Studies on the Alkaloids of Menispermaceous Plants. C. On the Structure of Biscoclaurine Alkaloids. (2). Cleavage of <i>O</i>-Methylrepandine by Metallic Sodium in Liquid Ammonia

Abstract

M. Tomita and Fujita previously decomposed O-methyloxyacanthine (II) by means of metallic sodium in liquid ammonia, and obtained two kinds of bisected bases, one of the d-type (III) and the other l-type (IV), thus verifying that the configuration of the asymmetric center at the right-hand tetrahydroisoquinoline nucleus in the molecule of (II) underawent inversion from d-type to l-type by this reaction.Moreover, it had already been clarified by Bruchhausen that when oxyacanthine (I) was reacted with 0.5 molar equivalent of hydrochloric acid, the configurations of the two asymmetric centers in its molecule underwent inversion from (+, +) to (+, -), and repandine (V) of its diastereoisomer was formed. In the present series of experiments, the authors carried out the decomposition of O-methylrepandine (VI) by metallic sodium in liquid ammonia, and proved two kinds of d-type (VII) and d-type (IX) as the bisected bases. Thus, it has been revealed that the configuration of the asymmetric center at the right-hand tetrahydroisoquinoline nucleus in (VI) again underwent inversion from l-type to d-type by this reaction.