GB1361441A — Benzonaphthyridine derivatives

USPTO Abstract

1361441 Benzo-naphthyridine derivatives SANDOZ Ltd 10 May 1971 [13 May 1970 (2)] 13984/71 Heading C2C Novel 4a,10b-cis benzonaphthyridines of the formula wherein R 1 is hydrogen C 1-3 alkyl, alkoxy or alkythio, fluorine, bromine, chlorine, nitro, trifluoromethyl, amino or C 2-4 amido; R 2 is hydrogen, chlorine or C 1-3 alkyl or alkoxy; R 3 and R 4 are either both hydrogen or methoxy or together are methylene dioxy may be prepared by cyclizing a 3,4 cis-substituted compound II wherein R<SP>1</SP> 1 is as R 1 above excluding amino and C 2-4 amido, with an acidic water-removing condensation agent and optionally reducing this product in which R<SP>1</SP> 1 is nitro to amino at R 1 and thereafter optionally acylating this product to produce C 2-4 amido at R 1 . The novel compounds cis - 1,2,3,4,4a,10b - hexahydro - 8,9- dimethoxy - 2 - methyl - 6 - phenyl - benzo[c]- [1,6]naphthyridine and cis - 6 - (4 - acetamidophenyl) - 1,2,3,4,4a, 10b - hexahydro - 8,9- dimethoxy - 2 - methyl - benzo[c][1,6]naphthyridine and pharmaceutical compositions thereof are claimed in the divisional Specification 1,361,442. The intermediate II may be prepared by condensing an appropriate cis -4-amino-3-phenyl- 1-methyl piperidine with an appropriate benzoyl halide. Pharmaceutical compositions of the compounds I or salts thereof inhibit blood platelet aggregation when administered with a diluent or carrier.