Isolation and structure elucidation of qianhucoumarin A

Seven compounds were isolated from the traditional Chinese Medicine Qianhu, roots of Peucedanum praeruptorum Dunn. Their structures were identified as psoralen (Ⅱ), 5-methoxyp soralen (Ⅲ), 8-methoxypsoralen (Ⅳ), pteryxin (Ⅴ), peucedanocoumarin Ⅱ (Ⅵ), β-sitosterol (Ⅶ) and qianhucoumarin A (Ⅷ) by physico-chemical constants and spectral analyses (UV, IR, ~1HNMR, ~(13)CNMR, ELMS). Ⅷ is a new compound with the structure of 3' (R)-hydroxy-4'(R)-tigloyloxy-3',4'-dihydroseslin. Its absolute configurations were determined by chemical correlation with known compounds. Ⅱ, Ⅲ, Ⅳ and Ⅶ were first isolated from this plant.