Stephania capitata

Recently Kondo, Tomita, and Uyeo (55) applied the technique of chromatographic adsorption on alumina to the separation of the alkaloids of Cissampelos insularis Makino and Stephania cepharantha. By this means they isolated, in addition to those known, a new, crystalline, ether-soluble alkaloid whose analysis agreed with that of a bisbenzylisoquinoline alkaloid. This same alkaloid was also found in Chondodendron tomentosum (104) and Stephania capitata Spreng (121). Through a comparison of its properties and that of its derivatives with samples of isochondodendrine dimethyl ether and derivatives provided by Faltis, the Japanese workers (55) established the structure of the new alkaloid as being fully methylated isochondodendrine (LXI). They suggested the names methylisochondodendrine or cycleanine. An attempt to synthesize this alkaloid was not successful (130). Hovrever, by means of sodium and liquid ammonia the compound has been bisected into only one phenolic base whose structure proved to be M-(4 -hydroxybenzyl)-6,7-dimethoxy-iV-methyl-l,2,3,4-tetrahydroisoquinoline (134). This showed that cycleanine (methylisochondodendrine) has the structure (LXI) with both the asymmetric centers levorotatory. 

There are but two alkaloids in this small group, ( t-)-epistephanine (40) from three species (capitata, hernandifolia, and japonica) and one variety of these species (Japonica var. australis) of Stephania (Menispermaceae), and oxoepistephanine (47a) from Stephania hernandifolia (Menispermaceae). The two compounds differ only in the presence of the carbonyl function at the a carbon in oxoepistephanine. These alkaloids appear lo be restricted in distribution to Stephania species. 

Phanostenine, C19H19O4N, was first described by Tomita (44) as obtained from Stephania sasakii Hayata m.p. 210°, [a] — 36.7° (chloroform). It was subsequently isolated from S. capitata (45) and shown to have the above formula. It has one methoxyl and one hydroxyl, and upon methyla-tion with diazomethane affords an alkaloid shown to be Z-dicentrine (m.p. 160-165°) because when admixed with d-dicentrine there was formed the known dZ-dicentrine (m.p. 176°). Phanostenine can therefore have only one of two possible structures, namely, XVI, with one of the two meth-oxyls replaced by hydroxyl. 

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