Synthesis and antibacterial evaluation of novel hydrazones and bis-hydrazones containing 1,2,3-triazole moiety

The current work reports the synthesis of novel hydrazones and bis-hydrazones containing 1,2,3-triazole moiety. Base-assisted aldol condensation of 4-acetyl-1,2,3-triazole 1a (R = NO2) and anisaldehyde (2) gave the corresponding chalcone 3 in 88% yield. 4-(1-(2-(2,4-Dinitrophenyl)hydrazineylidene)-3-(4-methoxyphenyl)allyl)-5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazole (5) was synthesized in 85% yield from the reaction of 3 and 2,4-dinitrophenylhydrazine (4) in boiling ethanol in the presence of a catalytic amount of HCl. Condensation of 1b (R = OMe) and N-phenylhydrazinecarbothioamide(6) in an acidic medium led to unexpected bis-hydrazones 8 rather than carbothioamide 7. An acid catalyzed one-pot three-component reaction of carbohydrazide 9, isatoic anhydride (10), and 1b,c (c: R = F, d: R = H) gave the corresponding hydrazones 12a-12c in high yields, instead of the expected dihydroquinazolin-4(1H)-ones 11. The resulting hydrazones were fully characterized using different techniques including H-1 NMR, C-13 NMR, X-ray and elemental analysis. Antibacterial screening revealed that some of the synthesized heterocycles showed moderate activity against Staphylococcus aureus ATCC-47077 and Listeria monocytogenes ATCC-35152.