Synthesis and organoleptic properties of various 3‐methyl‐2‐oxopentanoates, 2‐hydroxy‐3‐methylpentanoates, and 2‐acyloxy‐3‐methylpentanoates
Synthesis and organoleptic properties of various 3‐methyl‐2‐oxopentanoates, 2‐hydroxy‐3‐methylpentanoates, and 2‐acyloxy‐3‐methylpentanoates
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DOI：
10.1002/ffj.1510
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发表时间：
2005-07
影响因子：
2.6
通讯作者：
R. Snowden;Raphaël Grenno;C. Vial
中科院分区：
文献类型：
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作者：
R. Snowden;Raphaël Grenno;C. Vial
作为涉及发现新香料成分的研究计划的一部分，制备了一系列外消旋3-甲基-2-氧代戊酸烷基酯2-8、2-羟基-3-甲基戊酸乙酯和甲酯（分别为13/14和15/16）以及2-酰氧基-3-甲基戊酸甲酯和乙酯17-32，并评价了它们的感官性能。3-甲基-2-氧代戊酸乙酯（3）具有浓郁的新鲜核桃果香，因此分别从（L）-（+）-异亮氨酸（（+）-9）和（L）-（+）-别异亮氨酸（（+）-10）选择性地合成了3-甲基-2-氧代戊酸乙酯（3）。虽然（+ + + +）-3和（− − −）-3具有相似的气味特征，但（+ + ++ +）-3比其对映体更强烈，刺激性更小。还发现中间体羟基酯（+）-13和（+）-14具有明显的胡桃特征，它们各自的对映体（-）-13和（-）-14也是如此。除了13/14（坚果、泥土、水果味）、15/16（核桃、可可、角豆）和25/26（水果味、甘菊、角豆）之外，发现其他化合物的感官特性不太令人感兴趣，表现出各种弱水果味、甘菊、豆和药用香调。版权所有© 2005年约翰威利父子有限公司。
As part of a research programme concerned with the discovery of new perfumery ingredients, a series of racemic alkyl 3-methyl-2-oxopentanoates 2-8, ethyl and methyl 2-hydroxy-3-methylpentanoates (13/14 and 15/16, respect- ively), together with methyl and ethyl 2-acyloxy-3-methylpentanoates, 17-32, have been prepared and their organoleptic properties evaluated. Ethyl-3-methyl-2-oxopentanoate (3), exhibiting a strong, fresh walnut, fruity odour, is of special interest, and its enantiomers were thus selectively synthesized from (L)-(+)-isoleucine ((+)-9) and (L)-(+)-allo-isoleucine ((+)- 10), respectively. Whilst (+ + + +)-3 and (− − − −)-3 have a similar odour profile, (+ + + + +)-3 is more powerful and less pungent than its antipode. The intermediate hydroxy esters (+ + + + +)-13 and (+)-14 were also found to have a distinct walnut character, as did their respective enantiomers, (−)-13 and (−)-14. Apart from 13/14 (camphoraceous, earthy, fruity), 15/16 (walnut, cacao, carob bean) and 25/26 (fruity, camomile, carob bean), the organoleptic properties of the other compounds were found to be less interesting, exhibiting a variety of weak fruity, camomile, bean and medicinal notes. Copyright © 2005 John Wiley & Sons, Ltd.