Abstract
As a part of our studies on the reactions of 1-ethoxyisochroman (1) with nucleophilic reagents, the reaction of 1 with benzylamines was examined. Heating of 1 with benzylamine or its derivatives having an electron-releasing or-attracting group at the 4-position gave 1-benzylaminoisochroman (2) or the corresponding 1-(4-substituted benzylamino) isochromans (6 and 7). Pyrolysis of 2, 6, and 7 gave 4-benzylisoquinoline (3) and 4-(4-substituted benzyl)-isoquinolines (8 and 9), respectively. Compound 3 was also obtained by heating 2-(2-hydroxyethyl) benzaldehyde with benzylamine, or by heating 2-vinylbenzylidenebenzylamine (4), while the reaction of 1 with N-methylbenzylamine afforded 1-(N-methylbenzylamino) isochroman (5) and did not give the 4-benzylisoquinoline derivative at all. The reaction mechanism giving 4-benzylisoquinolines is proposed to be as shown in Chart 3.
