GB2279951A - Naphthopyran derivatives - Google Patents

Abstract

Pharmaceutical compounds of the formula (I): <IMAGE> in which n is 0-2, and each R<1> is halo, carboxy, trifluoromethyl, hydroxy, C1-4alkyl, C<1-4> alkoxy, C<1-4> alkylthio, hydroxy-C<1-4> alkyl, hydroxy-C<1-4> alkoxy, nitrogen-containing heterocyclyl, nitro, trifluoromethoxy, -COOR<7> where R<7> is an ester group, -COR<8>, -CONR<8>R<9> or -NR<8>R<9> where R<8> and R<9> are each hydrogen or C1-4 alkyl; R<2> and R<3> are each C1-4 alkyl; R<4> is phenyl, naphthyl or heteroaryl selected from thienyl, pyridyl, benzothienyl, quinolinyl, benzofuranyl or benzimidazolyl, said phenyl, naphthyl and heteroaryl groups being optionally substituted, or R<2> is furanyl optionally substituted with C1-4 alkyl; R<5> is nitrile, carboxy, -COOR<10> where R<10> is an ester group, or -CONR<11>R<12> where R<11> and R<12> are each hydrogen or C1-4 alkyl; and R<6> is -NR<13>R<14>, -NR<13>COR<14>, -N(COR<13>)2 or -N-CHOCH2R<13> where R<13> and R<14> are each hydrogen or C1-4 alkyl optionally substituted with carboxy, -N=CH-NR <15>R<16> where R<15> is hydrogen or C1-4 alkyl and R<16> is C1-4 alkyl, optionally substituted phenyl or optionally substituted heteroaryl, <IMAGE> where X is C2-4 alkylene. or -NHSO2R<17> where R<17> is C1-4 alkyl, trifluoromethyl or optionally substituted phenyl; and salts thereof, are useful in the treatment of immune diseases involving excess cell proliferation or enzyme release.

Description

PHARMACEUTICAL COMPOUNDS This invention relates to pharmaceutical compounds, their preparation and use.

The present invention relates to compounds of the formula (I):

in which n is 0, 1 or 2 and R1 is attached at any of the positions 7, 8, 9 or 10, and each R1 is halo, carboxy, trifluoromethyl, hydroxy, C1-4 alkyl, C14 alkoxy, C14 alkylthio, hydroxy-C1-4 alkyl, hydroxy-C1-4 alkoxy, nitrogen-containing heterocyclyl, nitro, trifluoromethoxy, -COOR7 where R7 is an ester group, -COR8, -CONR8R9 or -NR8R9 where R8 and R9 are each hydrogen or C14 alkyl; R2 and R3 are each C14 alkyl; R4 is phenyl, naphthyl or heteroaryl selected from thienyl, pyridyl, benzothienyl, quinolinyl, benzofuranyl or benzimidazolyl, said phenyl, naphthyl and heteroaryl groups being optionally substituted, or R2 is furanyl optionally substituted with C14 alkyl;; R5 is nitrile, carboxy, -COOR10 where R10 is an ester group, or -CONR11R12 where R11 and R12 are each hydrogen or C14 alkyl; and R6 is -NR13R14, -NR13CoRl4, -N(COR13)2 or -N=CHOCH2R13 where R13 and R14 are each hydrogen or C14 alkyl optionally substituted with carboxy, -N=CH-NR15R16 where R15 is hydrogen or C1-4 alkyl and R16 is C1-4 alkyl, optionally substituted phenyl or optionally substituted heteroaryl,

where X is C24 alkylene, or -NHSo2R17 where R17 is C14 alkyl, trifluoromethyl or optionally substituted phenyl; and salts thereof.

The compounds of the invention have been found to be active in tests which show their potential for treatment of immune diseases and diseases in which excess cell proliferation or enzyme release play a significant role.

In the above formula (I), halo is, for example, fluoro, chloro or bromo and is especially chloro. A C14 alkyl group includes, for example, methyl, ethyl, propyl and butyl, and is preferably methyl or ethyl. A Ca alkoxy group is one such alkyl group linked through oxygen to an aryl nucleus, and a C14 alkylthio is an alkyl group linked through sulphur. A hydroxyalkyl and hydroxyalkoxy are preferably of the formula HO(CH2)x and HO(CH2);,O-, respectively, where x is 1 to 4.

A substituted phenyl group is substituted with one or more, preferably one or two substituents each selected from halo, trifluoromethyl, C14 alkoxy, hydroxy, nitro, C14 alkyl, C1-4 alkylthio, hydroxy-C14 alkyl, hydroxy-C14 alkoxy, trifluoromethoxy, carboxy, -COOR18 where R18 is an ester group, -CONR19R20 or -NR19R20 where R19 and R20 are each hydrogen or C14 alkyl. When R18 is an ester group it is preferably C14 alkyl, especially methyl or ethyl. Substituted naphthyl and heteroaryl groups may be similarly substituted. In addition substituted phenyl includes a phenyl group in which neighbouring atoms are substituted by -O(CH2)mO-, where m is 1, 2 or 3.

When n is 1 or 2 and there are one or two substituents on the benzene nucleus they can be at any of the positions 7 to 10, and when there are two substituents they can be the same or different. It is preferred that the dihydronaphtho nucleus is unsubstituted or that it bears a single substituent at the 9-position.

When R1 is -CooR7, R7 can be any ester group and is preferably C1-; alkyl, especially methyl or ethyl.

When R1 is a nitrogen-containing heterocycle it is preferably selected from 2-pyridyl, 3-pyridyl, 4-pyridyl, l-piperidino, l-pyrrolidino and 4-morpholinyl.

When R2 and R3 are C14 alkyl they can each be, for example, methyl ethyl, propyl or butyl. R2 and R3 can be the same or different, and are preferably both methyl.

When R4 is heteroaryl it is preferably 2-thienyl, 3-thienyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-benzothienyl, 3-benzothienyl, 2-quinolinyl, 3-quinolinyl, 2-benzofuranyl, 3-benzofuranyl, 2-benzidimazolyl, 2-furanyl or 3-furanyl. A naphthyl group is attached at the 1- or 2- position. Such groups can be substituted at any of the available positions, but are preferably unsubstituted. Preferred values of R4 are 2-thienyl, 3-thienyl, 3-pyridyl, 4-pyridyl, phenyl or substituted phenyl.

A particularly preferred value of R4 is optionally substituted phenyl, preferably phenyl with a single substituent, especially nitro or trifluoromethyl.

The group R5 is preferably nitrile. When R5 is -COOR10, R10 can be any ester group and is preferably C14 alkyl, especially methyl or ethyl.

The group R6 is preferably -NR13R14, -NR13COR14 or -N(COR13)2 where R13 and R14 are each hydrogen or C14 alkyl,

or -NHSo2R17.

R6 is most preferably -NR13R14, for example, -NH2. When R6 is -NR13R14, R5 is preferably nitrile, carboxy or -CONR11R12, and especially nitrile or -CONR11R12 A preferred group of compounds for use in the present invention is of the formula (if):

in which R1 is hydrogen, C14 alkoxy, halo, hydroxy, carboxy, trifluoromethyl or trifluoromethoxy, R4 is -NH2, -NR13COR14 or -N(CCR14)2 where R13 is hydrogen or C14 alkyl and R14 is C14 alkyl, or

where X is C24 alkyene, and R21 is hydrogen, nitro, trifluoromethyl, halo, C14 alkoxy, trifluoromethoxy, carboxy or -COOR18 where R18 is an ester group.It is frequently preferred that the substituent group R21 is in the 3-position.

It will be appreciated that when, for example, R1 or R5 is carboxy or R4 is phenyl substituted by carboxy, an opportunity exists for salts to be formed.

They can be derived from any of the well known bases. Examples of base salts are those derived from ammonium hydroxide and alkali and alkaline earth metal hydroxides, carbonates and bicarbonates, as well as salts derived from aliphatic and aromatic amines, aliphatic diamines and hydroxy alkylamines. Bases especially useful in the preparation of such salts include ammonium hydroxide, potassium carbonate, sodium bicarbonate, lithium hydroxide, calcium hydroxide, methylamine, diethylamine, ethylene diamine, cyclohexylamine and ethanolamine. The potassium, sodium and lithium salt forms are particularly preferred.

In addition to pharmaceutically-acceptable salts, other salts are included in the invention. They may serve as intermediates in the purification of compounds or in the preparation of other, for example pharmaceuticallyacceptable, acid addition salts, or are useful for identification, charaterisation or purification.

In addition to salts formed with carboxy groups there can, of course, be esters formed with these same groups. Preferred esters are those derived from alcohols and especially C14 alcohols such as, for example, the methyl or ethyl esters.

It will be appreciated that the compounds of the invention contain an asymmetric carbon atom which gives rise to enantiomers. The compounds are normally prepared as racemates and can conveniently be used as such, but individual enantiomers can be isolated by conventional techniques if so desired. Such racemates and individual enantiomers form part of the present invention.

The invention also comprises a process for producing a compound of the formula (I) above, which comprises: (1) reacting a compound of the formula (III):

with malononitrile to give a compound of formula (I) in which R5 is nitrile and R6 is -NH2, (2) converting a compound of the formula (IV):

to a compound of formula (I) in which R6 is -NR13R14, -NR13COR14, -N(COR13)2, -N=CHOCH2R13, -N=CHR15R1 6, -N=CH-NR15R1 6,

or -NHSo2R17, or (3) converting a compound of the formula (V):

in which R6 is -NR13COR15 or -N(COR13)2 to a compound of formula (I) in which R5 is carboxy, -COOR10 or -CONR11R12.

With regard to process variant (1), the reaction is preferably carried out at a temperature of from 0 C. to 1000 C. and in the presence of an organic solvent, such as for example ethanol. Compounds of formula (III) can be easily synthesised by known methods. For example, they can be prepared from compounds of formula:

by reaction with an aldehyde of formula R4CHO in the presence of an acid catalyst such as, for example, toluene sulphonic acid, or when R4 is an acid sensitive group such as pyridyl, under basic conditions, with, for example, potassium hydroxide and ethanol. Compounds of formula (VI) are either known or can be prepared by standard methods.

With regard to process variant (2), the free enamine can be prepared by reaction (1) and subsequently converted to compounds in which Rt takes other values. For example, the free amino group can be alkylated with reagents of formula R13X or R14X where X is halogen, to give the mono- or di-alkylated product. Similarly the amino group can be acylated with an acylating reagent of formula R13COX or (R13CO)2O to give compounds in which R6 is -NR13COR14 or -N(COR13)2. Compounds in which R6 is -N=CHoCH2R13 are prepared by reaction with the appropriate trialkyl orthoformate, and those in which R6 is -NHSo2R17 by reaction with a sulphonyl halide of formula R17So-X.

Compounds in which R6 is -N=CH-NR15R16 can be made by reacting a compound in which R6 is -N=CHOCH2R13 with the appropriate amine.

With regard to process variant (3), compounds of formula (V) can be converted to those in which R5 is carboxy, -COOR10 or -CONR11R12 by conventional means. For example, the nitrile group is readily hydrolysed to carboxy which, in turn, can be esterified to give -COOR10, or reacted with amine to yield -CONR11R12. Compounds of the formula (V) can be prepared by acylation of compounds derived by process (1). Compounds in which R6 is other than -NR13COR14 and -N(COR13)2 can be prepared from the product of process 3 by removal of the acyl group or groups and subsequent reaction of the amino compound thus produced, with appropriate reagents.

As mentioned above, the compounds have pharmaceutical activity. They have an antiproliferative effect on cell division, and are thus indicated for use in the treatment of diseases where excess cell proliferation or enzyme release is an important aspect of the pathology.

For example, the compounds of the invention inhibit the natural proliferation of 3T3 fibroblasts at ICso concentrations of below 20 R molar.

Furthermore, the compounds have been shown to modify the immune response by inhibiting concanavalin A-induced T-cell proliferation in the test described by Lacombe P. et al., FEBS, 3048, 191, 227-230. In general the compounds of the invention have an IC50 value in this test of below 10 pM.

The compounds also inhibit phorbol ester-stimulated plasminogen activator synthesis in bovine retinal capillary endothelial cells.

Inhibition of macrophage-conditioned medium induced neutral protease release in chondrocytes has also been observed in the test described by K. Deshmukh-Phadke, M. Lawrence and S. Nanda, Biochem. Biophys. Res.

Commun., 1978, 85, 490-496.

Such properties show that the compounds have potential in the treatment of a wide range of diseases such as, for example, rheumatoid arthritis, atherosclerosis, cirrhosis, fibrosis and cancer, and for the treatment of auto-immune diseases such as, for example, systemic lupus, and in the prevention of graft rejection. They are also indicated for the treatment of osteoarthritis and diabetic complications.

Furthermore, compounds of the invention have been shown to inhibit vascular smooth cell proliferation. This has been demonstrated by using cultured smooth cells derived from rabbit aortae, proliferation being determined by the measurement of DNA synthesis. Cells are obtained by explant method as described in Ross, J. of Cell Bio. 50: 172 (1971). Cells are plated in 96 well microtiter plates for five days. The cultures become confluent and growth arrested. The cells are then transferred to Dulbecco's Modified Eagle's Medium (DMEM) containing 0.5 - 2t platelet poor plasma, 2 mM L-glutamine, 100 U/ml penicillin, 100 Rg ml streptomycin, 1 pC/ml 3H-thymidine, 20 ng/ml platelet-derived growth factor and varying concentrations of the compounds.Stock solution of compounds is prepared in dimethyl sulphoxide and then diluted to appropriate concentration (0.01 10 Fg/ml) in the above assay medium. Cells are then incubated at 370 C. for 24 hours under 5 Cm2/95% air. At the end of 24 hours, the cells are fixed in methanol. 3H thymidine incorporation in DNA was then determined by scintillation counting as described in Bonin et al., Exp. Cell Res. 181: 475-482 (1989).

Inhibition of smooth muscle cell proliferation by the compounds of the invention is further demonstrated by determining their effects on exponentially growing cells. Smooth muscle cells from rabbit aortae are seeded in 12 well tissue culture plates in DMEM containing 10t fetal bovine serum, 2 mM L-glutamine, 100 U/ml penicillin, and 100 zg/ml streptomycin.

After 24 hours, the cells are attached, the medium is replaced with DMEM containing 2% platelet poor plasma, 2 mM L-glutamine, 100 U/ml penicillin, 100 Rg/ml streptomycin, 40 ng/ml platelet-derived growth factor and indicated concentrations of the compounds. Cells are allowed to grow for four days. Cells are treated with trypsin and number of cells in each cultures is determined by counting using a ZM-Coulter counter.

Activity in the above tests indicates that the compounds of the invention are of potential in the treatment of restenosis, which is characterised by the migration and proliferation of smooth muscle cells in response to injury.

The invention also includes a pharmaceutical composition comprising a pharmaceutically-acceptable diluent or carrier in association with a compound of formula (I), or a pharmaceutically-acceptable salt thereof.

The compounds may be administered by various routes, for example, by the oral or rectal route, topically or parenterally, for example by injection, being usually employed in the form of a pharmaceutical composition. Such compositions form part of the present invention and are prepared in a manner well known in the pharmaceutical art and normally comprise at least one active compound in association with a pharmaceutically-acceptable diluent or carrier. In making the compositions of the present invention, the active ingredient will usually be mixed with a carrier, or diluted by a carrier, and/or enclosed with a carrier which may, for example, be in the form of a capsule, sachet, paper or other container. here the carrier serves as a diluent, it may be solid, semi-solid, or liquid material which acts as a vehicle, excipient or medium for the active ingredient.Thus, the composition may be in the form of tablets, lozenges, sachets, cachets, elixirs, suspensions, as a solid or in a liquid medium, ointments containing, for example, up to 10t by weight of the active compound, soft and hard gelatin capsules, suppositories, injection solutions and suspensions and sterile packaged powders.

Some examples of suitable carriers are lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, syrup, methyl cellulose, methyl- and propyl- hydroxybenzoate, talc magnesium stearate and mineral oil. The compositions of the injection may, as it well known in the art, be formulated so as to provide quick, sustained or delayed release of the active ingredient after administration to the patient.

When the compositions are formulated in unit dosage form, it is preferred that each unit dosage form contains from 5 mg to 500 mg, for example, from 25 mg to 200 mg. The term 'unit dosage form' refers to physically discrete units suitable as unit dosages for human subjects and animals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with the required pharmaceutical carrier.

The active compounds are effective over a wide dosage range and, for example, dosages per day will normally fall within the range of from 0.5 to 300 mg/kg, more usually in the range of from 5 to 100 mg/kg. However, it will be understood that the amount administered will be determined by the physician in the light of the relevant circumstances, including the condition to be treated, the choice of compound to be administered and the chosen route of administration, and therefore the above dosage ranges are not intended to limit the scope of the invention in any way.

The invention is illustrated by the following Examples.

EXAMPLE 1 A mixture of 4,4-dimethyl-l-tetralone (1.74 g) and 3-nitrobenzaldehyde (1.51 g) was diluted with a solution of potassium hydroxide (0.4 g) in 95:5 ethanol/water (10 ml) and the mixture stirred at room temperature. The solids rapidly dissolved yielding a red solution. Within a few minutes, a precipitate appeared. After 24 hours, the mixture was acidified with glacial acetic acid. The resulting pale yellow solid was filtered off, washed well with water and dried in vacuo, yielding 4,4-dimethyl-2-(3 nitrobenzylidene)-1-tetralone (2.7 g).

A mixture of 4,4-dimethyl-1-tetralone (1.74 g), 3,4-dimethoxybenzaldehyde (1.66 g) and p-toluenesulphonic acid (20 mg) in toluene (50 ml) was stirred and heated at reflux with separation of water. After 8 hours, the solution was cooled and the solution washed with acqeous sodium bicarbonate solution and then dried (MgSO4). Concentration after filtration yielded a red gum.

This was crystallised from ether/hexane to yield 2-(3,4 dimethoxybenzylidene) -4, 4-dimethyl-1-tetralone.

Prepared in the same way were: 4,4-Dimethyl-2-(3-trifluoromethylbenzylidene)-1-tetralone 2-(3,4-Difluorobenzylidene)-4,4-dimethyl-1-tetralone 4,4-Dimethyl-2-(3-pyridylmethylene)-1-tetralone was prepared by the procedure described in the literature for the corresponding non-methylated compound (J. Sam and K. Aparajithan, J. Pharm. Sci., 1967,56 (5), 644).

EXAMPLE 2 To a stirred solution of 4,4-dimethyl-2-(3-nitrobenzylidene) 1-tetralone (1.2 g) and malonitrile (387 mg) in dimethylformamide (6 ml) was added piperidine (5 drops). The black solution was stirred at room temperature for 48 hours. The solution was then concentrated in vacuo and the red oily residue partitioned between water and dichloromethane. The organic layer was washed with water and dried (MgSO4). Concentration after filtration yielded a red gum that was crystallised from ether/hexane. This orange solid was washed with isopropanol then hexane and dried in vacuo, yielding 2-amino-6,6-dimethyl-4-(3-nitrophenyl)-4H-5,6-dihydronaphthol[1,2-b]pyran 3-carbonitrile as a pale yellow solid, m.p. 180-1830 C.

Prepared in a similar manner were: 2-Amino-4-(3,4-dimethOxyphenyl)-6,6-dimethyl-4H-5,6-dihydronaphtho[1,2- b]pyran 3-carbonitrile, m.p. 177-1800 C.

2-Amino-6,6-dimethyl-4-(3-trifluoromethylphenyl)-4H-5,6-dihydronaphthor1,2- b]pyran 3-carbonitrile, m.p. 164-1650 C.

2-Amino-4-(3,4-difluorophenyl)-6,6-dimethyl-4H-5,6-dihydronaphtho[1,2- b]pyran 3-carbonitrile, m.p. 177-178 C.

2-Amino-6,6-dimethyl-4-(3-pyridyl)-4H-5,6-dihydronaphtho[1,2-b]pyran 3-carbonitrile, m.p. 200-2020 C.

EXAMPLE 3 Soft gelatin cansule Each soft gelatin capsule contains: Active ingredient 150 mg Arachis oil 150 mg After mixing together, the blend is filled into soft gelatin capsules using the appropriate equipment.

EXAMPLE 4 Hard gelatin capsule Each capsule contains: Active ingredient 50 mg PEG 4000 250 mg The PEG 4000 is melted and mixed with the active ingredient. Whilst still molten the mixture is filled into capsule shells and allowed to cool. EXAMPLE 5 Tablets each containing 10 mg of active ingredient are made up as follows: Active ingredient 10 mg Starch 160 mg Microcrystalline cellulose 100 mg Polyvinylpyrrolidone (as 10t solution in water) 13 mg Sodium carboxymethyl starch 14 mg Magnesium stearate 3 mg Total 300 mg The active ingredient, starch and cellulose are mixed thoroughly. The solution of polyvinylpyrrolidone is mixed with the resultant powders and passed through a sieve. The granules so produced are dried and re-passed through a sieve. The sodium carboxymethyl starch and magnesium stearate are then added to the granules which, after mixing, are compressed in a tablet machine to yield tablets each weighing 300 mg.

EXAMPLE 6 Capsules each containing 20 mg of medicament are made as follows: Active ingredient 20 mg Dried starch 178 mg Magnesium stearate 2 mg Total 200 mg The active ingredient, starch and magnesium stearate are passed through a sieve and filled into hard gelatin capsules in 200 mg quantities.

Claims (7)

1. A compound of the formula (I):

in which n is 0, 1 or 2 and R1 is attached at any of the positions 7, 8, 9 or 10, and each R1 is halo, carboxy, trifluoromethyl, hydroxy, C14 alkyl, C14 alkoxy, C14 alkylthio, hydroxy-C1- alkyl, hydroxy-C1-4 alkoxy, nitrogen-containing heterocyclyl, nitro, trifluoromethoxy, -COOR7 where R7 is an ester group, -COR8, -CONR8R9 or -NR8R9 where R8 and R9 are each hydrogen or C14 alkyl; R2 and R3 are each C14 alkyl; R4 is phenyl, naphthyl or heteroaryl selected from thienyl, pyridyl, benzothienyl, quinolinyl, benzofuranyl or benzimidazolyl, said phenyl, naphthyl and heteroaryl groups being optionally substituted, or R2 is furanyl optionally substituted with C14 alkyl;; R5 is nitrile, carboxy, -COOR10 where R10 is an ester group, or -C0MR11R12 where R11 and R12 are each hydrogen or C14 alkyl; and R6 is -NR13R14, -NR13COR14, -N(COR13)2 or -N=CHOCH2R13 where R13 and R14 are each hydrogen or C1-4 alkyl optionally substituted with carboxy, -N=CH-NR15R16 where R15 is hydrogen or C1-4 alkyl and R16 is C1-4 alkyl, optionally substituted phenyl or optionally substituted heteroaryl,

where X is C2-4 alkylene, or -NHSO2R17 where R17 is C14 alkyl, trifluoromethyl or optionally substituted phenyl; or a salt thereof.

2. A compound according to Claim 1, in which R2 and R3 are both methyl.

3. A compound according to either of Claims 1 and 2, in which R is -NR13R14.

4. A compound of the formula:

in which R1 is hydrogen, C14 alkoxy, halo, hydroxy, carboxy, trifluoromethyl or trifluoromethoxy, R4 is -NH2, -NR13COR14 or -N(COR14)2 where R13 is hydrogen or C14 alkyl and R14 is C1-4 alkyl, or

where X is C2-4 alkyene, and R21 is hydrogen, nitro, trifluoromethyl, halo, C1 ; alkoxy, trifluoromethoxy, carboxy or -COOR1 where R18 is an ester group; or a salt thereof.

5. A compound according to Claim 1 or a pharmaceutically-acceptable salt thereof, for use as a pharmaceutical.

6. A pharmaceutical formulation comprising a compound according to any of Claims 1 to 4 or a pharmaceutically-acceptable salt thereof, together with a pharmaceutically-acceptable diluent or carrier therefor.

7. A process for producing a compound according to Claim 1, which comprises: (1) reacting a compound of the formula (III):

with malononitrile to give a compound of formula (I) in which R5 is nitrile and R6 is -NH2, (2) converting a compound of the formula (IV):

to a compound of formula (I) in which R6 is -NR13Rl4, -NRl3COR14 -N(COR13)2, -N=CHOCH2R13, -N=CHR15R5, -N=CH-NR15Rl5,

or -NHSo2R17, or (3) converting a compound of the formula (V):

in which R6 is -NR13COR15 or -N(COR13)2 to a compound of formula (I) in which R5 is carboxy, -COOR10 or -CONR11R12.