Reactivity of isocoumarins. III. Reaction of 1-ethoxyisochroman with benzylamines.
作者:MASATOSHI YAMATO、TADATAKA ISHIKAWA、TOSHIO KOBAYASHI
DOI:10.1248/cpb.29.720
日期:——
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.
作为 1-乙氧基异色满(1)与亲核试剂反应研究的一部分,我们还研究了 1 与苄胺的反应。将 1 与苄胺或其在 4 位具有释放或吸引电子基团的衍生物加热,可得到 1-苄氨基异色满(2)或相应的 1-(4-取代苄氨基)异色满(6 和 7)。热解 2、6 和 7 分别得到 4-苄基异喹啉(3)和 4-(4-取代苄基)-异喹啉(8 和 9)。化合物 3 还可以通过加热 2-(2-羟乙基)苯甲醛与苄胺或加热 2-乙烯基亚苄基苄胺 (4) 而得到,而 1 与 N-甲基苄胺反应得到 1-(N-甲基苄基氨基)异色原 (5),根本没有得到 4-苄基异喹啉衍生物。产生 4-苄基异喹啉的反应机理如图 3 所示。