GB1413042A - Phenylalkenoic acid derivatives - Google Patents

Abstract

1413042 trans-Phenylalkenoic acid derivatives DR KARL THOMAE GmbH 7 Feb 1973 [8 Feb 1972 15 May 1972] 6071/73 Heading C2C [Also in Division A5] Novel trans-phenylalkenoic acid derivatives of the general formula wherein R 1 is a phenyl group (optionally substituted by one or two halogen atoms or by a nitro or cyano group or by an amino group, optionally substituted by C 1-4 aliphatic acyl group) or a C 1-7 alkyl, C 5-7 cycloalkyl, C 5-7 cycloalkenyl or piperidino group; R 3 is a hydrogen or halogen atom or additionally, where R 1 is other than a substituted or unsubstituted phenyl group, a nitro, amino or cyano group, with the proviso that R 3 is not a hydrogen atom where R 1 is an unsubstituted phenyl group; A is a -C(R 2 ) = CH-CH 2 - or -CH(R 2 )-CH = CH- group, where R 2 is a hydrogen atom or a methyl or ethyl group; and B is a hydroxyl, C 1-4 alkoxy or -NR 4 R 5 group, where, when R 1 is an optionally substituted phenyl group, each of R 4 and R 5 is a hydrogen atom or C 1-3 alkyl group or R 4 is a hydroxyphenyl group and R 5 is a hydrogen atom, and, when R 1 is other than an optionally substituted phenyl group, each of R 4 and R 5 is a hydrogen atom, and salts thereof are prepared (a) when B is a hydroxy group, by heating a compound of the general formula in the presence of a hydrohalic acid addition salt of a tertiary organic base; (b) when each of R 1 and R 3 is not or does not contain a nitro or cyano group, A is a -CH=CH-CH 2 - or -CH 2 - CH = CH-group and B is a hydroxy group, by reacting a compound of the general formula wherein each of R 1 and R 3 is not or does not contain a cyano group, with zinc or amalgamated zinc and an acid; (c) when B is a hydroxy group, by reacting a compound of the general formula with malonic acid or a mono- or di-ester thereof in the presence of an acid or slightly basic catalyst, followed by saponification and decarboxylation (if a mono- or di-ester is used) or by decarboxylation (if the acid is used); (d) when B is an -NR 4 R 5 group, by reacting the corresponding compound in which B is a halogen atom or an alkoxy group with a compound of the general formula HNR 4 R 5 ; (e) when R 1 is an aminophenyl group, by alkaline hydrolysis of the corresponding compound in which R 1 is an acylaminophenyl group; (f) when B is an alkoxy group, by esterifying the corresponding free acid; and (g) when A is a -C(R 2 ) = CH-CH 2 - group and B is a hydroxy group, by isomerization of the corresponding compound in which A is a -CH(R<SP>2</SP>)-CH = CH- group by heating in the presence of a base; followed by separation of the desired trans isomer and optionally by salification of a resulting compound having a free base or acid group. 2 - (2<SP>1</SP> - Fluoro - 4 - biphenylyl) - propionaldehyde is prepared by reacting 4-acetyl-2<SP>1</SP>-fluorobiphenyl with trimethylsulphonium iodide in the presence of potassium methylate and isomerizing the resulting 2-(2<SP>1</SP> fluoro-4-biphenylyl)- 2-methyl-oxirane in the presence of BF 3 etherate.