Synthesis and antibacterial activity of 6-aryl-3-(2′-methyl-1′, 8′-naphthyridin-3′-yl)-1, 2, 4-triazolo-[3,4-b][1,3,4]thiadiazoles

2-Methyl-1, 8-naphthyridine-3-carboxylic acid hydrazide 2 on reaction with CS₂ in the presence of KOH affords 5-mercapto-2-(2′-methyl-1′, 8′-naphthyridin-3′-yl)-1, 3, 4-oxadiazole 3, which is converted into 4-amino-5-mercapto-3-(2′-methyl-1′, 8′-naphthyridin-3′-yl)-1, 2, 4-triazole 4 by the reaction with hydrazine hydrate. Cyclization of 4 with aromatic acids in refluxing POCl₃ yields 6-aryl-3-(2′-methyl-1′, 8′-naphthyridin-3′-yl)-1, 2, 4-triazolo[3, 4-b][1, 3, 4]thiadiazoles 5. Compounds 5 have been tested for their antibacterial activity.