抄録
Trimethoxyaporphines (I) with methoxyls each in 1- and 2-positions and another methoxyl in 8-, 10-, or 11-position have already been synthesized, but not the one with the third methoxyl in 9-position. In the present series of work, 1, 2, 9-trimethoxyaporphine (II) was synthesized by the route shown in Chart 1. During the course of this synthesis, Pschorr's phenanthrene cyclization of the amine (IX) was found to produce the cleaved fragments, 2-methyl-6, 7-dimethoxy-1, 2, 3, 4-tetrahydroisoquinoline (X) and 5-methoxyindiazole (XI), besides the objective aporphine-type base (II), as well as trace amounts of a few other substances. There is a report that a diazo compound (XVI) is formed by diazotization of aminopapaverine (XV). In the present work, this reaction was followed by the formation of an intermediate (XVII) was assumed as a result of side reaction but the compound was not actually isolated. However, this intermediate may be assumed to undergo cleavage reaction, producting the two decomposition products, (X) and (XI). Example of such reaction is not found in any of the past literature.
Further, one-dimensional paper chromatography of dl-1, 2, 9-trimethoxyaporphine (II) was carried out and two spots of approximately the same size and intensity were produced (Fig. 2). This is thought to be due to dissolution of racemate by paper chromatography, as has deen reported in the literature. 5-Methoxyindiazole (XI) obtained as a by-product in the present reaction is a new substance not yet reported in any literature and the compound was synthesized by the route shown in Chart 2.
