Dithiol

Upon heating, gem-dithiols often release hydrogen sulfide, giving the transient thioketone or thial, which typically convert to oligomers.

Ethane-1,2-dithiol reacts with aldehydes (−CH=O) and ketones (>C=O) to give 1,3-dithiolanes: Some dithiols are used in chelation therapy, i.e. the removal of heavy metal poisons.

When derived from aldehydes, the methyne (=CH−) group is sufficiently acidic that it can be deprotonated and the resulting anion can be C-alkylated.

[4] Like 1,2-ethanedithiol, propanedithiol forms complexes with metals, for example with triiron dodecacarbonyl: A naturally occurring 1,3-dithiol is dihydrolipoic acid.

[5] A common 1,4-dithiol is dithiothreitol (DTT), HSCH2CH(OH)CH(OH)CH2SH, sometimes called Cleland's reagent, for to reduce protein disulfide bonds.

Reduction of a typical disulfide bond by DTT via two sequential thiol-disulfide exchange reactions.