Thiolactone

As thiolactones refers to a group of sulfur - containing heterocyclic compounds in the organic chemistry. In thiolactones a sulfur atom is incorporated in a ring system which in addition to the adjacent carbon atom bearing a carbonyl group.

The thiolester bond of the ring system is thereby established between a mercapto ( thiohydroxy ) and a carboxyl group of the same molecule with the elimination of a water molecule. Thiolactones are to be regarded as an internal ( cyclic ) mercaptosubstituierter thiol carboxylic acids. Thus the thiolactones resemble the lactones, the inner esters are hydroxy-substituted carboxylic acids.

Occurrence, preparation and properties

While α - thiolactones known only as unstable intermediates and the β - thiolactones ( four rings ) are displayed only under special conditions, the γ - and δ - thiolactones the ( five- or six-membered rings ) easily representable and stable heterocyclic compounds. γ -Lactones can be obtained by evaporation of dilute aqueous solutions of the corresponding chain-like γ - mercaptocarboxylic acids. A known chiral thiolactone is homocysteine ​​thiolactone (IUPAC: 3- Aminothiolan -2-one ). By heating with aqueous hydroiodic acid methionine, the methyl group of methionine is cleaved. Evaporation occurs with elimination of water as the hydriodide cyclization of homocysteine ​​thiolactone.

Also during heating of mixtures of cystine and cysteine ​​to form various thiolactones. Homocysteinthiolactone are triggers of programmed cell death in cell cultures and cause chromosomal damage.