Tandem Protocol for the Synthesis of 3-Acyl Benzothiadiazine 1,1-Dioxides

摘要

A metal-free and efficient tandem synthesis of 3-acyl 3,4- dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxides and 3-acyl-2H- 1,2,4-benzothiadiazine-1,1-dioxides has been developed via C-H functionalization of ethynylarenes and ethenylarenes followed by condensation with 2-aminobenzenesulfonamide. The reaction involves the formation of arylglyoxal as an intermediate from multiform substrates through Kornblum oxidation in the presence of iodine and DMSO. Use of simple and readily available starting materials, inexpensive reagent, broad substrate scope and a very simple operation are noteworthy features of this protocol. This method provides an easy access to pharmaceutically important 3-acyl-1,2,4-benzothiadiazine- 1,1-dioxides in good yields.