アキカラマツThalictrum Thunbergii DC.のアルカロイド研究 (第14報)

ThalicberineおよびO-Methyl-thalicberineの構造 その6

抄録

In order to elucidate the structure of the substance III, derived from the basic decomposition product of ozone oxidation of O-methylthalicberine methylmethine (I), synthesis of 2-methoxy-4-methyl-5-ethylphenyl 2-methyl-3-ethyl-5, 6-dimethoxyphenyl ether (II) was carried out.
One of the starting materials, 3-bromo-4-methyl-5-ethyl-1, 2-dimethoxybenzene (VIII), was synthesized from isovanillin (III) by its Clemmensen reduction to IV, introduction of acetyl group by the Friedel-Crafts reaction, Clemmensen reduction of its products to VI, bromination to VII, and finally by O-methylation to VIII. The other substance XVI was synthesized from m-cresol (IX) by its acetylation to X, Fries rearrangement followed by Clemmensen reduction to XII, and O-methylation to 3-methyl-4-ethylanisole (XIII), which was reduced and hydroxyl group introduced through diazotization. The position of this hydroxyl group was confirmed through the negative Gibbs reaction and identity of the infrared spectrum (in CHCl₃) of the O-methyl ether (XVII) of this substance with that of O-methyl ether (XVII) of VI synthesized by a known method.
The Ullmann condensation of these 3-bromo-4-methyl-5-ethyl-1, 2-dimethoxybenzene (VIII) and 2-methoxy-4-methyl-5-ethylphenol (XVI) gave the desired substance (II).