Coffee furanone explained

Coffee furanone (2-methyltetrahydrofuran-3-one) is a pleasant smelling liquid furan derivative which is a volatile constituent of the aroma complex of roasted coffee.^[1] Coffee furanone is less odorous than furfuryl mercaptan, which with an odor threshold of 0.005 ppb was the first high impact aroma chemical, but has a very pleasant sweet caramel character, with some nuttiness.^[2]

Synthesis

Coffee furanone was synthesized in 1963 by Wynberg via acid-catalyzed ring closure of β-alkoxy diazoketones.^[3] Coffee furanone has also been prepared via the condensation of ethyl lactate and methyl acrylate in DMSO solution^[4] and (under phase transfer conditions) in ionic liquids.^[5] A related lactic acid synthesis was described as having the advantages of a simple process, high conversion rate, low pollution, and low cost.^[6] This compound has also been prepared in acceptable yield via oxidative hydroxylation of the 2-acetylbutyrolactone.^[7] Further approaches to the synthesis of coffee furanone involved the hydrolysis of the corresponding dithioketals^[8] and the oxidation of 2-methyltetrahydrofuran employing lithium hypochlorite in the presence of ruthenium catalysts.^[9]

Applications

The synthetic version of this natural flavorant and odorant is used in a variety of food and beverage applications, including coffee, nuts, cocoa, brandy, meat sauces and as a general food flavorant at a typical dosage (about 5-20 ppm), similar to the natural concentration (30 ppm) of coffee furanone in roasted coffee.^{[10] [11]}

Notes and References

1. M. A. Gianturco . Volatile constituents of coffee. III. Structures of two heterocyclic compounds and the synthesis of tetrahydrofuranones . Tetrahedron . 20 . 1763–1772. 1964 . Friedel . P. . Giammarino . A. S. . 7 . 10.1016/s0040-4020(01)99177-x.
2. Leo M. L. Nollet, Terri Boylston, "Handbook of meat, poultry and seafood quality" page 137-138 (2007)
3. H. Wynberg. Tetrahydrofuran-3-one, spirans, and dithienyls. Angewandte Chemie. 75 . 10. 453. 1963. 10.1002/ange.19630751014.
4. M. A. Gianturco . Volatile constituents of coffee. III. Structures of two heterocyclic compounds and the synthesis of tetrahydrofuranones . Tetrahedron . 20 . 1763–1772. 1964 . Friedel . P. . Giammarino . A. S. . 7 . 10.1016/s0040-4020(01)99177-x.
5. Xiaogeng Liu . Synthesis of 2-methyltetrafuran-3-one from ethyl lactate and methyl acrylate. . Shipin Kexue (Beijing, China) . 26 . 165–167. 2005 . Chen . Yousheng . 5.
6. Cunzhao Cheng "Synthesis method of natural flavoring 2-methyltetrahydrofuran-3-one", Zhuanli Shenging Gonkai Shuomingshu, CN Patent 2009:1544311 (2009)
7. Valentine Ragoussis . A short and efficient synthesis of 2-methyltetrahydrofuran-3-one . Synthetic Communications . 28 . 4273–4278 . 1998 . Lagouvardos . Dimitrios J. . Ragoussis . Nikitas . 22 . 10.1080/00397919809458708.
8. Bonkoch Tarnchompoo . A condensed synthesis of dihydro-3(2H)-furanone . Tetrahedron Letters . 25 . 5567–70 . 1984 . Thebtaranonth . Yodhathai . 48 . 10.1016/s0040-4039(01)81628-2.
9. Mario Bressan . Selective oxygenation of aliphatic ethers catalyzed by ruthenium(II) complexes . Inorganic Chemistry . 29 . 2976–2979 . 1990 . Morvillo . Antonino . Romanello . Giorgio . 16 . 10.1021/ic00341a024.
10. M. A. Gianturco . Volatile constituents of coffee. III. Structures of two heterocyclic compounds and the synthesis of tetrahydrofuranones . Tetrahedron . 20 . 1763–1772. 1964 . Friedel . P. . Giammarino . A. S. . 7 . 10.1016/s0040-4020(01)99177-x.
11. R. Silwar . Gas chromatographic-mass spectrometric study of roasted coffee aroma - quantitative determination of steam-volatile aroma constituents . Chemie, Mikrobiologie, Technologie der Lebensmittel . 10 . 176–187. 1987 . Kamperschroer . H. . Tressl . R. . 5-6.