[Research on substances with psychotropic activity. IV. Synthesis of 2,3-diphenyl-4-methyl-4H-1,4-benzothiazin-1,1-dioxide by thermal cyclization of N-(2-desylsolfonylphenyl) glycine].

Treatment of the ethyl ester of N-benzoyl-N-(2-benzylsolfonylphenyl)glycine with potassium in benzene gave, by rearrangement, N-(2-desylsolfonylphenyl)glycine, which via thermal intramolecular cyclization and simultaneous decarboxylation gave 2,3-diphenyl-4-methyl-4H-1,4-benzothiazin-1,1-dioxide. The structure of the latter compound was confirmed chemically by oxidising the known 2,3-diphenyl-4-methyl-4H-1,4-benzothiazine with hydrogen peroxide in formic acid and by I;R. and N.M,R; spectral data.