Aconitum-Alkaloide (第9報)

各地産のトリカブト植物塩基 その4

抄録

The alkaloidal components of the rhizome of aconites collected at Shimoburo and Sakuma in Kazamura Village, Shimokita Peninsula in northeastern Honshu (Aomori Prefecture), were isolated and purified. Until the specie names can be determined, the plants are designated as Specimen Ochiai No. 15 and No. 16.
Ochiai No. 15 yielded 0.33% of crude bases (against the fresh rhizome) from which Shimoburo-base I, Shimoburo-base II, isohypognavine, and a crystalline base, m.p. 264-266°, were isolated. This component also contained a large amount of amorphous base. Ochiai No. 16 yielded 1.3% of crude base (against the dried rhizome) from which Shimoburo-base I, Shimoburo-base II, crystalline base of m.p. 267-267.5°, and small amounts of crystalline bases of m.p. 170°, m.p. 290° (decomp.), and m.p. 302° (decomp.), were isolated. This plant failed to yield isohypognavine.
The tentatively named Shimoburo-base I comes as prisms melting at 198-202°, [α]_D²⁴: -141.2° (MeOH), and can easily be isolated as a sparingly soluble hydrochloride of m.p. 278-279° (decomp.). It also gives a hydrobromide of m.p. 275° (decomp.), picrate of m.p. 225-229° (decomp.), and methiodide of m.p. 258-260° (decomp.), and its analytical values correspond to the formula C₂₁H₂₉O₃N or C₂₂H₃₁O₃N, its nitrogen is tertiary, it possesses one N-CH₃ or N-C₂H₅, but does not have a methoxyl or ester group. It forms a semicarbazone of m.p. 245-246° (decomp.).
The tentatively named Shimoburo-base II comes as crystals of m.p. 208-213°, [α]₁₉^D: 25.52° (CHCl₃), and formes a perchlorate of m.p. 223-226° (decomp.). Its composition agrees with C₂₃H₃₅O₇N or C₂₄H₃₇O₇N, possessing three methoxyls and one N-CH₃ or N-C₂H₅. It is resistant to hydrolysis and the presence of a carbonyl can be assumed from its absorption maximum at 295mμ (logε=1.63).
The base named isohypognavine was isolated as a hydrochloride of m.p. 195-198° (decomp.), [α]_D²²: +91.07 (MeOH). The free base is hard to crystallize but comes as prisms of m.p. 90-92°, which changes to m.p. 135° on drying. It forms a hydrobromide of m.p. 235-236° (decomp.), and a methiodide of m.p. 253-256° (decomp.), and its analytical values correspond to the formula C₂₇H₃₁O₅N, possessing a benzoyl group, but not methoxyl or N-methyl group.
The crystals of m.p. 267-267.5° from Ochiai No. 16 and m.p. 264-266° from Ochiai No. 15 are the same substances, giving [α]_D^12.4: +104.4° (MeOH), gives a picrate of m.p. 282-284°, methiodide of m.p. 286-287° (efferv.), and a perchlorate of m.p 213-214°. Its analytical values correspond to C₂₀H₂₇O₂N, and its properties resemble those of kobusine but no confirmatory evidences have been obtained as yet.