Convenient synthesis and antibacterial activity of novel 5-phenyldiazenyl-1,3,4-thiadiazole derivatives

Abstract

Reaction of N,2-diaryldiazene-1-carbohydrazonoyl chlorides 1, 2 with 2-((methylthio)-carbonthioyl)hydrazones 7, 12 and 18–21 in absolute ethanol at room temperature in the presence of triethylamine afforded the corresponding 1,3,4-thiadiazole derivatives 10, 11, 13, 14 and 22–29. Stirring of N,2-diaryldiazene-1-carbohydrazonoyl chlorides 1–3 with thioanilides 31A–E in acetonitrile at room temperature in the presence of triethylamine gave the corresponding 1,3,4-thiadiazol-2(3H)-ylidene derivatives 34–36. The structures of all new compounds 10, 11, 13, 14, 22–29 and 34–36 were identified by elemental analysis and spectral data. Some new synthesized compounds were studied against Staphylococcus aureus and Escherichia coli and the most potent compounds were 3-phenyl-5-(phenyldiazenyl)-2-((1-(pyridin-2-yl)ethylidene)hydrazono)-2,3-dihydro-1,3,4-thiadiazole (13c), 2-((1-(pyridin-2-yl)ethylidene)hydrazono)-3-(p-tolyl)-5-(p-tolyldiazenyl)-2,3-dihydro-1,3,4-thia-diazole (14c) and 2-(benzo[d]thiazol-2-yl)-2-(3-(p-tolyl)-5-(p-tolyldiazenyl)-1,3,4-thiadiazol-2(3H)-ylidene)-acetonitrile (35C).

Graphical Abstract

Keywords:

• Chloroformazans
• methyl hydrazinecarbodithioate
• cycloaddition reaction
• thioanilides
• nitrileimines and antimicrobial activity