Revised structures for senegalensin and euchrenone b(10)

Two prenylated isoflavones (1 and 2) with a hydroxyisopropyldihydrofuran mo iety have been isolated from the wood of Erythrina suberosa var. glabrescen ce. The structure of compound I was in agreement with that of the previousl y reported senegalensin, isolated from the stem bark of Erythrina senegalen sis. The structure of senegalensin was revised from structure 2 to structur e I by spectroscopic means. Compound 2, the regioisomer of 1, was confirmed as euchrenone b(10) by comparison with the spectral data of the reported e uchrenone b(10), isolated from the roots of Euchresta horsfieldii. The stru cture of 2 was established by 2D NMR spectroscopic analysis and by the X-ra y crystallographic analysis of its p-bromobenzoyl derivative (2b).