アキカラマツ Thalictrum Thunbergii DC.のアルカロイド研究 (第13報)

ThalicberineおよびO-Methylthalicberineの構造 その5

抄録

The structure of thalicberine and O-methylthalicberine, the new tertiary bases of Thalictrum thunbergii DC. (Japanese name “Aki-karamatsu”), had been indicated as Ia and Ib but the type of its ether bonding constituting the diphenyl ether binding two isoquinoline rings was so exceptional that further examinations were made to prove this structure.
O-Methylthalicberine methylmethine (II) was oxidized with ozone to (A) and (B) fragments. (B) afforded 4-methoxy-3, 4′-dihydroxybenzaldehyde (III) and aldehydic acids (IVa) and (IVb) as crystals. (A) afforded a diamino-dialdehyde, which was obtained as its dimethiodide (VIII) of m. p. 235°(decomp.), C₂₇H₄₀O₆N₂I⋅H₂O. It was submitted to the second Hofmann degradation, followed by catalytic and Clemmensen reductions, and derived to X, whose infrared spectrum (in CS₂) agreed with that of synthesized 2-methoxy-4-methyl-5-ethylphenyl 2-methyl-3-ethyl-5, 6-dimethoxy-phenyl ether. The whole route of this synthesis is indicated in Chart 1.
Ozone oxidation of O-methyloxyacanthine methylmethine (XII) by the route shown in Chart 2 afforded, as the basic decomposition product, a diamino-dialdehyde as its dimethiodide (XIV) of m. p. 245°(decomp.), C₂₇H₄₀O₆N₂I₂⋅H₂O. The infrared spectrum (in Nujol) of this dimethiodide (XIV) was entirely different from that of VIII, derived from O-methythalicberine methylmethine (II).
The present series of experiments has proved unequivocally that thalicberine and O-methylthalicberine are represented as Ia and Ib, respectively.