thiolactone

A thiolactone is a cyclic thioester. It is formed when a thiol group (-SH) reacts with a carboxylic acid group (-COOH) within the same molecule to form a six-membered ring. The sulfur atom is incorporated into the ester linkage, replacing the oxygen atom found in a lactone. The general structure of a thiolactone is a ring containing a sulfur atom bonded to a carbonyl group, with the sulfur also being part of a carbon chain that closes the ring.

Thiolactones are generally more reactive than their lactone counterparts due to the weaker carbon-sulfur bond compared to the carbon-oxygen bond. This increased reactivity makes them useful intermediates in organic synthesis. They can undergo nucleophilic attack at the carbonyl carbon, leading to ring opening. This reaction can be used to introduce thiol or thioether functionalities into other molecules.

Thiolactones can be synthesized through various methods, often involving intramolecular cyclization reactions. One common approach is the cyclization of 4-mercaptopropanoic acid derivatives. The properties and stability of thiolactones can vary depending on the size of the ring and the substituents present. They are encountered in some natural products and have found applications in medicinal chemistry and materials science.