Bis(methylthio)methane

Description

2,4-Dithiapentane, aka bis(methylthio)methane, is the simplest alkyl dithioether. Horst B?hme and Robert Marx at the University of Berlin reported its synthesis in 1941. A quarter century later, A. Fiecchi and colleagues at the University of Milan and San Giorgio Essences (Turin, both in Italy) isolated it from white truffles (Tuber magnatum) and demonstrated that it is the odor principle of the highly valued fungus.
The odor of 2,4-dithiapentane in white truffles is mild; but in pure form it smells strongly like freshly prepared mustard. It would be nice to think that commercial products such as truffle oil, butter, and puree contain the natural substance; but most such products contain synthetic 2,4-dithiapentane.
That’s OK so long as these foodstuffs are labeled correctly. Counterfeit white-truffle products have been around for several years, but fakes would be more easily detected if there were a rapid analytical method for doing so.
Up stepped Luigi Mondello and collaborators at several Italian universities and private companies. They hypothesized that the 12C/13C isotope ratio would be different in natural and synthetic 2,4-dithiapentane because the compound would have dissimilar origins (fungus environment versus petroleum-based feedstock).
Sure enough, a gas chromatography–mass spectrometry technique showed that the natural thioether is richer in 13C? than the manufactured kind. The authors verified their findings by examining the isotope ratios of 2,4-dithiapentane extracted from a wide variety of truffle-flavored foods.

Chemical properties

CLEAR COLOURLESS TO PALE YELLOW LIQUID

Chemical properties

bis-(Methylthio)methane has a mustard-like odor.

Occurrence

Reported found in Camembert and Gruyere cheeses, milk, fish oil, cooked and canned beef, shitake mushroom, truffle, prawn and lobster.

The Uses of Bis(methylthio)methane

Bis(methylthio)methane is used in method for reducing odor in room in remodeling work by removing causative substances.

Definition

ChEBI: Bis(methylthio)methane is a dithioacetal.

General Description

The liquid structure of bis(methylthio)methane at room temperature was studied by the bonding and non-bonding interatomic potential functions (FMP-RMC) simulation.

Flammability and Explosibility

Not classified

Purification Methods

Work in an efficient fume cupboard as the substance may contain traces (or more) of methylmercaptan which has a very bad odour. Dissolve the mercaptal in Et2O, shake it with aqueous alkalis then dry it over anhydrous K2CO3, filter and distil it over K2CO3 under a stream of N2. If the odour is very strong, then allow all gas efluents to bubble through 5% aqueous NaOH solution which is then treated with dilute KMnO4 in order to oxidise MeSH to odourless products. UV: max 238 nm (log 2.73) [Fehnel & Carmack J Am Chem Soc 71 90 1949, Fehér & Vogelbruch Chem Ber 91 996 1958, B.hme & Marz Chem Ber 74 1672 1941]. Oxidation with aqueous KMnO4 yields bis-(methylsulfonyl)methane which has m 142-143o [Fiecchi et al. Tetrahedron Lett 1681 1967]. [Beilstein 1 IV 3088.]