Regioselectively Synthesis of Thiazolo[4,5‐a]acridines and Oxazolo[5,4‐a]thiazolo[5,4‐j]acridines via Multicomponent Domino Reactions

A regioselective three‐component reaction of aromatic aldehydes, 2‐hydroxy‐1,4‐naphthoquinone and benzod]thiazol‐5‐amine in HOAc under microwave irradiation has been developed. A series of new thiazolo‐fused benzoh]acridines were synthesized with high chemical yields in this one‐pot reaction. The resulting thiazolo‐fused acridines were employed to further react with aldehydes and ammonium acetate to give polycyclic‐fused oxazolo5,4‐a]thiazolo5,4‐j]acridines. The present synthesis shows several advantages, such as operational simplicity, fast reaction rates, which makes it a useful and attractive process of library generation for drug discovery.