DBU catalysis in micellar medium: an environmentally benign synthetic approach for triheterocyclic 4H-pyrimido[2,1-b]benzothiazole derivatives

Abstract

An efficient, simple, practical and scalable approach for the preparation of pharmaceutically important scaffold 4H-pyrimido[2,1-b]benzothiazoles using one-flask three-component cyclo-condensation of β-ketoester, substituted aromatic aldehydes and 2-aminobenzothiazole under micellar medium as an environmentally benign protocol is reported. The reaction is catalyzed by DBU and CPB as a green, easily available, cheap and sustainable catalyst. The product formation takes shorter duration with good to excellent yield of the products. The method is also demonstrated on multi-gram level. The Atom economy, environmentally benign, easy to work-up, no use of hazardous solvents, short reaction time are the most outstanding advantages of the developed methodology.