One pot synthesis of [1,3]-oxazine and [1,3]-thiazine derivatives under thermal and microwave conditions

A simple and efficient synthesis of substituted benzo [1,3] oxazine and benzo [1,3] thiazine derivatives under conventional heating, as well as microwave irradiation is reported. The compounds were obtained by the reaction of electron rich phenols, formaldehyde, and aromatic amines in methanol. Reactions which take 12–16 hr under conventional heating were successfully completed within a few minutes under microwave irradiation (solventless) with moderate to excellent yields. J. Heterocyclic Chem., 2010.