1966 年 86 巻 10 号 p. 973-975
It had been observed earlier that conversion of the ethoxycarbonyl group into acetyl in ethyl 6, 7-dimethoxy-1-methyl-3, 4-dihydro- and -1.2, 3, 4-tetrahydroisoquinoline-3-carboxylate was accompanied by dehydrogenation to form 3-acetyl-6, 7-dimethoxy-1-methylisoquinoline. In the present series of work, condensation of ethyl 6, 7-dimethoxy-3, 4-dihydro-(III) and-1, 2, 3, 4-tetrahydroisoquinoline-1-carboxylate (VI) with ethyl acetate and ketonic decomposition of its product was found to be also accompanied by dehydrogenation, as in the foregoing reaction, forming 1-acetyl-6, 7-dimethoxyisoquinoline (V). In order to prove the structure of V, III was submitted to dehydrogenation reaction and the compound VIII obtained as its product was submitted to the same reaction as above. The product thereby obtained was found to be identical with V obtained as above.