Tr. Mihova et al., Ring enlargement of eight- and nine-membered cyclic sulfonamide derivatives in reactions with 3-amino-2H-azirines, HETEROCYCLE, 49, 1998, pp. 215-232
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 g
ave the correspondingly substituted 3-dimethylamino-4,5,6,7,8,9-hexahydrobe
nzo-1-thia-2,5-diazacycloundecen-6-one 1,1-dioxides (8). In the case of the
reaction of 1a with 6a, the 3-amino5,6-dihydro-4H-benzothiazocine 1,1-diox
ide derivative (9) was termed as a minor product. The structures of the sta
rting material (6a), the unexpected 4,5-dimethoxy-2-(3-cyanopropyl)benzenes
ulfonyl 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 enlarg
ed twelve-membered heterocycle (10).