Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München, Maximus-von-Imhof-Forum 2, D-85354 Freising, Weihenstephan, Germany.
Lehrstuhl für Biochemie, Technische Universität München, Lichtenbergstraße 4, D-85747 Garching, Germany.
J Agric Food Chem. 2020 Mar 4;68(9):2738-2746. doi: 10.1021/acs.jafc.0c00221. Epub 2020 Feb 18.
A homologous series (C6-C10) of 2-mercapto-4-alkanols was obtained by the addition of thioacetic acid to the respective alkenones and subsequent reduction with LiAlH. Gas chromatographic separation of the stereoisomers was achieved using chiral stationary phases. Their absolute configurations were assigned by the correlation of H NMR data and enzyme-catalyzed kinetic resolutions. Odor thresholds and odor qualities were determined by capillary gas chromatography/olfactometry. Compared to the odor qualities reported for the isomeric 4-mercapto-2-alkanols, the homologous series of 2-mercapto-4-alkanols lacked fruity, tropical notes. There was no consistent correlation between the configurations and the odor qualities. However, the observed odor thresholds indicated the importance of the configuration of the asymmetric center bearing the hydroxyl group and the alkyl substituent. The length of this alkyl chain is a main driver for the odor properties, ranging from pungent, vegetable to earthy, mushroom notes.
通过向相应的烯酮中添加硫代乙酸，然后用 LiAlH 还原，得到了 2-巯基-4-链烷醇的同系物（C6-C10）。使用手性固定相实现了立体异构体的气相色谱分离。通过与酶促动力学拆分相关联的 H NMR 数据，确定了它们的绝对构型。通过毛细管气相色谱/嗅闻法测定了气味阈值和气味品质。与报道的异构 4-巯基-2-链烷醇的气味品质相比，同系物 2-巯基-4-链烷醇缺乏果香、热带气味。构型和气味品质之间没有一致的相关性。然而，观察到的气味阈值表明，带有羟基和烷基取代基的不对称中心的构型非常重要。这个烷基链的长度是气味特性的主要驱动因素，范围从刺激性、蔬菜到泥土、蘑菇气味。
