A pentacyclic aromatic alkaloid, kuanoniamine A (5) was synthesized from 6-methoxybenzothiazole-4,7-dione (7) and 2-aminoacetophenone (8). Similarly, 11-hydroxyascididemin (4) was prepared from 6-bromo-4-chloro-5,8-dimethoxyquinoline (12). The structure of neocalliactine acetate, a derivative of calliactine, was determined at 19 by total synthesis from 6-methoxy-5,8-quinolinedione (23) and 2-amino-5-methoxyacetophenone (24).
Efficient and Convenient Pyridine Ring-E Formation of the Cytotoxic Marine Alkaloid Ascididemin and Related Analogues.
作者:Brent S. Lindsay、A. Norrie Pearce、Brent R. Copp
DOI:10.1080/00397919708004128
日期:1997.8
Conversion of tetracyclic quinone 1 to the cytotoxic pentacyclic alkaloid ascididemin (2) in 80% yield is achieved by reaction with paraformaldehyde and ammonium chloride in refluxing acetic acid. High yielding annelations are also observed for the related analogues N-8 deaza ascididemin (3) and kuanoniamine A (4).