Studies on the syntheses of heterocyclic compounds. Part CCLXXXI. Synthesis of homoprotoberberine-type compounds by phenolic cyclisation

Abstract

The phenolic cyclisation of 1,2,3,4-tetrahydro-1-(3-hydroxy-4-methoxyphenethyl)-6,7-dimethoxyisoquinoline (VI) gave the homoprotoberberine-type compound (VII), in which cyclisation had taken place at the ortho-position to the hydroxy-group. The suggested structure for the compound, (VII), was assigned from spectroscopic results; the synthesis of the compound supported the suggested structure. A Mannich reaction of (VI) however, afforded a normal reaction product, homoprotoberberine (XV).