Condensation of 2H-benzo[g][1,2]oxasilocines with aromatic aldehydes in the presence of boron trifluoride affords mixtures of cis/trans 2-phenyl-3-vinylchromans with moderate yields. These can be transformed into homopterocarpans, a synthetic group of substances homologous to the natural isoflavonoid pterocarpans.

The 5-deoxyisoflavones, afrormosin and formononetin have been isolated from healthy leaves of Onobrychis viciifolia. In addition to these compounds, several other flavonoid (isoliquiritigenin; liquiritigenin; garbanzol) and isoflavonoid (medicarpin; vestitol) derivatives including the new isoflavanone, vestitone (7,2'-dihydroxy-4'-methoxyisoflavanone), are present in leaves inoculated with the ...

Simple 7,2',4'-oxygenated isoflavans accumulate in the fungus-inoculated tissues of many papilionate legumes where they appear to function as defensive compounds (phytoalexins) [1, 2], Vestitol (7,2'-dihydroxy-4'-methoxyisoflavan, 1) is the most common isoflavan phytoalexin [3] and occurs widely in the Papilionoideae subfamily of the Leguminosae; in contrast, the related compound, isovestitol (...

Leguminosae, Pachyrrhizus, Isoflavonoids, Pterocarpans, Phytoalexins The furanopterocarpan, neodunol, has been isolated as a major phytoalexin from the fungusinoculated stems o f Pachyrrhizus erosus. Neodunol is accompanied by small quantities o f demethylmedicarpin and a third compound provisionally identified as the prenylated pterocarpan, homoedudiol; traces o f a neodunol isomer were also i...

Several papers have appeared in the literature since 1992 which refer to a major "isoflavonoid" antioxidant in young green barley leaves (Hordeum vulgare) as 2''-O-glucosylisovitexin. In the present paper the original NMR data supporting this structural assignment are examined and found to have been misinterpreted. HPLC and NMR data are used to prove that the major flavonoid antioxidants in you...

Leguminosae. Papilionoideae. Nissolia, Isoflavonoids, (-t-)-Pterocarpans Three isoflavonoid phytoalexins produced by the fungus or C u S 0 4-treated leaflets o f Nissolia fruticosa have been identified as (+ )6 aS ; 1 la5 -3 .7-d ihydroxy-9-m ethoxypterocarpan (nissicarpin). (+ )6 aS ; 1 la S-7-hydroxy-3 ,9-dim ethoxypterocarpan (fru ticarp in) and (+ )6 a.S; 11 aS-3,7-dihydroxy-2,9-dim ethoxyp...

Earlier studies [1, 2] have demonstrated that a number of isoflavonoid (pterocarpan) phytoalexins [3] accumulate in excised, fungus-inoculated leaflets of species belonging to the genus Lathyrus (Leguminosae-Papilionoideae; tribe Vicieae). Apart from pisatin (3-methoxy-6a-hydroxy-8,9-methylenedioxypterocarpan, 1), the most commonly en­ countered Lathyrus phytoalexin, small quantities of three o...