thiolide

A thiolide is a cyclic ester of a thiol and a carboxylic acid. It is also known as a thiolactone. The structure consists of a sulfur atom within a ring, bonded to a carbonyl group. The ring size can vary, with common examples including five-membered and six-membered thiolides. Thiolides are formed through intramolecular cyclization reactions. Typically, a molecule containing both a thiol (-SH) group and a carboxylic acid (-COOH) group undergoes dehydration, leading to the formation of the cyclic ester and water.

These compounds are found in nature and also synthesized in laboratories. Some natural thiolides possess biological activity, acting as enzyme inhibitors or signaling molecules. In organic synthesis, thiolides serve as intermediates in the preparation of various compounds, including polymers and pharmaceuticals. Their reactivity is influenced by the ring strain and the nature of the substituents. Hydrolysis of a thiolide will regenerate the parent thiol and carboxylic acid. Thiolides can undergo ring-opening polymerization under certain conditions, forming poly(thioester)s. The sulfur atom in the thiolide ring can also participate in nucleophilic or electrophilic reactions.