Preparation and reductive decomposition of 2-iodoxybenzenesulfonic acid. X-ray crystal structure of 1-hydroxy-1H-1,2,3-benziodoxathiole 3,3-dioxide

2-Iodoxybenzenesulfonic acid (in a cyclic tautomeric form of 1-hydroxy-1H-1,2,3-benziodoxathiole 1,3,3-trioxide), a thiaanalog of 2-iodoxybenzoic acid (IBX) and a potentially important oxidizing reagent, was prepared by two different pathways: direct oxidation of 2-iodobenzenesulfonic acid and hydrolysis of the methyl ester of 2-iodylbenzenesulfonic acid. The resulting 1-hydroxy-1H-1,2,3-benziodoxathiole 1,3,3-trioxide was found to be thermally unstable and highly reactive towards organic solvents. The structure of its reductive decomposition product, 1-hydroxy-1H-1,2,3-benziodoxathiole 3,3-dioxide (the cyclic tautomeric form of 2-iodosylbenzenesulfonic acid), was established by single-crystal X-ray diffraction.