Isopropyl methoxypyrazine

Isopropyl methoxypyrazine (IPMP) is a methoxypyrazine, a class of chemical compounds that produce odors. The odor is rather undesirable and is produced by the Asian lady beetle or by the actinomycete Streptomyces sp.[2] It can be detected by human taste at concentrations of as low as 2 nanograms per litre.[3]

Isopropyl methoxy pyrazine
Chemical structure of isopropyl methoxypyrazine
Names
Preferred IUPAC name
2-Methoxy-3-(propan-2-yl)pyrazine
Other names
2-Isopropyl-3-methoxypyrazine
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.042.946
UNII
  • InChI=1S/C8H12N2O/c1-6(2)7-8(11-3)10-5-4-9-7/h4-6H,1-3H3 ☒N
    Key: NTOPKICPEQUPPH-UHFFFAOYSA-N ☒N
  • InChI=1/C8H12N2O/c1-6(2)7-8(11-3)10-5-4-9-7/h4-6H,1-3H3
    Key: NTOPKICPEQUPPH-UHFFFAOYAE
  • CC(C)C1=NC=CN=C1OC
Properties
C8H12N2O
Molar mass 152.19 g/mol
Hazards
GHS labelling:[1]
GHS07: Exclamation mark
Warning
H315, H319, H335
P302+P352, P305+P351+P338
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Presence in wine grapes

The odor of IPMP tends to be undesirable in the case of certain wines.[4]

Cabernet Sauvignon has high levels of methoxypyrazines.[5][6] Two methoxypyrazine compounds, 3-isobutyl-2-methoxypyrazine (IBMP) and 3-isopropyl-2-methoxypyrazine, are considered to be important determinants of green flavours in Sauvignon blanc wines.[7]

Presence in coffee

IPMP is also an important flavour compound in coffee and is responsible for causing an off-taste called "potato taste" in East African coffee.[8] The insects Antestiopsis are also implicated in causing the taste.[9]

See also

References
  1. GHS: sigma-aldrich 243132
  2. Three highly odorous metabolites from an actinomycete: 2-Isopropyl-3-methoxy-pyrazine, methylisoborneol, and geosmin. Nancy N. Gerber, Journal of Chemical Ecology, Volume 3, Number 4, pp. 475-482, doi:10.1007/BF00988190
  3. Cristina Sala; Olga Busto; Josep Guasch; Fernando Zamora. Factors affecting the presence of 3-alkyl-2- methoxypyrazines in grapes and wines. A review (PDF) (Report). Retrieved 2012-04-01.
  4. Trace flavour components of grapes
  5. winepros.com.au Oxford Companion to Wine methoxypyrazines Archived 2012-02-29 at the Wayback Machine
  6. Oz Clarke Encyclopedia of Grapes pg 223 Harcourt Books 2001 ISBN 0-15-100714-4
  7. Marais, J., Hunter, J.J., & Haasbroek, P.D. (1999). Effect of microclimate, season and region on Sauvignon blanc grape composition and wine quality. South African Journal of Enology and Viticulture, 20, 19-30.
  8. Czerny, M.; Grosch, W. (2000). "Potent Odorants of Raw Arabica Coffee. Their Changes during Roasting". Journal of Agricultural and Food Chemistry. 48 (3): 868–872. doi:10.1021/jf990609n. PMID 10725165.
  9. B. Bouyjou; B. Decazy; G. Fourny. "L'élimination du " goût de pomme de terre " dans le café Arabica du Burundi" [Removing the "potato taste" from Burundian Arabica]. Plantations, Recherche, Développement (in French). 6 (2): 107–115.
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