Base-promoted cyclization reaction of o -isothiocyanato arylacetylenes and aroylacetonitriles: easy access to benzo[ d ][1,3]thiazines.

A green and efficient synthesis of benzo[ d ][1,3]thiazines through a base-promoted cyclization reaction of o -isothiocyanato arylacetylenes with aroylacetonitriles has been developed. This protocol features high step economy and efficiency, and tolerates various functional groups. The reaction was scalable and applied for the post-modification of drugs.