Pyridopyrimidines. Part-VII. Synthesis and Antibacterial Activity of 4-Iminopyrido[2,3-d]pyrimidin-2(1H)-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-cyan-4-(4-chloropheny1)-6-phenylpyridine (1) and 2-amino-3-carboxami­do-4-(4-chloropheny1)-6-phenylpyridine (3) when reacted with various isothiocyanates, 4-imino-3-substituted-5-(4-chloropheny1)-7-phenylpyrido[2,3-d]pyrimidin-2(1H)-thiones(2) and 2-thioxo-3-substItuted-5-(4-chlorapheny1)-7-phenylpyrine [2,3-di pyri ars idin-4(3H)-enes (4) were obtained respectively. 4 on methylation afforded the 2-methylmercapto deriva­tives (5) which on reaction with morpholine/piperidine yielded 2-N-(morpbolino/piperi­dino)-3 substituted-5 -(4-chloropheny1)-7-phenylpyrido[2,3-d]pyrimidin-4( 3H )-ones (6). Some of the compounds have been tested for antibacterial activity.