Five furanocoumarins including a new one were isolated from the root of Ang
elica dahurica by repeated silica gel column chromatography. Their chemical
structures were determined to be isoimperatorin (1), oxypeucedanin hydrate
-3"-butyl ether (2), imperatorin (3), knidilin (4), and oxypeucedanin hydra
te (5). This represents the first study in which the compound 2 has been is
olated and identified. The long-range coupling ((5)J) in the H-1-NMR spectr
um observed in the linear furanocoumarin skeleton was also investigated in
detail.