A Simple Synthesis of Amphimedine

Abstract

The marine alkaloid amphimedine has been synthesized by a short sequence of reactions commencing from the known indenopyridinedione (2). Reaction with 4-pyridyllithium, followed by hydrazoic acid treatment, gave 5-(4-pyridyl)-3,6-phenanthrolin-4(3H)-one (12) which was converted into the chlorophenanthroline. The methyl-substituted fluorosulfonate salt of this compound was specifically oxidized by alkaline ferricyanide. Conversion of the pyridone into the nitrile gave the precursor which was cyclized to amphimedine by polyphosphoric acid.