Three‐Component Synthesis of Fluorescent 1,4‐Benzothiazin‐2‐ones through Thiol‐Free Iodine‐Catalyzed Cyclization

A convergent synthesis of 2H‐benzo[b][1,4]thiazin‐2‐one was achieved via iodine‐catalyzed three‐component reaction. This strategy involves the formation of two new C–S bonds and a C–N bond from the readily available precursors ‐ aryl methyl ketones, p‐anisidine, and elemental sulfur to generate the desired heterocycle in moderate to good yields. As the synthesized benzothiazine‐2‐ones are fluorescent under UV light, photophysical properties like solid‐state emission, solvatochromism, Aggregation Induced Emission (AIE), and the relative quantum yields of the compounds were measured which proves them to be a potential candidate for the development of optoelectronic devices.