The alkaloid constituents of Euchresta japonica and the stereochemical assignment of two isomeric sophoridine N-oxides.
作者:SHIGERU OHMIYA、HIROTAKA OTOMASU、JOJU HAGINIWA、ISAMU MURAKOSHI
DOI:10.1248/cpb.28.546
日期:——
Nine known lupin alkaloids, (+)-matrine, (+)-matrine N-oxide, (+)-sophoranol, (+)-sophoranol N-oxide, (-)-sophoridine (1), (-)-cytisine, (-)-N-methylcytisine, (-)-N-formylcytisine, (-)-baptifoline, and (-)-sophoridine N-oxide (2a), were isolated from the aerial parts of Euchresta japonica BENTH., in addition to two alkaloids, (+)-5, 17-dehydromatrine N-oxide and (-)-12-cytisineacetic acid, reported previously. 2a was one of the two diastereoisomeric sophoridine N-oxides with different configurations of N-oxide nitrogen. Seasonal variations of the alkaloid contents in the aerial and ground parts of E. japonica were also examined. The N-oxidation of sophoridine with m-chloroperbenzoic acid gave two N-oxides in a ratio of ca. 1 : 5. The minor N-oxide was identical with 2a. The major N-oxide (2b) was characterized as the other diastereomer of sophoridine N-oxide by MS spectroscopy and deoxygenation to sophoridine. The stereochemical assignments of the two isomers were carried out by analysis of their 1H- and 13C-NMR spectra.
九种已知的羽扇豆生物碱,(+)-matrine、(+)-matrine N-氧化物、(+)-sophoranol、(+)-sophoranol N-氧化物、(-)-sophoridine (1)、(-)-cytisine、(-)-N-methylcytisine、(-)-N-formylcytisine, (-)-baptifoline, and (-)-sophoridine N-oxide (2a), were isolated from the aerial parts of Euchresta japonica BENTH.,此外,还分离出了两种生物碱,(+)-5, 17-dehydromatrine N-氧化物和(-)-12-cytisineacetic acid。2a 是两种非对映异构的槐定碱 N-氧化物之一,其 N-氧化氮的构型各不相同。此外,还研究了粳稻气生和土生部分生物碱含量的季节性变化。槐定碱与间氯过苯甲酸的 N-氧化反应产生了两种 N-氧化物,比例约为 1:5。次要的 N-氧化物与 2a 相同。主要的 N-氧化物(2b)通过质谱和脱氧生成槐定碱,被表征为槐定碱 N-氧化物的另一种非对映异构体。通过分析这两种异构体的 1H 和 13C-NMR 光谱,对它们进行了立体化学分配。