Decarboxylation of isatoic anhydrides with disulfides: an efficient and general synthesis of S-aryl 2-aminobenzothioate derivatives

The decarboxylation of isatoic anhydrides with disulfides was realized in the presence of sodium dithionite, leading to S-aryl 2-aminobenzothioate derivatives in moderate to excellent yields. Furthermore, the decarboxylation of diphenyldiselenide with isatoic anhydrides was also examined. It was noted that unexpected 2-(dimethylamino)-4H-benzo[d][1,3]thiazin-4-one was obtained using tetramethylthiuram disulfide as sulfur source.