2,4-Dithiapentane

2,4-Dithiapentane is an organosulfur compound, and is the simplest alkyl dithioether. It is a colorless liquid with a strong odor, reminiscent of freshly prepared mustard in the pure form.

2,4-Dithiapentane is the dimethyldithioacetal of formaldehyde. Its synthesis was first reported in 1941. It is industrially prepared by the acid-catalyzed condensation of methyl mercaptan, the main aromatic compound in both halitosis and foot odor and a secondary compound in flatulence, with formaldehyde.
 * 2 CH3SH +  H2C=O   →   CH3SCH2SCH3  +  H2O

2,4-Dithiapentane is found as an aromatic component in some truffle varieties. A synthetic version is used as the primary aromatic additive in commercial "truffle" products, such as truffle oil, truffle butter, truffle salt and truffle pastes, many of which contain no truffle content at all, and have elevated levels of 2,4-dithiapentane compared to levels in natural truffle products. It has also been found to occur naturally in rotting wood of some species in the genus Lecythis.