Date Published: August 01, 2012
Publisher: International Union of Crystallography
Author(s): Ahmed Benharref, Lahcen El Ammari, Essêdiya Lassaba, Najia Ourhriss, Moha Berraho.
The title compound, C16H24Br2, was synthesized from β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The molecule is built up from two fused six- and seven-membered rings and an additional three-membered ring from the reaction of β-himachalene with dibromocarbene. The six-membered ring shows a screw-boat conformation, whereas the seven-membered ring displays a boat conformation; the dihedral angle between the mean planes through the rings is 57.9 (4)°. The absolute structure was established unambiguously from anomalous dispersion effects.
For the isolation of β-himachalene, see: Joseph & Dev (1968 ▶); Plattier & Teiseire (1974 ▶). For the reactivity of this sesquiterpene, see: Lassaba et al. (1997 ▶); Chekroun et al. (2000 ▶); El Jamili et al. (2002 ▶); Sbai et al. (2002 ▶); Dakir et al. (2004 ▶). For its biological activity, see: Daoubi et al. (2004 ▶). For conformational analysis, see: Cremer & Pople (1975 ▶).