Abstract
A synthesis of 3-methyl-9, 10-methylenedioxy-1, 2, 3, 3a, 4, 5, 11b, 11c-octahydro-7H-pyrrolo [3, 2, 1-de] phenanthridine (XIV) having common hydropyrrolophenanthridine skeleton with several of the Amaryllidaceae alkaloid such as lycorine, pulviine, caranine etc., was described. 2-(3, 4-Methylenedioxyphenyl)-5-methylcyclohexanone (VI) prepared from safrole was used as the starting material. This synthesis had recourse to the fact that the starting ketone underwent the Mannich reaction with formaldehyde and dimethylamine at its 6-position and not at 2-position to give 2-3, 4-methylenedioxyphenyl-5-methyl-6-dimethylaminomethylcyclohexanone (VII). This fact was evidenced by the ultraviolet absorption date showing the presence of an ethylene bond conjugated to the aromatic ring in the unsaturated lactam (IX) prepared from (VI) via the 2-oxo-cyclohexaneacetonitrile (VIII) by Campbell cyclization. Catalytic hydrogenation followed by lithium aluminium hydride reduction converted (VIII) into octahydroindole derivative (XIII) through the saturated lactam (XII). The ultimate base (XIV) was readily obtained from (XIII) by the conventional Pictet-Spengler method.
