Schotten‐Baumann reaction of the amine (X) with 4‐benzyloxy‐3,4′‐oxydiphenylacetyl chloride (XI) gave two amides, (XIIa) and (XIIb), which were cyclized to give the corresponding 3,4‐dihydroisoquinolines, respectively. Methylation of the above 3,4‐dihydro‐isoquinolines, followed by hydrolysis, afforded the compounds having the same composition as berbamine (Ia) and oxyacanthine (Ib), whose structures are under examination.