INDENE DERIVATIVES AND METHODS

Abstract: Indene derivatives of the general formula wherein R¹ is a) a phenyl group optionally substituted with one or more groups selected from halogen, lower alkyl, lower alkoxy, lower alkylthio, lower alkylsulfonyl, dilower alkylamino, acylamino such as acetylamino, cyano, trifluoromethyl, trifluoromethoxy, pyrrole and dilower alkylpyrrole, b) a polycyclic aromatic or heteroaromatic group, such as naphthalene or quinoline, c) a heteroaromatic group such as thiophene, pyridine and pyrrole, optionally substituted with one or more groups selected from halogen, lower alkyl, lower alkoxy, lower alkylthio, trifluoromethyl or trifluoromethoxy, R² is selected from H, halogen , lower alkyl, benzyl, lower alkylthio, lower alkyl­ sulfonyl, dilower alkylsulfamoyl, acylamino such as acetylamino, benzylamino, dilower alkylamino, cyano, pyrrole, dilower alkylpyrrole, trifluoromethyl and trifluoromethoxy, R³ is CN, COOR⁴, -CON(R⁴)₂ or COR⁴, where R⁴ is a lower alkyl group, and "n" is an integer of from 1 - 3 inclusive. The compounds are valuable intermediates in the preparation of pharmacologically active indane and indene derivatives. Methods are also described.

Description: The present invention relates to novel indene derivatives with the general formula I: wherein R¹ is a ) a phenyl group optionally substituted with one or more groups selected from halogen, lower alkyl, lower alkoxy, lower alkylthio, lower alkylsulfonyl, di-lower alkylamino, acylamino such as acetylamino, cyano, trifluoromethyl, trifluoromethoxy, pyrrole and di-lower alkylpyrrole, b ) a naphthyl group or a quinolinyl group, c ) a group selected from thiophene, pyridine and pyrrole, optionally substituted with one or more groups selected from halogen, lower alkyl, lower alkoxy, lower alkylthio, trifluoromethyl or trifluoromethoxy, R² is selected from H, halogen, lower alkyl, lower alkoxy, nitro, benzyl, lower alkylthio, lower alkylsulfonyl, di-lower alkylsulfamoyl, acylamino such as acetylamino, benzylamino, di-lower alkylalmino, cyano, pyrrole, di-lower alkylpyrrole, trifluoromethyl and trifluoromethoxy, R³ is CN, COOR⁴, -CON(R⁴)₂ or COR⁴, where R⁴ is a lower alkyl group, and "n" is an integer of from 1 - 3 inclusive. The indene derivatives of formula I are, when R¹ is as defined under a) above, valuable intermediates which are useful in the preparation of pharmacologically effective indane and indene derivatives known from e.g. US-Patents Nos. 4,443,448 and 4,525,360. Moreover, the invention relates to a method for the preparation of the compounds of formula I and to a method for the preparation of compounds of the following formula IV: wherein R¹, R² and "n" are as defined above. The compounds of formula IV, wherein R¹ is as defined under a) above, are known from US-Patents Nos. 4,443,448 and 4,525,360 and are themselves valuable intermediates for the preparation of pharmacologically active indanes and indenes known from the aforesaid US-patents. The novel indenes of Formula I make it also possible to prepare the intermediates IV in excellent yield and with a variation in the substituent R¹ of a much wider scope than the method described in the abovementioned US-Patents. According to the present invention is has surprisingly been found that 2-halogenobenzonitriles undergo extremely easy nucleophilic aromatic substitution of halogen with carbanions generated from aryl- and heteroarylacetonitriles thereby producing compounds of the general Formula II in the following scheme. The compounds of Formula II may either be isolated in excellent yields or further reacted in situ with halogenoacetic acid derivatives or with lower alkyl-halogenomethyl ketones. The products thus formed undergo spontaneous cyclisation, thereby forming the compounds of formula I. The sequence of reactions may be illustrated in the following reaction scheme: wherein X is halogen, preferably F, Cl or Br, Y is Cl, Br or I, and R¹, R², R³ and "n" are as defined above. The compounds of formula I may alternatively be prepared by reacting 2-halogenobenzonitriles with 3-cyano-3-arylpropionic acid derivatives or which 3-cyano-3-heteroarylpropionic acid derivatives, with 4-(lower alkyl)-4-oxo-2-arylbutyronitriles or with 4-(lower alkyl)-4-oxo-2-heteroarylbutyronitriles according to the following reaction scheme: According to the present invention the compounds of formula I may easily be converted to the compounds of formula IV. The conversion may be illustrated by the following reaction scheme: The method of the invention comprises a) reacting a 2-halogenobenzonitrile of formula V: wherein R², X and "n" are as defined above, with a compound of the formula: R¹CH₂CN, wherein R¹ is as defined above, in an aprotic organic solvent and in an inert atmosphere, in the presence of an alkaline substance producing the compound with formula II: which may either be 1) isolated and further reacted in an organic solvent with a compound of formula: YCH₂R³, wherein Y and R³ are as defined above, thereby producing a compound of formula I, or 2) further reacted in situ with a compound of the formula: YCH₂R³, thereby producing a compound of formula I, or b) reacting a 2-halogenobenzonitrile of formula V with a compound of formula: R¹-CHCN-CH₂R³, wherein R¹ and R² are as defined above, in an aprotic organic solvent and in an inert atmosphere, in the presence of an alkaline substance, whereupon the resulting compound of formula I is isolated. The methods a) and b) are carried out in an aprotic organic solvent, such as N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), 1,2-dimethoxyethane (DME), tetrahydrofuran (THF) or the like, in an inert atmosphere, preferably under anhydrous conditions, and in the presence of an alkaline substance, such as an alkali metal alcoholate, such as potassium tert-butoxide, sodium hydride, sodium amide or an alkali metal carbonate such as potassium or cesium carbonate, preferably at temperatures between 15°C and 60°C. The present invention further provides a method for the preparation of compounds of Formula VI, which comprises: heating a compound of formula I wherein R¹, R², R³ and "n" are as defined above, under hydrolytic conditions, optionally under oxidative conditions, and isolating the compound of formula III: and heating the compound of formula III in a basic organic solvent, whereupon the indane of formula IV is isolated. According to this method of preparation of indanes of formula III the compounds of formula I for which R³ is CN, COOR⁴ or CON(R⁴)₂, wherein R⁴ is as defined above, undergo hydrolysis and decarboxylation, preferably upon heating in mixtures of acetic acid, sulfuric acid and water, in mixtures of methanesulfonic acid and water or in mixtures of acetic acid and concentrated hydrochloric acid at temperatures between about 100°C and 120°C, thereby forming the compounds of formula III. The compounds of formula I for which R³ is COR⁴, wherein R⁴ is as defined above, undergo the oxidative Baeyer-Villiger rearrangement, known e.g. from Jerry March: "Advanced Organic Chemistry", 3.Ed., Wiley-Interscience New York 1985, upon treatment with peroxycarboxylic acids such as trifluoroperoxyacetic acid or meta-chloroperoxybenzoic acid (MCPBA) in inert organic solvents. The resulting compounds are subsequently hydrolyzed and decarboxylated as described above for the compounds of formula I for which R³ is CN, COOR⁴ or CON(R⁴)₂, thereby forming the compounds of formula III. The subsequent conversion of the compounds of formula III into the indanes of formula IV is preferably carried out in weakly basic organic solvents such as pyridine, quinoline and N-methylpyrrolidone (NMP), optionally diluted with an inert organic solvent such as toluene, at temperatures between about 60 and 120°C. The term "lower" in the foregoing and in the claims means from 1 - 6 carbon atoms inclusive, preferably from 1 - 4 carbon atoms inclusive. In the novel indene derivatives of formula I, R¹ is preferably a phenyl group optionally substituted with one or two groups selected from chloro, fluoro, methyl, methoxy, acetylamino or trifluoromethyl, a pyrrole group optionally substituted with methyl or methoxy, a thiophene ring optionally substituted with methyl or fluoro, a pyridine ring optionally substituted with methyl or fluoro or a naphthyl ring; R² is H, Cl, Br, F, CH₃, CH₃O or CF₃; R³ is COOCH₃, -CN or -CON(CH₃)₂, and "n" is 1. The methods of the invention shall in the following be illustrated by some examples which may not be construed as limiting. EXAMPLE 1 1-Amino-3-cyano-3-(4-fluorophenyl)-6-nitro-1-inden-2-carboxylic acid methyl ester A suspension of 43.o gr 3-cyano-3-(4-fluorophenyl)-propionic acid methylester, 40.o gr 2-chloro-5-nitrobenzonitrile, 34.5 gr potassium carbonate and 7.5 gr tetrabutylammoniumhydrogen sulfate in 200 ml N,N-dimethylformamide (DMF) is stirred for 90 hrs at 50°C. The mixture is cooled and poured into 200 ml toluene. 500 ml dilute hydrochloric acid are added gradually, and the mixture is stirred for 2 hrs at ambient temperature. The crystallized product is isolated by filtration and purified with cold toluene. Yield: 46.o gr (62% of the theoretical amount). Mp. (from ethanol): 286-289°C. EXAMPLE 2 1-Amino-3-cyano-3-(4-fluorophenyl)-6-trifluoromethyl-1-inden-2-carboxylic acid methylester The following operations are performed under dry nitrogen. To a well-stirred suspension of 10.25 kg potassium tert -butoxide in 30 litres 1,2-dimethoxyethane (DME) is added gradually a solution of 6 kg 4-fluorobenzylcyanide and 9.6 kg 2-chloro-5-trifluoromethylbenzonitrile in 15 ltr DME, maintaining an internal temperature of approx. 20°C. The reaction mixture is subsequently stirred for one hour at ambient temperature. 9.7 kg methylchloroacetate is added gradually, and the mixture is stirred overnight at ambient temperature. The following day the reaction mixture is heated to 60°C and stirred for 3 hours. The reaction mixture is cooled and quenched with dilute acetic acid. The main part of the solvent (DME) is removed in vacuo , and subsequent work-up in the usual manner gives the product 1-amino-3-cyano-3-(4-fluorophenyl)-6-trifluoromethyl-1-inden-2-carboxylic acid methylester. Yield: 13.84 kg (83% of the theoretical amount). Mp. (from ethanol): 178-179°C. EXAMPLE 3 1-Amino-3-cyano-3-(4-fluorophenyl)-1-inden-2-carboxylic acid methyl ester The following operations are performed under dry nitrogen. To a stirred solution of 234.6 gr potassium tert .-butoxide in 800 ml N,N-dimethylformamide (DMF) is added gradually a solution of 135.1 gr 4-fluorobenzylcyanide and 144.5 gr 2-chlorobenzonitrile in 400 ml DMF, maintaining an internal temperature between 25°C and 30°C (ice bath). The reaction mixture is subsequently stirred for 1 hour at ambient temperature. 115 ml methylchloroacetate are added gradually, and the reaction mixture is stirred overnight at ambient temperature. The following day the reaction mixture is heated to 50°C and stirred for 2 hrs., cooled and poured into a mixture of 3.5 ltr dilute hydrochloric acid, 500 ml n-heptane and 250 ml toluene. The product crystallizes within an hour and is isolated by filtration of the suspension. The crystalline product is purified with additional amounts of water (2 x 500 ml), toluene (2 x 100 ml) and n-heptane (2 x 250 ml). The productis dried in vacuo at 60°C overnight. Yield: 260.6 gr (84.5% of the theoretical amount). Mp. 198-202°C. EXAMPLE 4 1-Amino-6-chloro-3-cyano-3-(thien-3-yl)-1-inden-2-carboxylic acid methyl ester The following operations are performed under dry nitrogen. To a stirred suspension of 18.9 gr potassium tert -butoxide in 75 ml anhydrous 1,2-dimethoxyethane (DME) is added gradually a solution of 15.o gr 2,5-dichlorobenzonitrile and 10.0 gr thiophene-3-acetonitrile in 150 ml anhydrous DME, maintaining an internal temperature between 15°C and 20°C (ice bath). The reaction mixture is subsequently stirred for 15 minutes at 20°C and cooled to 10°C. 25 ml methylchloroacetate are added gradually, and the reaction mixture is stirred overnight at ambient temperature. The following day the reaction mixture is quenched with dilute hydrochloric acid. Extractive work-up with diethyl ether in the usual manner gives 20.o gr crystalline product (74% of the theoretical amount). Melting point (recryst. from ethanol): 199-201°C. EXAMPLE 5 2-Cyano-4′-fluorobenzhydrylcyanide The following operations are performed under dry nitrogen. To a stirred solution of 700 gr potassium tert -butoxide in 3.6 ltr N,N-dimethylformamide (DMF) is added gradually a solution of 401.4 gr 4-fluorobenzylcyanide and 429.2 gr 2-chlorobenzonitrile in 1.2 ltr DMF, maintaining an internal temperature between 25°C and 30°C (ice bath). The reaction mixture is subsequently stirred for one hour at ambient temperature and quenched with dilute hydrochloric acid. Extractive work-up with diethylether gives the product 2-cyano-4′-fluorobenzhydrylcyanide. Yield 602.1 gr (85.8% of the theoretical amount). Mp. 87-89°C. EXAMPLE 6 1-Amino-2-acetyl-3-cyano-3-(4-fluorophenyl)-1-indene The following operations are performed under dry nitrogen. 5.0 gr 2-cyano-4′-fluorobenzhydrylcyanide are added to a well-stirred suspension of 4.4 gr anhydrous potassium carbonate in 25 ml DMF. The reaction-mixture is stirred efficiently for 30 minutes, and 5.0 gr chloroacetone are added gradually with cooling. The resulting reaction-mixture is stirred for 48 hours at ambient temperature. Subsequent extractive work-up with diethyl ether gives the product 1-amino-2-acetyl-3-cyano-3-(4-fluorophenyl)-1-inden . Yield: 4.9 gr (79% of the theoretical amount). Mp. 190-192°C. EXAMPLE 7 3-carboxy-3-(4-fluorophenyl)-indan-1-one A mixture of 50.0 gr 1-amino-3-cyano-3-(4-fluorphenyl)-1-inden-2-carboxylic acid methylester and 250 ml glacial acetic acid is heated to about 90°C and stirred for about 15 minutes until a homogenous solution is formed. A mixture of 80 ml concentrates sulfuric acid and 40 ml water is added gradually maintaining an internal temperature of 90°-100°C. The temperature is subsequently raised to 110°C, and the reaction-mixture is stirred at this temperature for 4 hours and poured into crushed ice. Extractive work-up with toluene gives the product 3-carboxy-3-(4-fluorophenyl)-indan-1-one . Yield: 40.0 gr (91.0% of the theorectical amount). Mp. 106-108°C. EXAMPLE 8 3-(4-fluorophenyl)-indan-1-one The following operations are performed under dry nitrogen. A solution of 40.0 gr 3-carboxy-3-(4-fluorophenyl)-indan-1-one in 50 ml N-methylpyrrolidone is heated to 100°C and stirred for 2 hours at this temperature. The reaction-mixture is cooled and poured into 250 ml water. Subsequent extractive work-up with ethylacetate give the product 3-(4-fluorophenyl)-indan-1-one . Yield: 28.5 gr (85.0% of the theorectial amount). Mp. 120-121°C The compounds of Formula I, which have been prepared under conditions equivalent to those described in examples 1-4, and 6, are listed in the following scheme:

Claims: Claims for the following Contracting States : AT, BE, CH, DE, FR, GB, IT, LI, LU, NL, SE An indene derivative of the general formula I: wherein R¹ is a ) a phenyl group optionally substituted with one or more groups selected from halogen, lower alkyl, lower alkoxy, lower alkylthio, lower alkylsulfonyl, di-lower alkylamino, acylamino such as acetylamino, cyano, trifluoromethyl, trifluoromethoxy, pyrrole and di-lower alkylpyrrole, b ) a naphthyl group or a quinolinyl group, c ) a group selected from thiophene, pyridine and pyrrole, optionally substituted with one or more groups selected from halogen, lower alkyl, lower alkoxy, lower alkylthio, trifluoromethyl or trifluoromethoxy, R² is selected from H, halogen, lower alkyl, lower alkoxy, nitro, benzyl, lower alkylthio, lower alkylsulfonyl, di-lower alkysulfamoyl, acylamino such as acetylamino, benzylamino, di-lower alkylamino, cyano, pyrrole, di-lower alkylpyrrole, trifluoromethyl and trifluoromethoxy, R³ is CN, COOR⁴, -CON(R⁴)₂ or COR⁴, where R⁴ is a lower alkyl group, and "n" is an integer of from 1 - 3 inclusive. An indene derivative according to Claim 1, wherein R¹ is a phenyl group optionally substituted with one or two groups selected from chloro, fluoro, methyl, methoxy, acetylamino and trifluoromethyl, a pyrrole group optionally substituted with methyl or methoxy, a thiophene ring optionally substituted with methyl, chloro or fluoro, a pyridine ring optionally substituted with methyl or fluoro; or a naphthalene ring; R² is hydrogen, chloro, bromo, fluoro, methyl, methoxy or trifluoromethyl; R³ is -COOCH₃, -CN or -CO N(CH₃)₂, and "n" is 1. An indene derivative according to Claim 1 or 2, wherein R¹ is a phenyl group optionally substituted with chloro, fluoro or trifluoromethyl; R² is hydrogen, chloro, fluoro, methyl, methoxy or trifluoromethyl in the 6-position; R³ is -COOCH₃, -CN or -CO N(CH₃)₂, and "n" is 1. An indene derivative according to Claim 1 or 2, wherein R¹ is a thiophene ring optionally substituted with methyl or fluoro; R² is hydrogen, chloro, fluoro, methyl, methoxy or trifluoromethyl in the 6-position; R³ is -COOCH₃, -CN or CO N(CH₃)₂, and "n" is 1. 1-Amino-3-cyano-3(3,4-dichlorophenyl)-1-inden-2-carboxylic acid methyl ester. 1-Amino-3-cyano-3-(4-fluorophenyl)-6-chloro-1-inden-2-carboxylic acid methyl ester. 1-Amino-3-cyano-3-(4-fluorophenyl)-1-inden-2-carboxylic acid methyl ester. 1-Amino-3-cyano-3-(thienyl-3)-6-chloro-1-inden-2-carboxylic acid methyl ester. 1-Amino-3-cyano-3-(thienyl-3)-1-inden-2-carboxylic acid methyl ester. A method for the preparation of an indene derivative as defined in Claim 1, which comprises: a) reacting a 2-halogenobenzonitrile of formula V: wherein R² and "n" are as defined in Claim 1, and X is halogen, with a compound of the formula: R¹CH₂CN, wherein R¹ is as defined in Claim 1, in an aprotic organic solvent and in an inert atmosphere, in the presence of an alkaline substance, producing the compound with formula II: which may either be 1) isolated and further reacted in an organic solvent with a compound of formula: YCH₂R³, wherein Y is Cl, Br or I, and R³ is as defined in Claim 1, thereby producing a compound of formula I, or 2) further reacted in situ with a compound of the formula: YCH₂R³, thereby producing a compound of formula I. or b) reacting a 2-halogenobenzonitrile of formula V with a compound of formula: R¹-CHCN-CH₂R³, wherein R¹ and R² are as defined above, in an aprotic organic solvent, and in an inert atmosphere, in the presence of an alkaline substance whereupon the resulting compound of formula I is isolated. A method according to Claim 10, wherein R¹, R², R³ and "n" are as defined in Claim 2. A method according to Claim 10 or 11, wherein R¹, R², R³ and "n" are as defined in Claim 3. A method for the preparation of a compound of the following formula wherein R¹ and R² are as defined in Claim 1, which comprises: heating a compound of formula I wherein R¹, R², R³ and "n" are as defined in Claim 1, under hydrolytic conditions, optionally under oxidative conditions, and isolating the compound of formula III: and heating the compound of formula III in a basic organic solvent, whereupon the indane of formula IV is isolated.

Inventors: BOGESO, KLAUS PETER, SOMMER, MICHAEL BECH
Applicants: H. LUNDBECK A/S
Application year: 1987
Main classification: C07C255
IPC codes: C07C62, C07C323, C07C49, C07C45, C07C311, C07C253, C07D317, C07C255, C07D207, C07C317, C07D333, C07C67, C07C315, C07D213, C07C319