Intramolecular sulphonamidomethylation. Part II. Fused heterocycles from 2-phenylethanesulphonamides

1,2,4,5-Tetrahydro-3,2-benzothiazepine 3,3-dioxides 2 , with a variety of substituents on the nitrogen atom, can be easily obtained by the title reaction. The isomeric compounds 4–6 are also formed from sulphonamides bearing an N-aralkyl group with a chain of two or more carbon atoms. Activation of the ring closure-position or deactivation of the aromatic ring in the substituent can direct the reaction to give compounds 2 . Cyclization results are influenced by the size of the new heterocycle ring and by the predominant formation of derivatives with the SO₂ group outside the ring.