Methoxydepsidan合成の試み (第1報)

2,3-Dimethoxydiphenyl Ether-2´-carboxylic Acid及び2-Amino-3-methoxydiphenyl Ether-2´-carboxylic Acidの合成

抄録

As a preliminary to the synthesis of methoxydepsidan (VI), a fundamental structure of insularine (I), the alkaloid of Cyclea insularis (Makino) Diels, several of its intermediates were prepared. 2, 3-Dimethoxydiphenyl ether-2′-carboxylic acid (IX) was prepared through the route shown in Fig. 1 but the yield from its Ullmann condensation was extremely poor. Methyl 2-amino-3-methoxydiphenyl ether-2′-carboxylate (XIV) was prepared by the route shown in Fig. 2 and attempt was made to decompose its diazonium salt to change the amino group with a hydroxyl but the objective substance was not obtained, and a substance in which the amino group had liberated, i.e. 3-methoxydiphenyl ether-2′-carboxylic acid (XV), a substance assumed to have undergone diphenyl condensation, i.e. 1-methoxydibenzofuran-6-carboxylic acid (XVI), and one other crystalline substance were obtained instead.