Synthesen in der Isochinolinreihe Synthesen von 7‐Hydroxy ‐6‐methoxy‐2‐methyl‐ 1‐(4‐hydroxy‐3, 5‐dimethoxy‐phenäthyl)‐1, 2, 3, 4‐tetrahydro‐isochinolin, einem wichtigen Zwischenprodukt zur Synthese von Homoapomorphin‐Alkaloiden

Polymethoxylated 1‐phenethyl‐3, 4‐dihydro‐ and ‐1, 2, 3, 4‐tetrahydro‐isoquinolines were selectively demethylated by varying the mineral acid treatment. Under these conditions, the 6‐methoxyl was the most stable, while the 4′‐methoxyl was the most labile. Based on this study and by employing an unprotected phenolic intermediate in the Bischler‐Napieralski cyclization, an efficient, simple and technically feasible synthesis of the diphenol 1 , an important intermediate in the synthesis of homoapomorphine alkaloids, was achieved.