New Bisabolane Sesquiterpenes and Coumarin from Leontopodium longifolium

From the roots of Leontopotium longifolium , three new bisabolane sesquiterpenes, rel ‐(1 S ,4 R ,5 S ,6 R )‐4,5‐diacetoxy‐6‐[( R )‐1,5‐dimethylhexa‐3,5‐dienyl]‐3‐methylcyclohex‐2‐enyl ( Z )‐2‐methylbut‐2‐enoate ( 1 ), rel ‐(1 S , 4R ,5 S ,6 R )‐4,5‐diacetoxy‐6‐[( R )‐5‐hydroxy‐1,5‐dimethylhex‐3‐enyl]‐3‐methylcyclohex‐2‐enyl ( Z )‐2‐methylbut‐2‐enoate ( 2 ), rel ‐(1 R ,2 S ,4 R ,5 S )‐4‐acetoxy‐2‐[( R )‐5‐hydroxy‐1,5‐dimethylhex‐3‐enyl]‐5‐methylcyclohexyl ( Z )‐2‐methylbut‐2‐enoate ( 3 ), and a new coumarin, 2,3‐dihydro‐5‐hydroxy‐2‐(1‐methylethenyl)‐7 H ‐pyrano[2,3‐ g ][1,4]benzodioxin‐7‐one ( 4 ) together with nine known compounds have been isolated. The structures of these compounds were established by spectroscopic methods. Compounds 1 and 2 exhibited moderate cytotoxic activities against human promyelocytic leukemia (HL‐60) cells.