Thiophene is a five-membered heterocyclic compound containing a sulfur heteroatom with the molecular formula C4H4S. Thiophene is aromatic and is very similar to benzene; electrophilic substitution reaction is easier than benzene, and it is mainly substituted at the 2-position. Thiophene ring system has certain stability to oxidant.
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.