Studies on Tetrahydroisoquinolines. XXVI. : A Biomimetic Synthesis of 5-Oxygenated 1,2,3,4-Tetrahydroisoquinolines

Treatment with acetic anhydride-conc. sulufuric acid of o-quinol acetates (7, 11, 18, 19, 20, 28 and 34), which were derived from the corresponding 6-hydroxy-7-methoxytetrahydroisoquinolines (6, 12, 15, 16, 17, 27 and 31), gave the 5, 6-diacetates (8, 13, 21, 22, 23, 29 and 33, respectively). The diacetates were transformed into the corresponding 5, 6, 7-trimethoxytetrahydroisoquinolines (10, 14, 24, 25, 26, 30 and 32) by hydrolysis and subsequent methylation.