Yamamoto M, Takeuchi Y, Ohmasa Y, Yamazawa H, Ando T
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
Biomed Chromatogr. 1999 Oct;13(6):410-7. doi: 10.1002/(SICI)1099-0801(199910)13:6<410::AID-BMC902>3.0.CO;2-4.
The resolution of insect pheromonal cis-monoepoxy racemates derived from (Z,Z)-6,9-dienes was examined employing chiral HPLC columns, and the results showed that a normal-phase column (Chiralpak AD) was suitable for both 6,7- and 9,10-epoxides with a C(17)-C(23) straight chain, as was a reversed-phase column (Chiralcel OJ-R) for the 6, 7-epoxides. To determine the absolute configuration of each separated enantiomer applying a modified Mosher's method, the epoxy ring was opened by methanolysis, and the (1)H-NMR data of (S)- and (R)-MTPA esters of the methoxyalcohols produced were analyzed. Further, the hydrogenated product of each enantiomer was chromatographed on the OJ-R column referring to the corresponding authentic chiral compounds with a saturated chain, which were prepared by a Sharpless epoxidation reaction. These analyses showed that the levorotatory 6,7- and 9,10-epoxides with shorter t(R)s possess 6S,7R and 9R,10S configuration, respectively, and the dextrorotatory enantiomers with longer t(R)s possess the opposite configuration. Utilizing this chiral HPLC, it was revealed that an abdominal tip extract of the fruit-piercing moth, Oraesia excavata Butler (Lepidoptera: Noctuidae), included (9S,10R)-(Z)-9, 10-epoxy-6-henicosene as a main sex pheromone component. The synthetic 9,10-epoxide with this configuration, which was separated from the racemate, exhibited stronger activity in electrophysiological and field tests against male moths than the enantiomer.
采用手性高效液相色谱柱研究了源自(Z,Z)-6,9-二烯的昆虫信息素顺式单环氧化外消旋体的拆分，结果表明，正相柱（Chiralpak AD）适用于具有C(17)-C(23)直链的6,7-和9,10-环氧化物，反相柱（Chiralcel OJ-R）适用于6,7-环氧化物。为了应用改进的莫舍尔方法确定各分离对映体的绝对构型，通过甲醇解打开环氧环，并分析所生成的甲氧基醇的(S)-和(R)-MTPA酯的(1)H-NMR数据。此外，参照通过夏普莱斯环氧化反应制备的具有饱和链的相应真实手性化合物，在OJ-R柱上对各对映体的氢化产物进行色谱分析。这些分析表明，保留时间较短的左旋6,7-和9,10-环氧化物分别具有6S,7R和9R,10S构型，而保留时间较长的右旋对映体具有相反的构型。利用这种手性高效液相色谱法发现，果蛀蛾Oraesia excavata Butler（鳞翅目：夜蛾科）腹部末端提取物中包含(9S,10R)-(Z)-9,10-环氧-6-二十一碳烯作为主要性信息素成分。从外消旋体中分离得到的具有这种构型的合成9,10-环氧化物在针对雄蛾的电生理和田间试验中表现出比其对映体更强的活性。
