Constituents of the Egyptian Centaurea scoparia; Chlorinated Guaianolides of the Aerial Parts.

A new chlorine-containing guaianolide, chloroscoparin, was isolated from the ethanol extract of the aerial parts of CENTAUREA SCOPARIA Sieb. together with three known chlorine-containing guaianolides. The structures of the isolated compounds were elucidated by spectroscopic methods including (1)H-NMR-, 2D (1)H- (1)H COSY-, (13)C-NMR-, APT-, DEPT-, HETCOR-, long-range-HETCOR-, 2D INADEQUATE-, and mass spectra. The relative configuration was determined by 2D-NOESY studies. New NMR data for the known compounds are reported.