Synthesis and antimicrobial activities of novel formazans incorporating pyrimidine ring

Reaction of 5-substituted-4(3H)-one-2-mercaptopyrimidines 1a and 1b with hydrazine hydrate furnishes 5-substituted-4(3H)-one-2-hydrazinopyrimidines 2a and 2b. Condensation of compounds 2a and 2b with salicylaldehyde and anisaldehyde yields 2-hydroxybenzaldehyde-(5'-substituted-4'(3'H)-one)-2'-pyrimidazolylhydrazones) 3a and 3b and 4-methoxybenzaldehyde-(5'-substituted-4'(3'H)-one)-2'-pyrimidazolylhydrazones) 3c and 3d respectively. Compounds 3a-d were reacted with diazonium salts of an appropriate primary amine in presence of base furnished the target formazans 4a-1. All the synthesized compounds were evaluated for antimicrobial activities.