抄録
Bischler-Napieralski cyclization of the phenethylamide (VII) having a benzyloxyl group in the 3-position of the benzene ring was found to take place in the position para and ortho to the benzyloxyl group, but both isoquinoline derivatives could not be separated in the stage of 3, 4-dihydroisoquinolines (VIIIa and VIIIb), its methiodides (IXa and IXb), and 1, 2, 3, 4-tetrahydroisoquinolines (Xa and Xb), even if various procedures as thin-layer chromatography were examined. Accordingly, after Xa and Xb had been hydrolysed, attempt to separate both compounds (I and XI) by thin-layer chromatography was successfully carried out. After all, so-called corpaverine (I), namely, 8-hydroxy-6, 7-dimethoxy-1, 2, 3, 4-tetrahydro-1-(4-methoxybenzyl)-2-methylisoquinoline, was obtained besides its isomer (XI) in a comparatively better yield than that of our previous method. Furthermore, selective methylation of XIII with diazomethane also gave both compounds (I and XI), which were characterized as perchlorate and oxalate, respectively.
