Tetrazoles are doubly unsaturated five-membered aromatic heterocycles consisting of one carbon atom and four nitrogen atoms. Tetrazole derivatives are a major class of heterocyclic compounds that are important for medicinal chemistry and drug design because of their not only isosteric properties with carboxylic acid and amide moieties, but also metabolic stability and other beneficial physicochemical properties.
Thiane is a heterocyclic compound and an organosulfur compound with the formula (CH2)5S. It is a saturated six-membered ring containing five carbon atoms and one sulfur atom.