SYNTHESIS OF 1,2-BENZISOTHIAZOLES BY THE OXIDATIVE RING CONTRACTION OF 2-ARYL- AND 4-ARYL-3,4-DIHYDRO-2H-1,3-BENZOTHIAZINES

Article abstract of DOI:10.1016/S0040-4020(01)80102-2

Sodium periodate oxidation of 6,7-dimethoxy-2-aryl-3,4-dihydro-2H-1,3-benzothiazines (1a-e) gave 5,6-dimethoxy-1,2-benzisothiazole (4).The N-substituted analogues (6a-c) and the 4-aryl isomers of the latter (11a,b) furnished 2-substituted 1,2-benzisothiaz