Isolation and Identification of Isoflavanone Phytoalexins from Leaflets of Diphysa robinioides

Leguminosae, Papilionoideae, Diphysa, Isoflavonoids, Isoflavanones A m ajor phytoalexin produced by the fungus-inoculated leaflets o f Diphysa robinioides has been identified as the new isoflavonoid 5 ,7 ,2 ',4 '-te trahydroxy-6-(3 ,3-dim ethylally l)isoflavanone (diphysolone). It is accom panied by sm aller quan tities o f d iphyso lone-4 ' (or 2 ')-0 -m e th y l ether (diphysolidone), and the known isoflavonoids 5 ,7 ,2 ',4 '-tetrahydroxy-8-(3 ,3-dim ethylally l)isoflavanone (kievitone) and 5 ,7 ,2 '-trihydroxy-4 '-m ethoxyisoflavanone (ferreirin).