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Ethane-1,2-dithiol

Ethane-1,2-dithiol, also known as EDT,[1] is a colorless liquid with the formula C2H4(SH)2. 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.[2]

Applications

As a 1,2-dithiol, this compound is widely used in organic chemistry because it reacts with aldehydes and ketones to give 1,3-dithiolanes, which are useful intermediates.[3]

C2H4(SH)2 + RR'CO → C2H4S2CRR' + H2O
Protecting a carbonyl group by converting it to a 1,3-dithiolane, using ethane-1,2-dithiol
Protecting a carbonyl group by converting it to a 1,3-dithiolane, using ethane-1,2-dithiol

Other 1,2- and 1,3-dithiols undergo this reaction to give related 1,3-dithiolanes and 1,3-dithianes (six-membered rings). Diols such as ethylene glycol undergo analogous reactions to 1,3-dioxolanes and 1,3-dioxanes. 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 is commonly used as a scavenger in peptide cleavage synthesis.

See also

References

  1. ^ Choi, H.; Aldrich, J.v. (1993-07-01). "Comparison of methods for the Fmoc solid-phase synthesis and cleavage of a peptide containing both tryptophan and arginine". International Journal of Peptide and Protein Research. 42 (1): 58–63. doi:10.1111/j.1399-3011.1993.tb00350.x. ISSN 1399-3011. PMID 8103765.
  2. ^ Speziale, A. J. (1963). "Ethanedithiol". Organic Syntheses; Collected Volumes, vol. 4, p. 401.
  3. ^ R. E. Conrow "Ethanedithiol" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi:10.1002/047084289X