Thiazine/ˈθaɪəziːn/ is an organic compound containing a ring of four carbon, one nitrogen and one sulfur atom. There are three isomers of thiazine, 1,2-thiazine, 1,3-thiazine, and 1,4-thiazine, which differ by the arrangement of the nitrogen and sulfur atoms in the ring.
^Barkenbus, Charles; Landis, Phillip S. (February 1948). "The Preparation of 1,4-Thiazine". Journal of the American Chemical Society. 70 (2): 684–685. doi:10.1021/ja01182a075. ISSN0002-7863.