Pyridopyrimidines. Part-VII. Synthesis and Antibacterial Activity of 4-lminopyrido[2, 3 - d] pyrimidin- 2( 1 H)-thiones, 2-Thioxopyrido[2, 3 - d]pyrimidin-4(3H)-ones and related Compounds

Department of Chemistry, St. Xavier's College, Navarangpura, Ahmedabad-380 009 Manuscript received 27 December 1988, revised 23 June 1989, accepted 26 June 1989 2-Amino-3-cyano-4-(4-chlorophenyl)-6-phenylpyridine (I) and 2-amino·3·carboxamido-4-(4-chlorophenyl)·6-phenylpyridine (3) when reacted with various isothiocyanates, 4-amino-3·substituted-5-(4·chlorophenyl)-7·phenylpyrido[2,3-d]pyrimidin-2(1H)-thiones(2) and 2·thioxo-3-substituted-5-(4-chlorophenyl)-7-phenylpyrido[2,3-d]pyrimidin-4(3H)-ones (4) were obtained respectively. 4 on methylation afforded the 2-methylmercapto derivatives (5) which on reaction with morpholine/piperidine yielded 2-N-(morpholino/piperidino )-3 substituted·5-( 4-chlorophenyl)-7·phenylpyrido[2,3-d]pyrimidin-4( 3H )-ones (6). Some of the compounds have been tested for antibacterial activity