1966 年 86 巻 10 号 p. 984-988
As the starting material for the synthesis of cepharanthine, 1-(p-benzyloxybenzyl)-8-bromo-2-methyl-6, 7-methylenedioxy-1, 2, 3, 4-tetrahydroisoquinoline (X) was successfully prepared. The amide (VII) was submitted to the usual Bischler-Napieralski reaction to obtain the 3, 4-dihydroisoquinoline (VIII) which was derived to its methiodide (IX), and its reduction with sodium borohydride afforded X. It was found that X is also obtained when the hydrochloride of VIII was reduced with sodium borohydride and its product submitted to the Eschweiler-Clarke reaction with formaldehyde and sodium borohydride. At the same time, it was also found that when IX was left in the air, the methylene in the 1-benzyl group was oxidized. There may be two directions in the cyclization of the amide (VII) but there was ample evidence that the cyclization occurred in the position ortho to the bromine atom since debromination of X with lithium aluminium hydride gave a substance which was in complete agreement with 1-(p-benzyloxybenzyl)-6, 7-methylenedioxy-1, 2, 3, 4-tetrahydroisoquinoline synthesized by another route.