メギ科植物アルカロイド研究 (第30報)
オオバメギBerberis Tschonoskiana REGELのアルカロイド その3 Obaberineの構造
1960 年 80 巻 10 号 p. 1425-1428
詳細
1960 年 80 巻 10 号 p. 1425-1428
A new base named obaberine was isolated as the tertiary, non-phenolic base from Berberis Tschonoskiana REGEL (Japanese name ‘Ohba-megi’) as needle crystals of m. p. 139-140°, and other crystalline new bases of m. p. 57-58° and m. p. 105-107° were also found to be present.
Obaberine is a non-phenolic base indicated by the molecular and empirical formulae of C38H42O6N2=C32O24(OCH3)4(-O-)2(NCH3)2. Various reactions of this base such as the Hofmann degradation of its methiodide, oxidation of its methine base with potassium permanganate, and cleavage reaction with sodium in liquid ammonia revealed that this base is an oxyacanthine type of biscoclaurine bases and its data were very similar to those of O-methyloxyacanthine (III) (cf. Table I). Whereas obaberine forms crystals melting at 139-140°, O-methyloxyacanthine is derived by methylation with diazomethane of oxyacanthine, which had been known for scores of years as an amorphous base. Attempted crystallization of O-methyl-oxyacanthine in the present series of experiments successfully afforded it as needle crystals of m. p. 139-140°. Obaberine and O-methyloxyacanthine (III) were proved to be the same substances by comparative identification through admixture and infrared absorption spectra (in Nujol) of the free bases as well as their picrates. Oxyacanthine (II) is known to be distributed widely in Berberis sp. plants and its methyl ether, obaberine (O-methyloxyacanthine) (III), has now been found for the first time in nature, in Berberis Tschonoskiana REGEL.
