防已科植物アルカロイド研究 (第166報)

コウシウウヤクのアルカロイド (補遺 14) dl-N, 4´-Dimethylisococlaurineの合成

抄録

dl-N, 4′-Dimethylisococlaurine (VI) is the phenolic by-product obtained on cleavage of isotetrandrine (I) with metallic lithium in liquid ammonia, with dioxane as a solvent. The racemic compound of (VI) was synthesized by the route of (IX)→(X)→(XI)→(XII)→(VI), obtained as a free base of m.p. 45° and a picrate of m.p. 138°. Infrared absorption spectra of the two showed them to have identical structure and the structure of (VI) was thus synthetically confirmed. Attempted reduction of 3, 4-dihydroisoquinoline compound (X) to (XII) in one step with palladium-carbon catalyst afforded a benzoyl compound (XIII) as a by-product and its structure was identified.