Bis[1,2]dithiolo[3,4-b][4′,3′-e][1,4]thiazine-3,5-dione, a planar 1,4-thiazine

Abstract

N-Benzyldiisopropylamine 1 and S2Cl2 give the N-benzylbisdithiolothiazine 2, shown by X-ray crystallography to have the typically folded tricyclic structure; 2 is debenzylated by H2SO4 to give the title compound 4 which atypically has a rare near-planar 1,4-thiazine ring, gives a blue anion in solution and does not extrude sulfur thermally.