Sesquiterpenoids. Part XV. Conformation of humulene: X-ray analysis of the crystal structure of humulene diepoxide

Abstract

The crystal structure of the title compound has been elucidated by the symbolic addition procedure and the eleven-membered carbocyclic ring of the sesquiterpene shown to have the conformation previously reported for the humulene molecule in the humulene–silver nitrate adduct, the mean deviation between corresponding torsion angles in the two molecules being 8°. Crystallographic data for the diepoxide are a= 15·265(10), b= 5·794(3), c= 16·055(8)Å, β= 103° 24(4)′, Z= 4, space group P2₁/c. Diffractometer (Mo-K_α radiation) and photographic (Cu-K_α radiation) intensity data were merged to give 1127 |F_o| values, and least-squares adjustment of the atomic co-ordinates and thermal parameters converged at R 7·5%.