Ethane-1,1-dithiol is an organosulfur compound with formula CH₃CH(SH)₂. It is a colourless smelly liquid that is added to or found in some foods. The compound is an example of a geminal dithiol.

Use

Flavouring uses of ethane-1,1-dithiol may include drinks, oil, gravy, soup, meat, fruit, seasonings, and snacks. Maximum concentrations in use that are generally recognised as safe (GRAS) is five parts per million (ppm) but typical uses are around 0.2 ppm. It is supplied as a 1% solution in ethanol, due to its strong offensive smell. In the diluted form with 4% ethyl acetate and ethanol the CAS number is 69382-62-3. Toxicity may be due to metabolism products hydrogen sulfide and acetaldehyde, however as used it has a margin of safety of over 10,000,000. Other ways that it is modified in the body apart from hydrolysis is methylation to 1-methylsulfanyl-ethanethiol, oxidation of the sulfur to an ethyl sulfonate,

glucuronidation Glucuronidation is often involved in drug metabolism of substances such as drugs, pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids, fatty acid derivatives, retinoids, and bile acids. These linkages involve gl ...

of the sulfur, or combination with cysteine by way of a disulfide bridge.

Identifiers

Since it is used in the food industry there are codes issued by various authorities. It is identified as JECFA number 1660. The

Flavor and Extract Manufacturers Association The Flavor and Extract Manufacturers Association (FEMA) is a food industry trade group based in the United States. FEMA was founded in 1909 by several flavor firms in response to the passage of the Pure Food and Drug Act of 1906. Founding members ...

(FEMA) id is 4111. The European designation for the flavouring is Fl 12.293.

Natural occurrence

It can be produced during fermentation of grapes. It is used as a food flavouring. It is found naturally in the scent of durian.

Properties

The nuclear magnetic resonance spectrum shows three environments for protons, in the ratio of 3:2:1 corresponding to CH₃ SH and CH.

Reactions

Ethane-1,1-dithiol has several reactions known that are important in white wine flavours. In the presence of oxygen, ethane-1,1-dithiol is converted to ''cis''/''trans''-3,6-dimethyl-1,2,4,5-tetrathiane which has a rubbery aroma. This molecule has a ring with four sulfur atoms and two carbons, two ethane-1,1-dithiol molecules become linked at their sulfur atoms with the loss of hydrogen. This can further oxidise to ''cis''/''trans''-3,5-dimethyl-1,2,4-trithiolane which has a meat-like odour. Ethane-1,1-dithiol reacts with hydrogen sulfide to form ''cis''/''trans''-4,7-dimethyl-1,2,3,5,6-pentathiepane, a ring containing five sulfur atoms and two carbons. This has a meaty smell.

Formation

Ethane-1,1-dithiol can be formed in the reaction of acetaldehyde with hydrogen sulfide. 1-Hydroxyethanethiol is formed as an intermediary.

References

External links

* * * {{DEFAULTSORT:Ethanedithiol, 1,1- Thiols Flavors Foul-smelling chemicals

Use