Ethane-1,2-dithiol

Ethane-1,2-dithiol, also known as EDT, is a colorless liquid with the formula C H. It has a very characteristic odor which is compared by many people to rotten cabbage. It is a common building block in organic synthesis and an excellent ligand for metal ions.

Preparation

Ethane-1,2-dithiol is made commercially by the reaction of 1,2-dichloroethane with aqueous sodium bisulfide. In the laboratory, it can also be prepared by the action of 1,2-dibromoethane on thiourea followed by hydrolysis.

Reactions

1,2-Ethanedithiol is a weak acid, typical of alkyl thiols. In the presence of base and an alkylating agent, 1,2-ethanedithiol converts to thioethers:
Oxidation of 1,2-ethanedithiol gives a series of oligomers, including the cyclic bis.
As a 1,2-dithiol, this compound reacts with aldehydes and ketones to give 1,3-dithiolanes, which can be useful intermediates.
Other 1,2- and 1,3-dithiols give related 1,3-dithiolanes and 1,3-dithianes. Diols such as ethylene glycol undergo analogous reactions to give 1,3-dioxolanes. One distinguishing feature of the dithiolanes and dithianes derived from aldehydes is that the methyne group can be deprotonated and the resulting carbanion alkylated.
1,2-Ethanedithiol has been used as a scavenger in peptide cleavage synthesis.
Like 1,3-propanedithiol, 1,2-ethanedithiol readily forms metal thiolate complexes. Illustrative is the synthesis of the derivative diiron ethanedithiolate hexacarbonyl upon reaction with triiron dodecacarbonyl: