Thiazine is an organic compound containing four carbon rings, one nitrogen atom and one sulfur atom. Thiazine has three isomers, 1,2-thiazine, 1,3-thiazine and 1,4-thiazine, which are arranged differently in the ring. Nitrogen-containing heterocyclic compounds such as 1,4-thiazine and its benzo derivatives are important compounds in many different research fields due to their remarkable biological properties.
When the ends of the chains are joined together into a ring, cyclic compounds result; such substances often are referred to as carbocyclic or alicyclic compounds. Substitution of one or more of the ring carbon atoms in the molecules of a carbocyclic compound with a heteroatom gives a heterocyclic compound.