1 H), 7.74 (s, 1 H), 7.39-7.44 (m, 2H), 7.10 (dd, J = 8.4, 0.9 Hz, 1 H), 6.97-7.04 (m, 2H), 6.62 (dd, J = 8.3, 2.6 Hz, 1 H), 6.56 (d, J = 2.6 Hz, 1 H), 3.61 (s, 3H), 3.30 (s, 3H), 2.12 (s, 3H); ¹³C NMR (100 MHz, DMSOd₆): δ = 154.6, 154.4, 153.3, 152.7, 150.9, 147.4, 131.8, 130.8, 130.7, 129.5, 127.8, 127.6, 122.2, 120.5, 117.7, 116.2, 112.6, 106.1 , 99.0, 55.5, 28.7, 18.6; IR (film): υ = 3296, 3145, 1698, 1670, 1593, 1505, 1282, 1 153, 1017, 751 cm^"1; HRMS (ESI): m/z: calcd for C₂₂H₁₉N₅NaO₄: 440.1335, found: 440.1333 [M + Na]⁺.

8-Butyl-1-ethyl-7-phenyl-1 H-imidazo[2.1-f1purine-2,4(3H.8HVdione (7. CR903-3464-56-1 )

8-(Butyl)-7-phenyl-1 H-imidazo[2,1-f]purine-2,4(3H,8H)-dione (1.0 equiv) was dissolved in anhydrous DMF (concentration, 0.05 M), and potassium carbonate (1.0 equiv) was added. After stirring 5 min at room temperature, the corresponding alkylating agent (1.0 equiv) was added dropwise. The reaction was stirred at room temperature for 15 h. Potassium carbonate was then removed by filtration, and the mixture was evaporated under reduced pressure. Purification by column chromatography on silica gel afforded the desired product as a white solid. ¹H NMR (400 MHz, DMSOd₆): δ = 10.92 (s, 1 H), 7.71 (s, 1 H), 7.52-7.60 (m, 5H), 4.12 (t, J = 7.1 Hz, 2H), 4.00 (q, J = 6.9 Hz, 2H), 1.60 (quint, J = 7.1 Hz, 2H), 1.25 (t, J = 6.9 Hz, 3H), 1.10 (sext, J = 7.1 Hz, 2H), 0.72 (t, J = 7.1 Hz, 3H); MS (LC/MS): m/z: calcd for Ci₉H₂₂N₅O₂: 352.4, found: 352.4 [M + H]⁺.

Claims

1. A compound of the formula (I)

wherein

R¹ is methyl or ethyl;

R² is n-butyl or o-methoxyphenyl;

R³ is hydrogen or hydroxy; and

R⁴ is hydrogen or methyl;

and tautomers and salts thereof.

2. The compound according to claim 1 of formula (I), wherein

R¹ is methyl;

R² is n-butyl or o-methoxyphenyl;

R³ is hydrogen, m-hydroxy or p-hydroxy; and

R⁴ is hydrogen or o-methyl;

with the proviso that at least one of R³ and R⁴ is different from hydrogen; and tautomers and salts thereof.

3. The compound according to claim 1 of formula (I), wherein

R¹ is ethyl;

R² is n-butyl; and

R³ and R⁴ are hydrogen;

and tautomers and salts thereof.

4. The compound according to claim 2 of formula (I), wherein

R¹ is methyl; R² is n-butyl;

R³ is m-hydroxy or p-hydroxy; and

R⁴ is hydrogen;

and tautomers and salts thereof.

5. The compound according to claim 2 of formula (I), wherein

R¹ is methyl;

R² is o-methoxyphenyl;

R³ is hydrogen, m-hydroxy or p-hydroxy; and

R⁴ is hydrogen or o-methyl;

6. The compound according to claim 2 of formula (I), wherein

R¹ is methyl, R² is o-methoxyphenyl, R³ is hydrogen, and R⁴ is methyl;

and tautomers and salts thereof.

7. The compound according to claim 2 of formula (I), wherein

R¹ is methyl, R² is o-methoxyphenyl, R³ is m-hydroxy, and R⁴ is hydrogen;

and tautomers and salts thereof.

8. The compound according to claim 2 of formula (I), wherein

R¹ is methyl, R² is n-butyl, R³ is m-hydroxy, and R⁴ is hydrogen;

and tautomers and salts thereof.

9. The compound according to claim 2 of formula (I), wherein

R¹ is methyl, R² is n-butyl, R³ is p-hydroxy, and R⁴ is hydrogen;

and tautomers and salts thereof.

10. The compound according to claim 2 of formula (I), wherein

R¹ is methyl, R² is o-methoxyphenyl, R³ is p-hydroxy, and R⁴ is o-methyl;

and tautomers and salts thereof.

1 1. The compound according to claim 2 of formula (I), wherein

wherein R¹ is methyl, R² is o-methoxyphenyl, R³ is m-hydroxy, and R⁴ is o-methyl; and tautomers and salts thereof.

12. A compound of formula (I) according to anyone of claims 1 to 1 1 for use in the treatment of angiogenesis dependent cancers and intraocular neovascular syndromes.

13. A pharmaceutical preparation comprising a compound of formula (I) according to anyone of claims 1 to 11.

14. A method of treatment of angiogenesis dependent cancers and intraocular neovascular syndromes in a patient in need thereof, characterized in that a therapeutically effective amount of a compound of formula (I) according to anyone of claims 1 to 1 1 or a pharmaceutical preparation according to claim 13 is administered to the patient in need thereof.