2-Methoxy-3,5-dimethylpyrazine
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| IUPAC name
2-methoxy-3,5-dimethylpyrazine
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| Other names
3,5-dimethyl-2-methoxypyrazine
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| Properties | |
| C7H10N2O | |
| Molar mass | 138.170 g·mol−1 |
| Appearance | Colorless to pale yellow liquid |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
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2-Methoxy-3,5-dimethylpyrazine (sometimes abbreviated as MDMP) is a heterocyclic organic compound, part of methoxypyrazine class. It has a highly potent aroma with a strong musty, moldy, or earthy scent. It is best known as a source of cork taint in wine, secondary in importance to 2,4,6-trichloroanisole (TCA).[1]
Natural occurrence
2-Methoxy-3,5-dimethylpyrazine has been identified as a natural product and a volatile organic compound responsible for off-odors in various products. It is a significant contributor to the "fungal must" or "corky" taint in wine, which is distinct from the smell caused by TCA.[1] The compound is not only found in cork stoppers but can also be present in oak wood used for barrel making.[2] Its presence has also been detected in coffee.[3]
The bacterium Rhizobium excellensis, which is widespread in the soil, is capable of producing 2-methoxy-3,5-dimethylpyrazine from amino acid precursors such as L-leucine and L-alanine.[2] The compound has also been identified as the cause of musty odors in public water supplies.[4]
Aroma
The aroma of 2-methoxy-3,5-dimethylpyrazine is variously described as musty, moldy, earthy, "like a potato bin", or reminiscent of wet cork and fresh hazelnuts.[2][1] It is an extremely potent odorant with a very low odor detection threshold. In white wine, its threshold has been determined to be as low as 2.1 nanograms per liter.[1] This potency means that even trace amounts of the compound can have a significant negative impact on the sensory profile of a wine or other beverage.
Synthesis
The synthesis is described in detail by Simpson et al.[1][5]
References
- ^ a b c d e Simpson, Capone & Sefton 2004.
- ^ a b c Chatonnet et al. 2010.
- ^ Czerny & Grosch 2000, p. 868.
- ^ Ventura et al. 2009.
- ^ Chatonnet et al. 2010, p. 12482.
Sources
- Chatonnet, Pascal; Cunha, Jorge; Rosenthal, Didier; Pons, Monique (8 December 2010). "Origin and Incidence of 2-Methoxy-3,5-dimethylpyrazine, a Compound with a "Fungal" and "Corky" Aroma Found in Cork Stoppers and Oak Chips in Contact with Wines". Journal of Agricultural and Food Chemistry. 58 (23): 12481–12490. Bibcode:2010JAFC...5812481C. doi:10.1021/jf102874f. PMID 21058737.
- Czerny, Michael; Grosch, Werner (2000-03-01). "Potent Odorants of Raw Arabica Coffee. Their Changes during Roasting". Journal of Agricultural and Food Chemistry. 48 (3): 868–872. Bibcode:2000JAFC...48..868C. doi:10.1021/jf990609n. ISSN 0021-8561. PMID 10725165. Retrieved 2025-07-06.
- Simpson, Robert F.; Capone, Dimitra L.; Sefton, Mark A. (2004-08-01). "Isolation and Identification of 2-Methoxy-3,5-dimethylpyrazine, a Potent Musty Compound from Wine Corks". Journal of Agricultural and Food Chemistry. 52 (17): 5425–5430. Bibcode:2004JAFC...52.5425S. doi:10.1021/jf049484z. ISSN 0021-8561. PMID 15315380. Retrieved 2025-07-05.
- Ventura, Francesc; Quintana, Jordi; Gómez, Mariano; Velo-Cid, Mónica (2009). "Identification of 2-methoxy-3,5-dimethylpyrazine as the obnoxious compound at trace levels in water supplies". AWWA Water Quality Technology Conference. American Water Works Association.