Patent GB-1198212-A (GB)
Title: 4-Aminophenyl Acetic Acid Derivatives and Preparation thereof
Inventor: SCHORSCHER ERNEST
IPC: C07D295/096
Filed: 1968-07-18
Abstract: 1,198,212. 4-Aminophenylacetic acid derivatives. E. MERCK A.G. 18 July, 1968 [22 July, 1967; 8 Jan., 1968; 23 Feb., 1968; 1 March, 1968], No. 34381/68. Heading C2C. Novel compounds of Formula I wherein R 1  and R 2 , which may be the same or different, are H or alkyl groups containing from 1 to 4 carbon atoms, R 3  is F, Hal, CF 3 , OH, NO 2 , CN, R 9 , OR 9 , SH, SR 9 , NR 1 COR 9 , NR 1 R 2 , SO 2 NR 1 R 2 , SOR 9  or SO 2 R 9 , R 4 , R 5  and R 6  are H or, in any one compound, one of the radicals R 4 , R 5  and R 6  is F, Hal, R 9 , OR 9  or SR 9  or R 4  and R 5  together form a tetramethylene group containing from 0 to 2 double bonds, in which case R 3  may additionally be H and R 6  may additionally be H, F, Hal, CF 3 , OH, NO 2 , CN, R 9 , OR 9 , SR 9 , NR 1 COR 9 , NR 1 R 2 , SO 2 NR 1 R 2 , SOR 9  or SO 2 R 9 ; R 7  and R 8 , which may be the same or different, are linear or branched alkyl groups containing from 1 to 7 carbon atoms or together form a linear or branched alkylene group containing from 2 to 14 carbon atoms, the carbon chain of which may be interrupted by an oxygen or sulphur atom; R 9  is an alkyl group containing from 1 to 4 carbon atoms, A is COOA 1 , CONA 2 A 3 , CONA 4 , C(=NOH)OH or C(OR 9 ) 3 , A 1 , A 2  and A 3 , which may be the same or different, are H, an alkyl or cycloalkyl group containing up to 12 carbon atoms, which group may contain 1 or 2 carbon multiple bonds and/or one OH and/or one NH 2  group and the carbon chain of which may be interrupted from one to three times by O and/or by Y and may be branched, or a phenyl or aralkyl group containing from 6 to 14 carbon atoms, or are A 5 -NA 4 ; A 4  is an alkylene group containing up to 6 carbon atoms, the carbon chain of which may be interrupted by O or Y, A 5  is an alkylene group containing from 1 to 6 carbon atoms; and Y denotes S, NH, an N-alkyl group containing from 1 to 6 carbon atoms which may be substituted by OH, an N-phenyl group or an N-phenylalkyl group containing from 7 to 10 carbon atoms and their physiologically acceptable acid salts, quaternary ammonium salts and, when possible, anhydrides and basic salts, are prepared by numerous methods which involve the introduction or interconversion of the groups R 1  to R 8  and A by standard methods, optionally followed by resolution. Pharmaceutical compositions having antiinflammatory, antipyretic, analgesic activity comprise an above novel compound and a carrier or diluent therefor and are in forms suitable for enteral, parenteral or topical application. 3 - Methyl - 4 - amino - phenylacetic acid by hydrogenation of 3-methyl-4-nitro-benzyl cyanide and hydrolysis of resulting 2-methyl-4- amino-benzyl cyanide. 3 - Chloro - 4 - amino - phenylacetic acid by chlorination of 4-acetamido-benzyl cyanide and hydrolysis of resulting 3-chloro-4:-acetamidobenzyl cyanide. Methyl 3 - nitro - 4 - amino - phenylacetate by esterification of the free acid. 4 - Amino - α - methyl - phenylacetic acid and the corresponding 3-chloro compound are prepared by the hydrolysis of the required benzyl cyanides. 3 - Trifluoromethyl - 4 - piperidino - α,α - dimethylbenzyl cyanide by the reaction of 2-bromo- 5-nitrotrifluoromethyl-benzene with piperidine, the reduction of the corresponding 2-piperidino compound, diazotization of the resulting 2- piperidino - 5 - amino - trifluoromethyl - benzene, conversion to 2 - piperidino - 5 - cyano - trifluoromethyl-benzene, hydrolysis to 3-trifluoromethyl - 4 - -piperidinobenzoic acid, reduction to the corresponding benzyl alcohol, reaction with HBr to the benzyl bromide, conversion with KCN to 3 - trifluoromethyl - 4 - piperidinobenzyl cyanide and then hydrolysis. 3 - Fluoro - 4 - piperidino - acetophenone is prepared by the reaction of o-amino-fluorobenzene with 1,5-dibromopentane to form o-piperidino - fluoro - benzene and this compound is subjected to a Friedel Craft reaction with acetyl chloride. 3 - Fluoro - 4 - piperidino - # - chloroacetophenone by the reaction of 3-fluoro-4-piperidinoacetophenone and sulphuryl chloride. 3,#-Dichloro-4-piperidino-acetophenone is prepared by a similar method. 3 - Bromo - 4 - piperidino - phenyl - α - methyl malonic acid diethyl esters by the reaction of 3- bromo - 4 - piperidino - phenylacetic acid ethyl ester with diethyl oxalate followed by acid treatment and decarboxylation, and treatment of the resulting 3-bromo-4-piperidino-phenylmalonic acid diethyl esters with methyl iodide. In a similar manner, 4-piperidino-naphthyl-1- malonic acid diethyl ester and 4-piperidino-α- methyl-naphthyl-1-malonic acid diethyl ester and 2,3 - dichloro - 4 - piperidino - phenyl malonic acid diethyl ester and 2,3-dichloro-4-piperidinophenyl-α-methyl malonic acid diethyl ester. 3 - Chlorosulphonyl - 4 - piperidino - phenylacetic acid by oxidation of the corresponding 3- mercapto compound with chlorine and acetic acid. 3 - Nitro - 4 - (1<SP>1</SP> - pyridinium) - phenylacetic acid ethyl ester bromide by boiling 3- nitro-4-bromo-phenylacetic acid ethyl ester and pyridine. 3 - Methyl - 4 - piperidino - α - methylenephenylacetic acid ethyl ester by the reaction of o-toluidine and 1,5-dibromopentane, treatment of the resulting 2-piperidino-toluene with oxalyl chloride ethyl ester to form 3-methyl-4-piperidino - phenyl - glyoxylic acid ethyl ester, treatment of this compound with methyl magnesium iodide and heating the resulting 3,α-dimethyl-4- piperidino-mandelic acid ethyl ester with polyphosphoric acid. 3 - Methyl - 4 - piperidino - phenyl - glyoxylic acid by the hydrolysis of the corresponding ethyl ester. 2,3 - Dimethyl - 4 - piperidinophenyl-glyoxylic acid is prepared by a similar method. 3 - Methyl - 4 - piperidino - mandelic acid ethyl ester by the hydrogenation of 3-methyl-4- piperidino-phenyl glyoxylic acid ethyl ester. o - t - Butyl - N,N - dimethyl aniline by the alkylation of o-t-butylaniline with methyl iodide. 3 - Iodo - 4 - piperidino - α - methyl - mandelic acid ethyl ester is prepared from o-piperidinoiodobenzene via 3 - iodo - 4 - piperidino - phenylglyoxylic acid ethyl ester. N - [2 - iodo - 4 - (α - carbethoxyethylidene)- 2,5 - cyclohexadienylidene]- piperidinium chloride is obtained as a by-product from the reaction of 3 - iodo - 4 - piperidino - α - methylmandelic acid with SO 2 Cl 2  and dry HCl. 3 - Halo - 4 - N(R 7 R 8 ) - α - methylbenzyl cyanides wherein R 7  and R 8  together represent an alkylene chain of 2 to 14 carbon atoms attaehed to the nitrogen atom (the said chain may be interrupted by an oxygen or sulphur atom) are prepared by reducing 4-nitro-α- methyl-benzyl cyanides to the corresponding 4- amino compounds, acylating to the corresponding 4-acetamido compounds, reacting with a halogen to form 3-halo-4-acetamido-αmethylbenzyl-cyanides, removing the acetamido radical and reacting the resulting 3-halo-4-amino-α- methyl-benzyl cyanides with Hal-R 7 R 8 -Hal. 2 - (3 - Bromo - 4 - piperidino - phenyl) - 2- propanol by esterification of 3-bromo-4-aminobenzoic acid, treatment of the resulting methyl ester with 1,5-dibromopentane and reaction of the resulting 3-bromo-4-piperidino-benzoic acid methyl ester with methyl magnesium iodide. 3 - Methyl - 4 - piperidino - α - chlorophenylacetic acid ethyl ester hydrochloride is prepared by hydrogenating 3-methyl-4-piperidino-phenyl glyoxylic acid ethyl ester and treating the resulting 3 - methyl - 4 - piperidino - mandelic acid ethyl ester with thionyl chloride. By the last step, 3,α - dimethyl - 4 - piperidino - α- chloro-phenylacetic acid ethyl ester hydrochloride is obtainable from the corresponding chlorine free compound. 3 - Chloro - 4 - piperidino - α - methylbenzyl cyanide is prepared by treating the corresponding phenyl-acetamide with phosphorus oxychloride. 3 - Chloro - 4 - piperidino - α - methylphenylacetic acid 2<SP>1</SP>-chloroethyl ester by treating the required acetamide with 2-chloroethanol and HCl. 3 - Chloro - 4 - amino - naphthyl - 1 - acetic acid by the chlorination of 4-acetamidonaphthyl-1- acetic acid to form the corresponding 3-chlorocompound and hydrolysis of the 4-acetamido group in the latter compound. 2 - Methyl - 4 - amino - naphthyl - 1 - acetic acid is prepared by the reduction of the corresponding 4-nitro compound. 4 - Amino - α - methyl - naphthyl - 1 - acetic acid is prepared by the catalytic reduction and hydrolytic decarboxylation of 4-nitro-α-methylnaphthyl-1-malonic acid diethyl ester. By a similar method 4 -piperidino -α- methylenenaphthyl-1-acetic acid ethyl ester is obtained from 1 - naphthylamine via 1 - piperidino - naphthalene, 4 - piperidinonaphthyl - 1 - glyoxylic acid ethyl ester and 4-piperidino-α-hydroxy-α-methylnaphthyl - 1 - acetic acid ethyl ester, and 2,3 - di - chloro - 4 - piperidino - α - methylene - phenylacetic acid methyl ester is obtained from 2,3-dichloroaniline via 2,3-dichloropiperidinobenzene, 2,3 - dichloro - 4 - piperidino - phenylglyoxylic acid ethyl ester and 2,3-dichloro-4- piperidino - α - methyl - mandelic acid ethyl ester. 4 - Bromo - 3 - nitro - α - methyl - naphthyl - 1- acetic acid is prepared by nitration of the corresponding 3-unsubstituted compound or by nitration of 4-acetamido-α-methyl-naphthyl-1- acetic acid followed by hydrolysis, diazotization and reaction with cuprous bromide. 4 - Piperidino - naphthyl - 1 - acetonitrile is obtained from 1 -nitro-4-bromo-naphthalene via 1 - nitro - 4 - piperidino - naphthalene and the corresponding 1-amino- and 1-cyano compounds, 4 - piperidino - 1 - naphthoic acid, and 1- bromomethyl - 4 - piperidino - naphthalene. 4 - Piperidino - naphthyl - 1 - glyoxylic acid by acylation of 1-piperidino-naphthalene with exthoxalyl chloride in the presence of aluminium chloride followed by hydroly