2-Hetaryl derivatives of 3-oxo-3,4-dihydro-2H-1,4-benzothiazine

A new approach for the synthesis of 2-hetaryl derivatives of 3-oxo-3,4-dihydro-2H-1,4-benzothiazines is described. 2-Chloro derivatives of 2a,b were reacted with electron-rich heterocycles 3-14 under basic catalysis (witha slight excess of Et 3 N) to provide the substitution products 16-36. In the reaction of 2b with 14 and 15, an intermolecular cyclization took place between the amino and ethoxycarhonyl groups, resulting in spiro compounds 35 and 36, respectively.