1,2-Ethanedithiol

1,2-Ethanedithiol, 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.

1,2-Ethanedithiol
Names
Preferred IUPAC name
Ethane-1,2-dithiol
Other names
Dimercaptoethane
1,2-Ethanedithiol
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.007.958
EC Number
  • 208-752-3
RTECS number
  • KI3325000
UNII
Properties
C2H6S2
Molar mass 94.19 g·mol−1
Appearance Colorless liquid
Density 1.123 g/cm3
Melting point −41 °C (−42 °F; 232 K)
Boiling point 146 °C (295 °F; 419 K) 46 mmHg
Slightly sol
Solubility in other solvents Good solubility in
most organic solvents
Acidity (pKa) ≈11
1.5589 (D-line, 25 °C)
Hazards
GHS pictograms
GHS Signal word Danger
GHS hazard statements
 H226, H301, H302, H310, H312, H319, H330
P210, P233, P240, P241, P242, P243, P260, P262, P264, P270, P271, P280, P284, P301+310, P301+312, P302+350, P302+352, P303+361+353, P304+340, P305+351+338, P310, P312, P320, P321, P322
NFPA 704 (fire diamond)
Flammability code 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity (yellow): no hazard codeSpecial hazards (white): no code
2
2
Flash point 50 °C (122 °F; 323 K)
Related compounds
Related thiols
 1,1-Ethanedithiol; Ethanethiol; 1,3-Propanedithiol; 1,2-Benzenedithiol; Thiophenol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Preparation

1,2-Ethanedithiol is prepared 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 1,2-ethanedithiol

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.; Collective Volume, 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:10.1002/047084289
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