Stereochemistry and biosynthesis of 8-0-4′ neolignans in Eucommia ulmoides:: diastereoselective formation of guaiacylglycerol-8-0-4′-(sinapyl alcohol) ether
Stereochemistry and biosynthesis of 8-0-4′ neolignans in Eucommia ulmoides:: diastereoselective formation of guaiacylglycerol-8-0-4′-(sinapyl alcohol) ether
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DOI：
10.1007/s10086-004-0660-0
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发表时间：
2005-01-01
影响因子：
2.9
通讯作者：
Suzuki, T
中科院分区：
文献类型：
--
作者：
Lourith, N;Katayama, T;Suzuki, T
研究了杜仲中愈创木脂素-8-O-4 '-芥子醇醚（GGSE）的立体化学和生物合成。合成了4个8-O-4'-新木脂素GGSE、8-O-4'-松柏醇甘油醚（SGCE）、愈创木基甘油醚（GGCE）和8-O-4 '-芥子醇甘油醚（SGSE）。通过丙酮化合物衍生物（合成中间体）分离其邻位和苏型非对映异构体，并通过核磁共振（NMR）光谱进行鉴定。所有的赤型丙酮化合物的C-7-H共振的耦合常数（约9 Hz）均大于苏型丙酮化合物的耦合常数（1.5- 2 Hz）。在4个8-O-4'新木脂素中，苏式异构体的C-7-H偶合常数不小于反式异构体的C-7-H偶合常数。通过将C-13-NMR数据与合成赤型-GGSE和苏型-GGSE以及上述其他8-O-4'新木脂素进行比较，先前从该植物中分离的GGSE被鉴定为赤型异构体。将[8-C-14]松柏醇和[8-C-14]芥子醇的混合物施用于E. Ulmoides进行的，并发现C-14掺入到α-[C-14] GGSE中高于苏-[C-14]GGSE中。建议通过松柏醇和芥子醇的交叉偶联发生非对映选择性形成赤型-GGSE。
Stereochemistry and biosynthesis of guaiacylglycerol-8-O-4'-(sinapyl alcohol) ether (GGSE), an 8-O-4' neolignan, which consists of coniferyl and sinapyl alcohol moieties, in Eucommia ulmoides were investigated. Four 8-O-4' neolignans, GGSE, syringylglycerol-8-O-4'-(coniferyl alcohol) ether (SGCE), guaiacylglycerol -8-O-4'-(coniferyl alcohol) ether (GGCE), and syringylglycerol-8-O-4'-(sinapyl alcohol) ether (SGSE), were synthesized. Their erythro and threo diastereomers were separated through acetonide derivatives, intermediates of the synthesis, and identified by means of nuclear magnetic resonance (NMR) spectroscopy. All of the erythro-acetonide derivatives have larger coupling constants (ca 9 Hz) for the C-7-H resonances than those of the threo ones (1.5-2Hz). In the case of the four 8-O-4' neolignans, the C-7-H coupling constants of the threo-isomers are not smaller than those of the erythro ones. GGSE isolated previously from this plant was identified as the erythro isomer by comparison of the C-13-NMR data with synthetic erythro-GGSE and threo-GGSE and the other 8-O-4' neolignans mentioned as above. Administration of a mixture of [8-C-14] coniferyl alcohol and [8-C-14]sinapyl alcohol to excised shoots of E. ulmoides was carried out and the incorporation of C-14 into erythro[C-14]GGSE was found to be higher than that in threo-[C-14]GGSE. The occurrence of diastereoselective formation of erythro-GGSE by cross coupling of coniferyl and sinapyl alcohols is suggested.