Studies on the Syntheses of Heterocyclic Compounds. LII. The Eschweiler-Clarke and Pictet-Spengler Reactions with β-Methoxysafrylamine.

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The Eschweiler-Clarke and Pictet-Spengler reactions of β-methoxysafrylamine were examined. In the former reaction N, N-dimethyl-β-methoxysafrylamine was obtained in place of expected isoquinoline, but in the latter reaction four kinds of isoquinoline derivatives were formed according to reaction conditions of time and temperature. When heated for 30 minutes with formaldehyde solution, 3-methyl-1, 2-dihydro-(IV) and 3-methyl-4-methoxy-1, 2, 3, 4-tetrahydro-6, 7-methylenedioxyisoquinoline (III) were obtained, while 2, 3-dimethyl-1, 2-dihydro-(VII) and 2, 3-dimethyl-1, 2, 3, 4-tetrahydro-6, 7-methylene-dioxyisoquinoline (VI) were obtained when heated for 7 hours. Especially in the latter case, it is interesting that 4-methoxy derivative is obtained only by heating with formaldehyde solution although it could not be synthesized by the Bischler-Napieralski reaction and that, in addition, the substance (VII) was obtained very easily by way of (VI).