GB1465661A — Stilbene derivatives

USPTO Abstract

1465661 Stilbene derivatives TAISHO PHARMACEUTICAL CO Ltd 13 June 1975 [16 July 1974] 25390/75 Heading C2C Novel compounds I in which each of R 1 and R 2 is H, C 1-5 alkyl, C 1-5 alkoxy, halogen or C 1-5 haloalkyl and each of R 3 and R 4 is H or C 1-5 alkyl, and salts thereof, are prepared by hydrolysis of a compound II or III in which B is amino, preferably, cyclic amino, or hydrolysis and decarboxylation of a compound IV in which R 3 is C 1-5 alkyl and A is alkyl, followed, if desired, by esterification of the free acid or an anhydride or halide derivative thereof. The esters in which R 3 is C 1-5 alkyl may also be prepared by alkylation of 3-stilbeneacetic acid esters. The salts are prepared in known manner. Compounds II are prepared by cyanation of compounds V which are themselves prepared by halogenation of compounds VI or VII Compounds II may also be prepared by a Meerwein arylation followed by an optional alkylation step. Compounds VII are prepared by reduction of compounds VIII. Compounds VI and VIII are prepared by means of a Meerwein arylation process. Compounds III are prepared from compounds VIII by a Willgerodt reaction. Compounds IV are prepared by reacting an appropriate alkyl 3-stilbeneacetate with a dialkylcarbonate and alkylating the resulting dialkyl 3-styrylphenylmalonate. Pharmaceutical compositions having analgesic and anti-inflammatory activity comprise one of the above novel compounds together with a pharmaceutical carrier.