Synthesis and Rate of Hydrolysis of an Aromatic Sulfinic Anhydride: Benzene-o-disulfinic Anhydride

Article abstract of DOI:10.1021/jo00326a018

The compound previously (ref 4) thought to be benzene-o-disulfinic acid (6) has been shown to be, in fact, the corresponding sulfinic anhydride, 7, the first reported example of an aryl sulfinic anhydride.The kinetics of the hydrolysis of 7 in aqueous dioxane has been determined and compared with those for the hydrolyses of two aromatic sulfinyl sulfones, 8 and 9.Sulfinic anhydride 7 hydrolyzes 4000 times faster than 8 and 200 times faster than 9; ΔH(excit.) for its hydrolysis is 6 kcal/mol less than that for 9.The significantly lower ΔH(ecit.) for the sulfinic anhydride is consistent with other indicators, suggesting that sulfinic anhydrides are normally substantially less stable thermodynamically than the isomeric sulfinyl sulfones.