A simple, facile and greener route to thiazolo[3,2-c]pyrimidinones in semi-aqueous medium and their antibacterial properties

By using easily accessible heterocyclic enamines, acetaldehyde (or formaldehyde) and primary amines as suitable precursors, a water-assisted three-component synthesis of new 3-oxothiazolo[3,2-c]pyridimines has been efficiently achieved in mild and semi-aqueous medium. All the cyclization reactions under optimized and catalyst-free conditions furnish the target compounds in 40–100% yields. Although cyclizations with arylamines in the presence of formaldehyde yield moderate to good yields, certain cyclizations involving aryl amines in the presence of acetaldehyde do not result in any product formation. Structural characterization of all the products were performed by means of FT-IR,¹H and ¹³C NMR and HRMS analyses. Besides, some of the products demonstrated bacteriostatic effects in the antibacterial study conducted against S. aureus and S. epidermidis bacteria.