Studies on coumarins of a chinese drug "Qian-Hu"

From the ether-soluble fraction of methanolic extracts of a Chinese Drug "Bai-Hua Quian-Hu", the root of Peucedanum praeruptorum (Umbelliferae), four coumarin compounds, (+/-) praeruptorin A, (+) praeruptorin B (= (+) anomalin), Pd-III and Pd-Ib, were isolated. The chemical structures of Pd-III and Pd-Ib have been established to be (+) 3' ( S)-angeroyloxy-4' ( S)-isovaleryloxy-3', 4'-dihydroseselin and (+) 3' ( R)-angeroyloxy-4'-keto-3',4'-dihydroseselin, respectively. (13)C NMR spectra of these compounds are also discussed.