Pyrimido-1, 4-benzothiazines and -1, 4-benzothiazepines. I. Oxidative Coupling and Pummerer Rearrangement of Pyrimido-1, 4-benzothiazine and Its Sulfoxide

Abstract

Pyrimido-(1, 4)-benzothiazinedione (I) underwent oxidative coupling with water, alcohols and morpholine at the 4α-angular position in the presence of iodine and base such as triethylamine or morpholine. The facile Pummerer rearrangement of its sulfoxide also give 4α-substituted derivatives. The mechanisms of these reaction are also discussed.