5,9-Dihy­droxy-9-methyl-3,6-dimethyl­ene-3a,4,5,6,6a,7,8,9,9a,9b-deca­hydro­azuleno[4,5-b]furan-2(3H)-one

The title compound, C15H20O4, was synthesized from 9α-hy­droxy­parthenolide (9α-hy­droxy-4,8-dimethyl-12-methyl­ene-3,14-dioxatricyclo­[9.3.0.02,4]tetra­dec-7-en-13-one), which was isolated from the chloro­form extract of the aerial parts of Anvillea radiata. The seven-membered ring has a chair conformation, while the five-membered rings display twisted conformations. The dihedral angle between the seven-membered ring and the lactone ring is 21.69 (10)°. In the crystal, mol­ecules are linked into chains propagating along the c axis by inter­molecular O—H⋯O hydrogen bonds; an intra­molecular O—H⋯O link also occurs

Methyl 2-(3a,8a-dimethyl-4-oxodeca­hydro­azulen-6-yl)acrylate

The title compound, C16H24O3, was synthesized from ilicic acid, which was isolated from the aerial part of Inula viscosa­ (L) Aiton [or Dittrichia viscosa­ (L) Greuter]. The asymmetric unit contains two independent mol­ecules, in each of which the seven-membered ring shows a chair conformation, whereas the five-membered ring presents disorder. In the two molecules, three C atoms in the five-membered ring are disordered over two positions with site-occupancy factors of 0.53/0.47 and 0.83/0.17. The dihedral angle between the two rings is different in the two mol­ecules [31.7 (3) and 47.7 (7)°]. The crystal structure is stabilized by weak inter­molecular C—H⋯O hydrogen-bond inter­actions

12-{[4-(2-Fluoro­phen­yl)piperazin-1-yl]­meth­yl}-9α-hy­droxy-4,8-dimethyl-3,14-dioxatricyclo­[9.3.0.02,4]tetra­dec-7-en-13-one

The title compound, C25H33FN2O4, was synthesized from 9α-hy­droxy­parthenolide (9α-hy­droxy-4,8-dimethyl-12-methyl­ene-3,14-dioxatricyclo­[9.3.0.02,4]tetra­dec-7-en-13-one), which was isolated from the chloro­form extract of the aerial parts of Anvillea radiata. The asymmetric unit contains two independent mol­ecules. In each mol­ecule, the ten-membered ring displays an approximative chair–chair conformation. Each of the piperazine rings adopts a perfect chair conformation, while both lactone rings show an envelope conformation, one with the C atom bearing the piperazin-1-ylmethyl group as the flap, the other with the junction C atom not attached to the ring O atom as the flap. The dihedral angles between the least-squares planes through the ten- and five-membered rings in the two mol­ecules are similar [19.1 (3) and 16.2 (3)°]. An intra­molecular O—H⋯N hydrogen bond stabilizes the mol­ecular conformation. The crystal packing is stabilized by C—H⋯O hydrogen bonds

10α-Hy­droxy-13-{[4-(4-meth­oxy­phen­yl)piperazin-1-yl]meth­yl}-4,9-dimethyl-3,8,15-trioxatetra­cyclo­[10.3.0.02,4.07,9]penta­decan-14-one

The title compound, C26H36N2O6, was synthesized from 9α-hy­droxy­parthenolide (9α-hy­droxy-4,8-dimethyl-12-methylen-3,14-dioxa-tricyclo­[9.3.0.02,4]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 fused five- and ten-membered rings with two additional ep­oxy ring systems and a meth­oxy­phenyl­piperazine group as a 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. The mol­ecular conformation is determined by an O—H⋯N hydrogen bond between the hy­droxy group and a piperazine N atom. The crystal structure is built up by weak C—H⋯O inter­actions

(±)-N-[4-Acetyl-5-methyl-5-(4-methyl­cyclo­hex-3-en­yl)-4,5-dihydro-1,3,4-thia­diazol-2-yl]acetamide

The new title thiadiazole compound, C14H21N3O2S, was semi-synthesized starting from 1-(4-methyl­cyclo­hex-3-en­yl)ethanone, a natural product isolated from Cedrus atlantica essential oil. The stereochemistry has been confirmed by single-crystal X-ray diffraction. The thia­diazo­line ring is roughly planar, although it may be regarded as having a half-chair conformation. The cyclo­hexenyl ring has a half-chair conformation. The most inter­esting feature is the formation of a pseudo-ring formed by four mol­ecules associated through N—H⋯O hydrogen bonds around a fourfold inversion axis, forming an R 4 4(28) motif

1-Isopropyl-4,7-dimethyl-2,8-dinitro­naphthalene

The title compound, C15H16N2O4, was synthesized from a mixture of α-himachalene (2-methyl­ene-6,6,9-trimethyl­bicyclo­[5.4.O1,7]undec-8-ene) and β-himachalene (2,6,6,9-tetra­methyl­bicyclo­[5.4.01,7]undeca-1,8-diene) which were isolated from an oil of the Atlas cedar (Cedrus atlantica). The asymmetric unit contains two independent mol­ecules. In each of the two mol­ecules, two O atoms of one nitro group are disordered over two sets of sites with site-occupancy factors of 0.636 (5):0.364 (5) and 0.832 (5):0.168 (5). The crystal structure features weak C—H⋯O hydrogen bonds

Crystal structure of (1S,2R,4R,9S,11S,-12R)-9α-hydroxy-4,8-dimethyl-12-[(thio-morpholin-4-yl)methyl]-3,14-dioxatri-cyclo[9.3.0.02,4]tetradec-7-en-13-one

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.Peer reviewedPublisher PD

(1S,2S,4R)-3,3-Dichloro-4,8,12,12-tetra­methyl­tricyclo­[5.5.0.02,4]dodeca-6,8-diene

The title compound, C16H22Cl2, a derivative of β-himachalene, was semi-synthesized from natural essential oils of Cedrus atlantica. The mol­ecule is built up from two fused six- and seven-membered rings. The six-membered ring has a perfect chair conformation, whereas the seven-membered ring displays a screw boat conformation; the dihedral angle between the rings is 46.48 (9)°

12-Anilinomethyl-9α-hy­droxy-4,8-dimethyl-3,14-dioxatricyclo­[9.3.0.02,4]tetra­dec-7-en-13-one

The title compound, C21H27NO4, was synthesized from 9α-hy­droxy­parthenolide, which was isolated from the chloro­form extract of the aerial parts of Anvillea radiata. The asymmetric unit contains two independent mol­ecules. In each, the ten-membered ring displays an approximative chair-chair conformation. Each of the five-membered rings adopts a flattened envelope conformation, the C(H)—C—C(H) atoms representing the flap lie out of the mean plane through the remaining four atoms by 0.443 (2) and 0.553 (2) Å. The dihedral angle between the least-squares planes through the ten- and five-membered rings in the two mol­ecules are similar [22.54 (17) and 23.39 (14)°]. In the crystal, mol­ecules are linked by O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds