Alkaloids of monimiaceous plants

Alkaloid-bearing plants of the Australian Monimiaceae have generally yielded alkaloids of the bisbenzylisoquinoline type. For this reason a brief outline of the chemistry of this class of compound will be presented; a more detailed account may be found in a complete and thorough review by Grundon 1. The bisbenzylisoquinoline molecule consists of two benzylisoquinoline moieties linked by one, two or three oxygen atoms; these ether bridges are believed to arise by intermolecular dehydrogenation of two molecules of 1-(4-hydroxybenzy1)-6,7-dehydroxy-1,2,3, 4-tetrahydroisoquinoline in which the new C-0 bond is formed by phenolic coupling at nuclear positions ortho to hydroxyl groups. The route which the dehydrogenation follows leads to the classification of bisbenzylisoquinoline alkaloids into several different classes.