50 サンショウ属植物成分の研究 : Benzo〔c〕phenanthridine型アルカロイドの化学とIwamideの構造

概要

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Decarine (6), a monophenolic benzo[c]phenanthridine alkaloid, and iwamide (11), a modified amide from benzo[c]phenanthridine alkaloid, were isolated from the bark of Xanthoxylum arnottianum Maxim. In order to establish the location of the methoxy group of decarine (6), we measured the sift of the NMR spectra of several oxybenzo[c]phenanthridine alkaloids having an N-Et group instead of an N-CH_3 group by addition of shift reagent and observed a large shift of the signal due to a methoxy group to lower field in the case of chelerythrine series but due to an N-substituent in the case of nitidine series. The fact that the signal due to a methoxy group fairly shifted to lower field in the NMR spectra of N-methyl and N-ethyldecarine derivatives indicates that the methoxy group of decarine (6) situates at C_7 position of benzo[c]phenanthridine nucleus. On the other hand, we chemically converted decarine (6) into iwamide (11) via Baeyer-Villiger like oxidation of an immonium group which was developed in the case of structual establishments of arnottianamide (7) and isoarnottianamide (8).
天然有機化合物討論会の論文
1976-09-20