A new alkaloid (C19H21NO3, mp 197-198°, [α]27D −254°) was isolated from Argemone munita Dur. & Hilg. subsp. rotundata (Rydb.) G. B. Owmb. and was shown to be 2,9-dimethoxy-3-hydroxypavinane (I) by total synthesis. The synthesis was accomplished by formation of the Reissert compound from 7-methoxyisoquinoline and 3-methoxy-4-benzyloxybenzyl chloride, conversion to the benzylisoquinoline, N-methylation, reduction to the 1,2-dihydroisoquinoline, and cyclization to I with HCOOH and H3PO4. If the latter three steps were carried out on l-(4-methoxybenzyl)-6,7-dimethoxyisoquinoline, the final product under the HCOOH and H3PO4 conditions was not a pavinane alkaloid, but instead the rearranged product 3-(4-methoxybenzyl)-6,7-dimethoxy-1,2,3,4-tetrahydro-N-methylisoquinoline.
ASJC Scopus subject areas
- Organic Chemistry