Grapefruit mercaptan

Grapefruit mercaptan
IUPAC name (R)-2-(4-methylcyclohex-3-enyl)propane-2-thiol
Other names grapefruit mercaptan 1-p-menthene-8-thiol α,α,4-trimethylcyclohex-3-ene-1-methane thiol thioterpineol
Identifiers
CAS number	71159-90-5 Y,  (racemate) 83150-78-1 (R enantiomer)
ChemSpider	21163535 N
Jmol-3D images	{{#if:SC(C)(C)[C@@H]1CCC(C)=CC1|Image 1
SMILES SC(C)(C)[C@@H]1CCC(C)=CC1
InChI InChI=1S/C10H18S/c1-8-4-6-9(7-5-8)10(2,3)11/h4,9,11H,5-7H2,1-3H3/t9-/m0/s1 N Key: ZQPCOAKGRYBBMR-VIFPVBQESA-N N InChI=1/C10H18S/c1-8-4-6-9(7-5-8)10(2,3)11/h4,9,11H,5-7H2,1-3H3/t9-/m0/s1 Key: ZQPCOAKGRYBBMR-VIFPVBQEBF
Properties
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
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Grapefruit mercaptan is the common name for a natural organic compound found in grapefruit. It is a monoterpenoid that contains a thiol (aka 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 that 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 enantiomer.^[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.

See also

• Nootkatone, another aroma compound in grapefruit
• Terpineol, where a hydroxyl is in place of the thiol

References

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. PMID 10606593. 
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.