1957 Volume 77 Issue 10 Pages 1079-1082
Cleavage reaction of O-ethylberbamunine (III) with metallic sodium in liquid ammonia was found to form quantitatively l-N-methyl-O, O-diethylcoclaurine (IV) and d-1-(4-hydroxybenzyl)-2-methyl-6-methoxy-7-ethoxyl-1, 2, 3, 4-tetrahydroisoquinoline (V). This has confirmed the positions of three phenolic hydroxyls in the berbamunine molecule.
On the other hand, the phenolic base (VII), obtained from berbamine (VI) as an intermediate decomposition product in the first-step cleavage reaction with sodiumliquid ammonia, was methylated with diazomethane and the infrared absorption spectrum of the O-methyl ether (VIII) thereby obtained was compared with that of O-metllylberbamunine. As a result, the two substances were found to be entirely identical.
From the foregoing experimental results, it was proved that berbamunine would be represented by the structural formula (II) and that the configuration of the two asymmetric centers in its molecule would be (-, +).
