Synthesis of various pharma based pyrido[2,3-d]pyrimidine as well as pyrido[1,2-a]pyrimidine and their antimicrobial activities

4-Ainino-7-{4'-[4 ''-methylpiperazinyl)diazenyl]phenyl}-5-(substitutedphenyl)-1H-pyrido[2,3-d)pyrimidine-2-one (4a-j), 4-amino-7-{4'-[(4 ''-methylpiperazinyl)diazenyl]phenyl}-5-(substitutedphenyl)-1H-pyrido[2,3-d]pyrimidine-2-thione (5a-j). 4-thioureido-7-{4'-[(4 ''-methylpiperazinyl)diazenyl]phenyl}-5-(substitutedphenyl)-1H-pyrido[2.3-d]pyrimidine-2-thione (6a-j), 2-methyl-7-{4'-[4 ''-methylpiperazinyl)diazenyl]phenyl}-5-(substitutedphenyl)-3H-pyrido[2,3-d]pyrimidine-4-one (7a-j) and 4-methyl-5-{4'-[(4 ''-methylpiperazinyl)diazenyl]phenyl}-2-oxo-7-(substitutedphenyl)-2H-pyrido[1,2-a]pyrimidine-8-carbonitrile (8a-j) have been synthesized by the reaction of 2-amino-6-{4'-[(4 ''-methylpiperazinyl)diazenyl]phenyl}-4-(substitutedphenyl)pyridine-3-carbonitrile (3) with urea, thiourea, ammonium thiocyanate, acetic anhydride and ethylacetoacetate respectively. These compounds have been screened for their antibacterial and antifungal activities against different microorganisms The structures of novel synthesized compounds have been established on the basis of elemental analysis. H-1 NMR and IR spectral data.