28 ウオトリマメ由来新規イソフラボノイド類の構造研究(ポスター発表の部)

概要

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In the course of our isoflavonoid research in Leguminosae, an unprecedented amino-substituted isoflavone was isolated from the root bark of Piscidia erythrina L. The root bark of P. erythrina collected in Mexico was extracted with methanol and the extracts were fractionated by Si gel column chromatography. A series of preparative TLC made it possible to isolate piscerythramine (1). The reaction of 1 with Ehrlich's reagent to yield a yellow pigment on Si gel thin layer plates suggested the presence of an amino group in the molecule. The FD-MS spectrum showed the molecular ion at m/z 451, and EI-HR-MS (M^+ 451.1997) revealed the molecular formula to be C_<26>H_<29>NO_6. ^1H-NMR, UV and EI-MS indicated 1 to be a 5,7-dihydroxylated isoflavone with two prenyl groups on the B-ring. The structure was established as 4'-amino-5,7,3'-trihydroxy-5'-methoxy-2',6'-bis(3,3-dimethylallyl)isoflavone from the results of the extensive NOE experiments and of methylation reaction. This is the first report on naturally occurring amino-flavonoids. In this connection, we revised the structure of a diprenyl isoflavone reported as 6'-prenylpiscerythrone (5,7,2',4'-tetra-hydroxy-5'-methoxy-3',6'-bis(3,3-dimethylallyl)isoflavone), which was one of the major isoflavone found in P. erythrina, to be 5,7,3',4'-tetrahydroxy-5'-methoxy-2',6'-bis(3,3-dimethylallyl)-isoflavone.
天然有機化合物討論会の論文
1990-09-25