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 benzo[ d ]thiazol‐5‐amine in HOAc under microwave irradiation has been developed. A series of new thiazolo‐fused benzo[ h ]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 oxazolo[5,4‐ a ]thiazolo[5,4‐ 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.