Dithiol
In
organosulfur compound with two thiol (−SH) functional groups. Their properties are generally similar to those of monothiols in terms of solubility, odor, and volatility
. They can be classified according to the relative location of the two thiol groups on the organic backbone.
- Structure of some dithiols
-
Benzene-1,2-dithiol, the parent aromatic dithiol -
-
The drug meso-2,3-dimercaptosuccinic acid -
Dimercaprol ("British anti-Lewisite"), an early antidote for arsenic poisoning -
Dihydrolipoic acid, a vitamin -
Dithiothreitol, a reagent in protein biochemistry
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Geminal dithiols
Geminal dithiols have the formula RR'C(SH)2. They are derived from aldehydes and ketones by the action of hydrogen sulfide. Their stability contrasts with the rarity of geminal diols. Examples include methanedithiol, ethane-1,1-dithiol, and cyclohexane-1,1-dithiol. Upon heating, gem-dithiols often release hydrogen sulfide, giving the transient thioketone or thial, which typically convert to oligomers.[1]
1,2-Dithiols
Compounds containing thiol groups on adjacent carbon centers are common. Ethane-1,2-dithiol reacts with aldehydes (−CH=O) and ketones (>C=O) to give 1,3-dithiolanes:
Some dithiols are used in
dimercaptosuccinic acid
.
Enedithiols
Enedithiols, with the exception of aromatic examples, are rare. The parent aromatic example is
benzenedithiol. The dithiol of 1,3-dithiole-2-thione-4,5-dithiolate
2- is also known.
1,3-Dithiols
methyne (=CH−) group is sufficiently acidic that it can be deprotonated and the resulting anion can be C-alkylated. The process is the foundation of the umpolung phenomenon.[3]
Like 1,2-ethanedithiol, propanedithiol forms complexes with metals, for example with triiron dodecacarbonyl:
A naturally occurring 1,3-dithiol is dihydrolipoic acid.
1,3-Dithiols oxidize to give 1,2-dithiolanes.
1,4-Dithiols
A common 1,4-dithiol is
disulfide bond
.
thiol-disulfide exchange
reactions.References
- .
- PMID 17408840.
- ISBN 9780471936237.