Microwave-assisted green synthesis of new imidazo[2,1-b]thiazole derivatives and their antimicrobial, antimalarial, and antitubercular activities

Abstract

We have synthesized some imidazo[2,1-b]thiazole derivatives by reaction of 1-(2-amino-4-methylthiazol-5-yl)ethanone or ethyl 2-amino-4-methylthiazole-5-carboxylate with α-bromo aralkyl ketones (phenacyl bromides) in presence of polyethylene glycol-400 (PEG-400) as efficient, inexpensive, biodegradable, and green reaction medium and catalyst (dual nature) under Microwave Irradiation (MWI) at 300 W as well as under thermal heating at 90 °C. Moreover, we also synthesized 1-(2-amino-4-methylthiazol-5-yl)ethanone and ethyl 2-amino-4-methylthiazole-5-carboxylate by one-pot reaction of acetyl acetone/ethyl acetoacetate with N-bromosuccinimide (NBS) and thiourea in presence of PEG-400 under microwave irradiation at 180 W. All synthesized compounds were screened for antimicrobial and antimalarial activities. All compounds were found to show good to excellent antibacterial activity, and some analogs exhibited good antimalarial activity.