A RING-OPENING REACTION OF BENZISOTHIAZOLONES - A NEW ROUTE TO UNSYMMETRICAL DISULFIDES

A series of unsymmetrical disulfides has been prepared by employing a reaction involving a ring opening, nucleophilic attack of a thiol on a 1,2-benzisothiazol-3-one. The benzisothiazolones were in turn prepare d by an intramolecular ring closure of an amide on a sulfenyl thiocarb onate. The sulfenyl esters were synthesized as intermediates for prepa ring mixed-disulfides, but the benzisothiazolone ring closure occurred spontaneously. It was initially thought that the mixed-disulfides wer e being formed from the sulfenyl ester, but the isolation and stepwise reaction of the benzisothiazolones provided proof for the reaction me chanism.