Solid-phase synthesis of 2-substituted-3-(substituted sulfanyl)-1,2,4-benzothiadiazine 1,1-dioxide library

The first solid-phase synthesis of 2-substituted-3-(substituted sulfanyl)-1,2,4-benzothiadiazine 1,1-dioxides has been developed. Synthesis of the title compounds was achieved as follows: (1) sulfonylation of solid-supported primary amines with 2-nitrobenzenesulfonylchlorides, (2) reduction of the nitro group, (3) cyclization with thiocarbonyldiimidazole (formation of thiourea), (4) S-alkylation or S-arylation of the thiourea. In addition to the excellent purity of the product, a large-size library can be synthesized with the method as this synthesis includes three diversity points.