1-[(1S,6R,7S,9R)-8,8-Di­bromo-5,5,9-tri­methyl­tri­cyclo­[4.4.0.1^7,9]decan-1-yl]ethanone

The title compound, C₁₆H₂₄Br₂O, was synthesized by three steps from β-himachalene (3,5,5,9-tetra­methyl-2,4a,5,6,7,8-hexa­hydro-1H-benzo­cyclo­heptene), which was isolated from essential oil of the Atlas cedar cedrus atlantica. The asymmetric unit contains two independent mol­ecules with almost identical conformations. Each mol­ecule is built up from two fused six-membered rings, one having a chair conformation and the other a boat conformation, and an additional three-membered ring arising from the reaction of himachalene with di­bromo­carbene. In the crystal, there are no significant intermolecular interactions present. The absolute structure of the title compound was confirmed by resonance scattering.

12-{[4-(4-Bromo­phen­yl)piperazin-1-yl]meth­yl}-9α-hy­droxy-4,8-dimethyl-3,14-dioxatri­cyclo­[9.3.0.0^2,4]tetra­dec-7-en-13-one

The title compound, C₂₅H₃₃BrN₂O₄, was synthesized from 9α-hy­droxy­parthenolide (9α-hy­droxy-4,8-dimethyl-12-methylen-3,14-dioxa-tri­cyclo­[9.3.0.0^2,4]tetra­dec-7-en-13-one), which was isolated from the chloro­form extract of the aerial parts of Anvillea radiata. The mol­ecule is built up from two fused five- and ten-membered rings with an additional ep­oxy ring system and a bromo­phenyl­piperazine group as a substituent. The ten-membered ring adopts an approximate chair–chair–chair conformation, while the piperazine ring displays a chair conformation and the five-membered ring shows an envelope conformation with the C atom closest to the hy­droxy group forming the flap. An intra­molecular O—H...N hydrogen bond stabilizes the mol­ecular conformation. The crystal packing features C—H...O hydrogen bonds, which link the mol­ecules into zigzag chains running along the b-axis direction.

(1R,4R,6S,7R)-5,5-Di­bromo-1,4,8,8-tetra­methyl­tri­cyclo­[5.4.1.0^4,6]dodecan-12-one

The title compound, C₁₆H₂₄Br₂O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetra­methyl-2,4a,5,6,7,8-hexa­hydro-1H-benzo­cyclo­heptene), which was isolated from Atlas cedar (Cedrus atlantica). The asymmetric unit contains two independent mol­ecules with similar conformations. Each mol­ecule is built up from two fused seven-membered rings and an additional three-membered ring. In both mol­ecules, one of the seven-membered rings has a chair conformation, whereas the other displays a screw-boat conformation.

9α-Hy­droxy-12-{[4-(4-hy­droxy­phen­yl)piperazin-1-yl]meth­yl}-4,8-dimethyl-3,14-dioxatri­cyclo­[9.3.0.0^2,4]tetra­dec-7-en-13-one

The title compound, C₂₅H₃₄N₂O₅, was synthesized from 9α-hy­droxy­parthenolide (9α-hy­droxy-4,8-dimethyl-12-methylen-3, 14-dioxa-tri­cyclo­[9.3.0.0^2,4]tetra­dec-7-en-13-one), which in turn was isolated from the chloro­form extract of the aerial parts of Anvillea radiata. The mol­ecule comprises a ten-membered ring fused to a five-membered ring with an additional ep­oxy ring system fused to the ten-membered ring. The five-membered ring also carries a 4-hy­droxy­phenyl-piperazin-1-ylmethyl substituent. The ten-membered ring adopts an approximate chair–chair conformation, while the piperazine ring displays a chair conformation and the five-membered ring shows an envelope conformation with the C atom closest to the hy­droxy group forming the flap. Two C atoms in the phenyl ring and the O atom of the hydroxyl group are disordered over two sites, with an occupancy ratio of 0.53 (5):0.47 (5). An intra­molecular O—H...N hydrogen-bond stabilizes the mol­ecular conformation. In the crystal, C—H...O hydrogen bonds link the mol­ecules into zigzag chains running along the a-axis direction.

(1S,2R,3S,6S,7R)-3,7,11,11-Tetra­methyl-6,7-epoxybi­cyclo­[5.4.0]undecane-2-ol

The title compound, C₁₅H₂₆O₂, was synthesized from β-himachalene (3,5,5,9-tetra­methyl-2,4a,5,6,7,8-hexa­hydro-1H-benzo­cyclo­heptene), which was isolated from the Atlas cedar (cedrus atlantica). The mol­ecule is built up from a seven-membered ring to which a six- and a three-membered ring are fused. The seven- and six-membered rings each have a twist-boat conformation. In the crystal, O—H...O hydrogen bonds link the mol­ecules into zigzag chains running along the b-axis direction.