Organoiodine (III) mediated synthesis of 3-aryl/hetryl-5,7-dimethyl-1,2,4-triazolo[4,3-a]pyrimidines as antibacterial agents

Synthesis of some new 3-aryl/hetryl-5.7-dimethyl-1,2,4-triazolo[4.3-a]pyrimidines (3a-k) has been accomplished by the oxidation of 4,6-dimethyl-2-pyrimidinylhydrazones of various aldehydes with iodobenzene diacetate in dichloromethane. Nine new compounds (3b-g and 3i-k) were tested in vitro for their antibacterial activity. Two compounds. namely 3-(4'-pyridyl)-5,7-dinethyl-1,2,4-triazolo[4,3-a] pyrimidine (3k) and 3-(3'.4'-dimethoxvphenyl)-5,7-dimethyl-1,2,4-triazolo[4,3-a]pyrimidine (3f), were associated with substantially higher antibacterial activity than some commercial antibiotics against Bacillus subtilis, Escherichia coli, Staphlococcus aureus and Salmonella typhi at MIC (minimum inhibitory concentration) i.e. 10 mug/ml. (C) 2004 Elsevier SAS. All rights reserved.