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Grapefruit mercaptan

Grapefruit mercaptan
IUPAC name (R)-2-(4-methylcyclohex-3-enyl)propane-2-thiol
Other names grapefruit mercaptan
α,α,4-trimethylcyclohex-3-ene-1-methane thiol
CAS number racemate: 71159-90-5
R isomer: 83150-78-1
Molecular formula C10H18S
Molar mass 170.31 g/mol
Density 1.03 g/cm3
Melting point

<25 °C

Boiling point

58 °C at .33 mmHg

Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Grapefruit mercaptan is the common name for a natural organic compound found in grapefruit. It is a monoterpenoid that contains a thiol (or mercaptan) functional group. Structurally a hydroxy group of terpineol is replaced by the thiol in grapefruit mercaptan, so it also called thioterpineol. Volatile thiols typically have very strong, often unpleasant odors which can be detected by humans in very low concentrations. Grapefruit mercaptan has a very potent, but not unpleasant, odor and it is the chemical constituent primarily responsible for the aroma of grapefruit.[1] This characteristic aroma is a property of only the R-stereoisomer.[2]

Pure grapefruit mercaptan, or citrus-derived oils rich in grapefruit mercaptan, are sometimes used in perfumery and the flavor industry to impart citrus aromas and flavors. However, both industries actively seek substitutes for grapefruit mercaptans for use as a grapefruit flavorant, since its decomposition products are often highly disagreeable to the human sense of smell.


  1. ^ Buettner A., Schieberle P. (1999). "Characterization of the Most Odor-Active Volatiles in Fresh, Hand-Squeezed Juice of Grapefruit (Citrus paradisi Macfayden)". J. Agric. Food Chem. 47 (12): 5189-5193. doi:10.1021/jf990071l.
  2. ^ Lehmann D., Dietrich A., Hener U., Mosandl A. (1994). "Stereoisomeric flavor compounds. LXX: 1-p-menthene-8-thiol: separation and sensory evaluation of the enantiomers by enantioselective gas chromatography-olfactometry". Phytochemical Analysis 6 (5): 255-257. doi:10.1002/pca.2800060506.

See also

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Grapefruit_mercaptan". A list of authors is available in Wikipedia.
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