Abstract Reaction of five-membered ring anhydrides with sodium sulfide has previously been employed for synthesis of the corresponding thioanhydrides in low yields. Re- examination of the stoichiometry reveals reaction of cyclic anhydride with sodium sulfide (2: 1 respectively), affords the thioanhydride accompanied by the corresponding dicarboxylate in a 1: 1 molar ratio. The mechanistic pathway for this reaction has also been elucidated. ...
