Application of Norphenylephrine Derivatives to the Isoquinoline Syntheses : Studies on the Syntheses of Heterocyclic Compounds. CCCLII

A synthesis of 2-amino-(3-hydroxyphenyl) ethanol (I) was investigated as follow. Hydrolysis of 3-acetoxy-ω-(N, N-dibenzylamino) acetophenone (XVI), which was obtained from 3-acetoxy-ω-bromoacetophenone and dibenzylamine, gave the corresponding 3-hydroxy-derivative, whose catalytic hydrogenolysis with Pd-C afforded the above compound (I) as shown in Chart 1. Phenolic cyclization of I and 1-(3-hydroxyphenyl)-2-methylaminoethanol (II) was studied. Cyclization of I with cyclic ketones afforded three kinds of 1, 2, 3, 4-tetrahydro-1, 1-spiroheterocycloisoquinolines. Cyclization of amine (II) with carbonyl compounds was also carried out successfully to give five kinds of the corresponding 1, 2, 3, 4-tetrahydroisoquinolines. Furthermore, it was found that the cyclization occurred at the para position to phenolic hydroxy group.