Fujio Asai

Five complex flavonoids in the farinose exudate of Pityrogramma calomelanos

Abstract From the farinose exudate of Pityrogramma calomelanos, five new complex flavonoids named calomelanols F–J were isolated. Calomelanol F was characterized as a linear structure, and those of calomelanols G, H, I and J as angular structures from spectroscopic evidence.

Complex flavonoids in farinose exudate from Pityrogramma calomelanos

Abstract From the farinose exudate of Pityrogramma calomelanos, three new complex flavonoids named calomelanols A–C were isolated in addition to two known dihydrochalcones. The structures were characterized as 8-[3-(4-methoxyphenylpropionyl)]-5,7-dihydroxydihydroneoflavone for calomelanol A, 8-[3-(4-hydroxyphenylpropionyl)]-5,7-dihydroxydihydroneoflavone for calomelanol B, and 8-(3-phenylpropionyl)-5,7,4′-trihydroxydihydroneoflavone for calomelanol C, respectively, by spectroscopic evidence. The 13C NMR assignment and the mass spectral fragmentation of the complex flavonoids are also described.

Flavonoids in frond exudates of Pityrogramma tartarea

Abstract From the frond exudate of Pityrogramma tartarea, a new dihydrochalcone, 2′,6′-dihydroxy-3,4,4′-trimethoxydihydrochalcone, and five complex flavonoids (D-1, D-2/a, calomelanols D, F and H) were isolated in addition to three known chalcones, three dihydrochalcones and three flavanones. Naturally occurring compounds which are assumed to be transformed from secondary metabolites in vitro by physical factors as found in exudates of species, such as Pityrogramma, Pentagramma, Primula etc., are defined as ‘tertiary metabolites’.

Two xanthones from Root Bark of Garcinia subelliptica.

Abstract Two new prenylated xanthones (subelliptenones E and F) and a new simple oxygenated xanthone (subelliptenone G) were isolated from the root bark of Garcinia subelliptica in addition to a known xanthone (1,5-dihydroxy-3-methoxyxanthone). The structures were determined by means of spectroscopic analysis.

Two xanthones with a 1,1-dimethylallyl group in root bark of Garcinia subelliptica

Two new prenylated xanthones, subelliptenone H and I, were isolated from the root bark of Garcinia subelliptica. The structures were determined by NMR spectroscopy including 2D techniques and chemical transformation. They both had a 1,1-dimethylallyl group and an isoprenyl group cyclized with the O-function.

Spectral characters of a complex flavonoid isolated from the farinose exudate of Pityrogramma calomelanos

Abstract A complex flavonoid, previously referred to as ‘D-2/b’, was isolated from the farinose frond exudate of the fern Pityrogramma calomelanos in a pure state. Its earlier suggested structure, 8-(2-carboxyl-1-phenylethyl)-5,7-dihydroxyflavone δ-lactone, is confirmed by complete NMR analysis.

Revised structure of neoflavone in Coutarea hexandra

Abstract A new neoflavone isolated from Coutarea hexandra , thought to be 5,2′,5′-trihydroxy-7-methoxyneoflavone, is now shown to be 5,3′,4′-trihydro

Complex flavonoids from Pityrogramma frond exudates: synthesis of two flavones with C―C-linked dihydrocinnamoyl substituents

Abstract Complex flavonoids that are typical for the frond exudate in ferns of the genus Pityrogramma are surveyed to demonstrate their close structural relation. Two such compounds, isolated earlier from the exudate of Pityrogramma calomelanos var. aureoflava are prepared by an unambiguous synthesis. Direct comparisons of the synthetic products, namely P-(5,7.4′-trihydroxy-8-yl)-β- phenylpropionic acid and its methyl ester, show them to be identical with the natural products. The structures deduced previously for these compounds by spectroscopic methods are thus confirmed.