PRENYLCOUMARINS FROM MURRAYA-PANICULATA VAR OMPHALOCARPA (RUTACEAE) -THE ABSOLUTE-CONFIGURATION OF SIBIRICIN, MEXOTICIN AND OMPHAMURIN

Three new prenylcoumarins, murpaniculol senecioate, 5-methoxymurrayati n and omphamurin isovalerate were isolated from the leaves of Murraya paniculata var, omphalocarpa (Rutaceae), together with six known couma rins, paniculatin, (-)-sibiricin, 5,7-dimethoxy-8-(3'-methyl-2'-oxobut yl)coumarin, (-)-mexoticin, omphamurin and omphalocarpin, Their struct ures were characterized on the basis of spectroscopic evidence, The ab solute configuration of omphamurin at the C-2' position has been deter mined to be S by Horeau's method, The absolute stereochemistry of (-)- mexoticin and (-)-sibiricin has also been established by their chemica l correlation with omphamurin.