Imidazolines are a class of heterocycles derived from imidazoles by reduction of one of the two double bonds. Three isomers are known, 2-imidazoline, 3-imidazoline and 4-imidazoline. 2 and 3-imidazolines contain imine centers, while 4-imidazolines contain alkene groups. The 2-imidazoline group occurs in several drugs. Imidazolines are an important class of compounds found in many natural and medicinal products. These compounds are also used as intermediates in the synthesis of organic molecules. Furthermore, chiral imidazolines are widely used as organic catalysts for the synthesis of various natural and synthetic organic compounds.
Thiazolines are a group of isomeric five-membered heterocyclic compounds containing both sulfur and nitrogen. Thiazoline exists in three isomeric forms namely 2-thiazoline, 3-thiazoline and 4-thiazoline. Oxazolines, oxazoles, thiazolines, and thiazoles form the characteristic heterocyclic building blocks of lissoclinum peptide alkaloids.