Thiolactone

Thiolactones are a class of heterocyclic compounds in organic chemistry. They are analogs of the more common lactones in which an oxygen atom is replaced with a sulfur atom. The sulfur atom is within the ring system and adjacent to a carbonyl group.

α-, β-, γ-, and δ-lactones (left to right)

Chemistry

Thiolactones can be prepared by dehydration of thiol-containing carboxylic acids. Thiolactones can be hydrolyzed back to the thiol acids under basic conditions.^[1] β-Thiolactones can be opened by reaction at the 4-position via S_N2 nucleophilic reactions.^[2]

Occurrence

The activation of the drug clopidogrel (top left) gives a thiolactone, which ring-opens.^[3]

Thiolactones are intermediates in the activation of some drugs.^[4]

In nature, the most common thiolactone is homocysteine thiolactone. It is produced from homocysteine. It may play a role in protein damage.^[5] The drugs citiolone and erdosteine are modified versions of homocysteine thiolactone.

Thiolactones have been found in peptides synthesized by bacteria such as Staphylococcus aureus in order to regulate their quorum-sensing system.^[6]

See also

• Lactone
• Lactam