Preparation of 7,8-dimethoxy-3,4-dihydroisoquinolines, facile route to 7-8-dioxygenated-3,4-dihydroisoquinolines

Article abstract of DOI:10.1002/jps.2600731137

Oxidation of 7,8-dimethoxy-1,2,3,4-tetrahydroisoquinoline with potassium permanganate in acetone afforded 7,8-dimethoxy-3,4-dihydroisoquinoline as the primary product. Hence, oxidation of the appropriate secondary nonphenolic 7,8-dioxygenated tetrahydroisoquinoline alkaloid is thus a facile method for the generation of the corresponding imine. The imine is not easily prepared via the usual synthetic route involving ring closure of β-phenethylamine derivatives.