Ring Enlargement of Eight- and Nine-membered Cyclic Sulfonamide Derivatives in Reactions with 3-Amino-2H-azirines

Abstract

The reactions of 3-dimethylamino-2H-azirines (1) with 3,4,5,6-tetrahydro-8,9-dimethoxy-2H-1,2-benzothiazocin-3-one 1,1-dioxide (6a) in acetonitrile gave the correspondingly substituted 3-dimethylamino-4,5,6,7,8,9-hexahydrobenzo-1-thia-2,5-diazacycloundecen-6-one 1,1-dioxides (8). In the case of the reaction of 1a with 6a, the 3-amino-5,6-dihydro-4H-benzothiazocine 1,1-dioxide derivative (9) was formed as a minor product. The structures of the starting material (6a), the unexpected 4,5-dimethoxy-2-(3-cyanopropyl)benzenesulfonyl chloride (7), the novel eleven-membered heterocycles (8a,8c) and that of 9 were established by X-Ray crystallography. With the nine-membered homologue 2,3,4,5,6,7-hexahydro-9,10-dimethoxy-1,2-benzothiazonin-3-one 1,1-dioxide (6b), only the most reactive aminoazirine yielded the ring enlarged twelve-membered heterocycle (10).