Isolation and crystal structure of grilactone, a new guaianolide from Ferula oopoda
The chief constituent of the essential oils from the roots of the plant Ferula oopoda is the sesquiterpene guaianolide, grilactone, whose structure has been determined by an X-ray diffraction study. Crystals are orthorhombic, space group P212121 with four molecules in a cell of dimensions a= 9.90 (2), b= 14.98 (2), c= 8.74 (2)Å. The structure was refined by least squares to R 0.079. Grilactone has a cis-anti-cis-configuration at the ring junctions.