Studies on the Bischler-Napieralski Reaction with Unsaturated Lactams. Syntheses of 5, 6, 9, 10, 11, 12-Hexahydro-2, 3-dimethoxybenzo [4, 5-a]-benzo [f] quinolizinium and Dihydrosempervirine Salts

Abstract

The Bischler-Napieralski cyclizations of 2-(3, 4-dimethoxyphenethyl) hexahydro-Δ^{4, 5}-3 (2H)-isoquinolone (V) and a mixture of V and the Δ^{5, 10}-isomer, yielded 1, 2, 3, 4, 4a, 5, 7, 8-octahydro-benzo [g] 10, 11-dimethoxybenzo [4, 5-a] pyridocolinium chloride (VI) and the corresponding isomeric mixture (XI), respectively, both of which were dehydrogenated to yield the same product, 1, 2, 3, 4-tetrahydrobenzo [g] 10, 11-dimethoxybenzo [4, 5-a] pyridocolinium iodide (VII). Dihydrosempervirine (XVII) was easily synthesized in the similar manner.