1963 年 83 巻 4 号 p. 356-360
As one of the series studies of the syntheses of water soluble papaverine analogs, amongst six derivatives possessing two hydroxyl groups in the phenyl ring at 1-position of isoquinoline ring, 2, 4-, 2, 5-, 3, 4- and 3, 5-dihydroxy compounds were already synthesized. In the present study 2, 3- and 2, 6-dihydro and 2-hydroxy-6-methoxy derivatives were synthesized. 2, 3-Dihydroxy derivative was synthesized from methyl 2, 3-dihydroxybenzoate via the dibenzyl ether carboxylic acid chloride. The latter was condensed with α-methyl-β-methoxy-3, 4-methylenedioxy-β-phenethylamine into the amide which was subjected to a ring closure reaction with phosphorus oxychloride to isoquinoline derivative and then debenzylated. 2-Hydroxy-6-methoxy derivative was obtained from 2′, 6′-dihydroxyacetophenone via 2-benzyloxy-6-methoxy compound, carboxylic acid chloride which was condensed with amine to acid amide and applied to ring closure reaction with phosphorus oxychloride and then debenzylated. 2, 6-Dihydroxy derivative was synthesized by demethylation of isoquinoline derivative obtained from 2, 6-dimethoxybenzoic acid. The amide which is an intermediate of 2, 6-dihydroxy derivative exists in two forms, m. p. 214-215° and m. p. 130.5-132.5°.