Novel three component synthesis of 1,2,4-triazolo[3,4-b]thiazoles and their antimicrobial activity

1,2,4-Triazolo[3,4-b]thiazole derivatives 5a-j have been synthesized by novel multi-component reaction of 2,4-dichloro-5-fluorophenacyl bromide (1), thiosemicarbazide (2), and aromatic carboxylic acids (4) using phosphorous oxychloride as the cyclizing agent. This reaction protocol is simple, efficient, and requires shorter reaction times in comparison to the conventional multi-step synthesis. The products were identified to be same by an alternate synthesis. All the compounds were screened for their antimicrobial activity against some of bacterial and fungal strains.