Enantioselective Analysis of Secondary Alcohols and Their Esters in Purple and Yellow Passion Fruits
作者:Hedwig Strohalm、Márta Dregus、Astrid Wahl、Karl-Heinz Engel
DOI:10.1021/jf072464n
日期:2007.12.1
The enantiomeric compositions of the acetates, butanoates, hexanoates, and octanoates of the secondary alcohols 2-pentanol, 2-heptanol, and 2-nonanol were determined in yellow (Passiflora edulis f. flavicarpa) and purple (Passiflora edulis Sims) passion fruits. The compounds were isolated by means of simultaneous distillation-extraction. Enantiodifferentiation was performed via multidimensional gas chromatography using heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin as chiral stationary phase. The series of homologous 2-alkyl esters, which are typical constituents of purple passion fruits, were shown to be present as nearly optically pure (R)-enantiomers. The proportions of the (S)-enantiomers varied in different batches and were dependent on the alcohol moieties of the esters. For minor amounts of esters detected in yellow fruits, the (R)-enantiomers were also dominating. However, the enantiomeric excesses were significantly lower than in the purple variety. Enantioselective analysis of the free alcohols revealed that 2-heptanol exhibited opposite configurations in purple and yellow passion fruits. A similar phenomenon was observed for 2-pentanol, which was present in the yellow fruits as a nearly racemic mixture. Data determined in extracts obtained by other techniques (liquid-liquid extraction, vacuum headspace technique) showed that the isolation procedure had no significant impact on the enantiomeric ratios.
Schlenk,W., Justus Liebigs Annalen der Chemie, 1973, p. 1179 - 1194
作者:Schlenk,W.
DOI:——
日期:——
Preparation of Passion Fruit-Typical 2-Alkyl Ester Enantiomers via Lipase-Catalyzed Kinetic Resolution
作者:Hedwig Strohalm、Susanne Dold、Kathrin Pendzialek、Monika Weiher、Karl-Heinz Engel
DOI:10.1021/jf100432s
日期:2010.5.26
fruit-typical 2-alkyl esters by capillary gas chromatography using heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-β-cyclodextrin as chiral stationary phase. An efficient method was developed to prepare the ester enantiomers via lipase-catalyzed esterifications: optically pure (R)-2-alkyl esters (ee > 99.9%) were obtained by esterification of the racemic alcohols with enantioselective Candida antarctica
研究了通过脂肪酶催化动力学拆分制备仲醇2-戊醇,2-庚醇和2-壬醇的酯对映体(乙酸,丁酸酯,己酸酯和辛酸酯)。通过庚烷(2,3-di- O -methyl-6)的毛细管气相色谱法,对这些百香果类典型的2-烷基酯的同源系列进行了追踪,考察了市售酶制剂催化的酯化和水解反应的转化率和立体化学过程。- ø -叔丁基二)-β环糊精作为手性固定相。开发了一种通过脂肪酶催化的酯化反应制备酯对映体的有效方法:光学纯(R通过用对映选择性南极假丝酵母脂肪酶B(固定化)作为催化剂将外消旋醇酯化,可得到)-2-烷基酯(ee> 99.9%)。随后使用来自假丝酵母的脂肪酶将未反应的醇酯化,得到光学富集的(S)-酯(ee> 81.4%)。通过使用硅胶和氧化铝(碱性)的混合物的液体固体色谱法分离产物,得到高化学纯度和产率(> 40mol%)。