Synthesis and antimicrobial activities of condensed and uncondensed 1,2,4-triazines

Reaction of 3-hydrazino-5,6-diphenyl-1,2,4-triazine 1 with methyl phenylgly oxylate gave 3,6,7-triphenyl-1,2,4-triazolo[4,3-b] 1,2,4-triazine 3. Cycloc ondensation with pyruvic acid, ethyl pyruvate or diethyl oxalate afforded t he corresponding 3-substituted-4-oxo-7,8-diphenyl-1,2,4-triazino[4,3-b] 1,2 ,4-triazines 8a,b. Several 3-(pyrazol-1-yl)-5,6-diphenyl-1,2,4-triazines 10 a-c were prepared by reaction with 1,3-dicarbonyl compounds or acetylenic e sters. The hydrazone intermediates of some of these reactions were isolated and characterized. Compounds 2 6a,b, 7, 9a,b, and 10a,c showed no antibact erial activity against Escherichia coli and weak to moderate inhibitory act ivity against Bacillus subtilis and Staphylococcus aureus. Only compound 6a which showed weak antifungal activity against Candida albicans.