Stereoselective one-pot synthesis of substituted (4Z)-2-alkyl-4-benzylidene- 4H-1,3-benzothiazines.

Substituted (4Z)-4-benzylidene-2-methyl-4H-1,3-benzothiazines (1). and (4Z)-2-ethyl-4-benzylidene-4H-1,3-benzothiazines (2). were synthesized by direct stereoselective reactions of S-phenyl ethanethioate or S-phenyl propanethioate with substituted benzyl nitriles in the presence of triflic anhydride.