Iron-catalyzed microwave-promoted expeditious one-pot synthesis of benzo[b][1,4]thiazine-4-carbonitrile under solvent-free condition

A highly efficient one pot green synthesis of benzo[b][1,4]thiazine-4-carbonitrile has been achieved under solvent-free conditions by the reaction of 2-aminobenzothiazole with terminal alkynes using microwave irradiation in the presence of Iron(III)fluoride as a catalyst. The unique features of this environmentally benign protocol are use of inexpensive catalyst, short reaction time, a wide range of functional group tolerance, easy and quick isolation of products with good to excellent yields via a simple experimental and work-up procedure. The catalyst can be recovered and reused for at least three runs without any significant impact on product yields. (C) 2016 Elsevier Ltd. All rights reserved.