Coumarins from Musineon divaricatum

A chemical investigation of Musineon divaricatum has resulted in the isolation of 19 coumarins, five of which are novel compounds; 18 are khellactone derivatives. The coumarins were isolated from the crude extracts by a combination of adsorption chromatography, gel permeation and HPLC; the more successful HPLC separations utilized a nitrile bonded phase column. The structures were determined by ¹H NMR and mass spectral studies and by comparisons with literature data. The relative configuration for the entire series was secured from ¹H NMR data, while the absolute configuration could be assigned with any certainty only in the cases of two of the compounds.