1966 Volume 86 Issue 5 Pages 423-426
Refluxing of 1-(p-methoxybenzyl)-6, 7, 8-trimethoxy-3, 4-dihydroisoquinoline (I) in 20% hydrochloric acid for 5 hours resulted in demethylation of the 7-position, with oxidation of the methylene in the benzyl group in 1-position, affording 1-(P-methoxybenzoyl)-6, 8-dimethoxy-7-hydroxy-3, 4-dihydroisoquinoline (II). Reduction of II gave III, whose methylation produced IV, confirming the structure of II. In order to prove demethylation of the 7-position in I, the amine (X) was prepared from methyl 3, 5-dimethoxy-4-benzyloxybenzoate (V) via VI, VII, VIII, and IX, Schotten-Baumann reaction of X gave the amide (XI), which was cyclized and debenzylated. The final product of this reaction was identified with II by mixed fusion.
