Isolation And Structure Elucidation Of 5,7-disubstituted Simple Coumarins In The Fruits Of Heracleum Mantegazzianum.

In addition to bergapten ( 1 ), xanthotoxin ( 2 ), isopimpinellin ( 3 ), imperatorin ( 4 ), and pimpinellin ( 5 ), for the first time 5,7-disubstituted simple coumarins, limettin (5,7-dimethoxycoumarin) ( 6 ) and a new compound 5-methoxy-7-(3,3-dimethylalliloxy)-coumarin ( 7 ), have been isolated from the fruits of Heracleum mantegazzianum Somm. et Lev. The new compound 7 is a derivative of anisocoumarin B. The structures of 6 and 7 were determined on the basis of 1D and 2D NMR spectra.