Separation and NMR studies on lignans of Raulinoa echinata

Investigation of the leaves of Raulinoa echinata Cowan (Rutaceae) has led t o the isolation of several furofuran (2,6-diaryl-3,7-dioxabicyclo[3.3.0]-oc tane) lignan derivatives, namely (+)-sesamin, (+)-eudesmin, (+)-methylpiper itol (= kobusin), (+)-piperitol-gamma,gamma -dimethylallylether and the cor responding epi compounds: (+)-asarinin, (+)-epieudesmin, (+)-methylxanthoxy lol, (+)-methylpluviatilol, (+)-xanthoxylol-gamma,gamma -dimethylallylether / and (+)-pluviatilol-gamma,gamma -dimethylallylether. This is the first re port of the chromatographic separation of the epimers (+)-methylxanthoxylol /(+)-methylpluviatilol and (+)-xanthoxylol-gamma,gamma -dimethylallylether/ (+)-pluviatilol-gamma,gamma -dimethylallylether and of their NMR nOe differ ence studies. Copyright (C) 2001 John Wiley & Sons, Ltd.