organic compounds
(1S,2S,4R)-3,3-Dichloro-4,8,12,12-tetramethyltricyclo[5.5.0.02,4]dodeca-6,8-diene
aLaboratoire de Chimie des Substances Naturelles, "Unité Associé au CNRST (URAC16)", Faculté des Sciences Semlalia, BP 2390 Bd My Abdellah, 40000 Marrakech, Morocco, and bLaboratoire de Chimie du Solide Appliquée, Faculté des Sciences, Avenue Ibn Battouta BP 1014 Rabat, Morocco
*Correspondence e-mail: abenharref@yahoo.fr
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)°.
Related literature
For background to himachalene derivatives, see: Plattier & Teiseire (1974); Sbai et al. (2002). For ring puckering analysis, see: Cremer & Pople (1975). For the synthesis of the title compound, see: Lassaba et al. (1997). For the reactivity of this sesquiterpene, see: El Jamili et al. (2002; Sbai et al. (2002). For the olfactive properties of β-himachalene, see: Benharref et al. (1991); Bisarya & Dev (1968); Chekroun et al. (2000).
Experimental
Crystal data
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Data collection: APEX2 (Bruker, 2009); cell SAINT-Plus (Bruker, 2009); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supporting information
https://doi.org/10.1107/S1600536810034070/er2079sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810034070/er2079Isup2.hkl
100 mg (0,33 mm l) of the isomer, (1S,2R,7S,8S,10R)-9,9-dichloro- 1,2-epoxy-2,6,6,10- tetramethyl-tricyclo[5,5,0,08,10]dodecane, dissolved in 20 ml of dichloromethane and then treated with a stream of gaseous hydrochloric acid at 0° for 5 minutes. After concentration of solvent, the residue obtained was chromatgraphed on silica gel impregnated with silver nitrate (10%) with hexane as eluent.
Except H3 and H12, all H atoms were fixed geometrically and treated as riding with C—H = 0.96 Å (methyl),0.97 Å (methylene), 0.98Å (methine) with Uiso(H) = 1.2Ueq(methylene, methine) or Uiso(H) = 1.5Ueq(methyl).
Our work lies within the framework of the valorization of the most abundant essential oils in Morocco, such as Cedrus atlantica. This oil is made up mainly (75%) of bicyclic sesquiterpenes hydrocarbons, among which is found the compound, β-himachalene (Bisarya & Dev, 1968; Plattier & Teiseire, 1974). The reactivity of this sesquiterpene has been studied extensively by our team (El Jamili et al., 2002; Sbai et al., 2002) in order to prepare new products having olfactive proprieties suitable for the perfume or cosmetics industry. Thus, the action of one equivalent of meta-chloroperbenzoïc acide (m-CPBA) on, β- himachalène gives in quantitative yields the monoepoxyde (Benharref et al., 1991; Chekroun et al., 2000). The treatement of this monoepoxyde with dichlorocarbene, generated in situ from chloroform and in the presence of sodium hydroxide as base and n-benzyltriethylammonium chloride as catalyst, give a mixtrure of two (1S,2R,7S,8S,10R) -9,9-dichloro-1,2- epoxy-2,6,6,10-tetramethyl-tricyclo[5,5,0,08,10]dodecane and (1S,2R,7S,8R,10S) -9,9-dichloro-1,2-epoxy-2,6,6,10-tetramethyl- tricyclo[5,5,0,08,10] dodecane (Lassaba et al., 1997). Also in order to prepare products with high added value, we have treated the isomer (1S,2R,7S,8S,10R) -9,9-dichloro-1,2- epoxy-2,6,6,10-tetramethyl-tricyclo[5,5,0,08,10] dodecane (I) by hydrochloric acid gas and we got one sesquiterpene dichloro-hydrocarbure (II) in yield 75%. The molecule is built up from two fused six-and seven-membered rings(Fig.1). The six-membered ring has a perfect chair conformation, with as indicated by the total puckering amplitude QT = 0.2385 (2)Å and spherical polar angle θ= 99.60 (2)° with φ -117.07 (2)°, whereas the seven-membered ring display a screw boat conformation with QT = 0.9566 (2) Å, θ = 68.84 (2)°, φ2 = -112.42 (1)° and φ3 = 142.26 (3)° (Cremer & Pople, 1975). Owing to the presence of the Cl atoms, the could be fully confirmed to be C7(S), C8(S) and C10(R) (Flack & Bernardinelli, 2000).
For background to himachalene derivatives, see: Plattier & Teiseire (1974); Sbai et al. (2002). For ring puckering analysis, see: Cremer & Pople (1975). For the synthesis of the title compound, see: Lassaba et al. (1997). For the reactivity of this sesquiterpene, see: El Jamili et al. (2002; Sbai et al. (2002). For the olfactive properties of β-himachalene, see: Benharref et al. (1991); Bisarya & Dev (1968); Chekroun et al. (2000).
Data collection: APEX2 (Bruker, 2009); cell
SAINT-Plus (Bruker, 2009); data reduction: SAINT-Plus (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXS97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).C16H22Cl2 | F(000) = 608 |
Mr = 285.24 | Dx = 1.271 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 10992 reflections |
a = 7.4356 (17) Å | θ = 1.7–28.4° |
b = 8.3124 (18) Å | µ = 0.42 mm−1 |
c = 24.108 (6) Å | T = 298 K |
V = 1490.1 (6) Å3 | Prism, colourless |
Z = 4 | 0.27 × 0.18 × 0.12 mm |
Bruker X8 APEXII CCD area-detector diffractometer | 3282 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.026 |
Graphite monochromator | θmax = 28.4°, θmin = 1.7° |
φ and ω scans | h = −7→9 |
10992 measured reflections | k = −8→11 |
3691 independent reflections | l = −32→28 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.032 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.096 | w = 1/[σ2(Fo2) + (0.0579P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.11 | (Δ/σ)max = 0.001 |
3691 reflections | Δρmax = 0.34 e Å−3 |
175 parameters | Δρmin = −0.29 e Å−3 |
0 restraints | Absolute structure: Flack (1985), 1535 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.06 (6) |
C16H22Cl2 | V = 1490.1 (6) Å3 |
Mr = 285.24 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 7.4356 (17) Å | µ = 0.42 mm−1 |
b = 8.3124 (18) Å | T = 298 K |
c = 24.108 (6) Å | 0.27 × 0.18 × 0.12 mm |
Bruker X8 APEXII CCD area-detector diffractometer | 3282 reflections with I > 2σ(I) |
10992 measured reflections | Rint = 0.026 |
3691 independent reflections |
R[F2 > 2σ(F2)] = 0.032 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.096 | Δρmax = 0.34 e Å−3 |
S = 1.11 | Δρmin = −0.29 e Å−3 |
3691 reflections | Absolute structure: Flack (1985), 1535 Friedel pairs |
175 parameters | Absolute structure parameter: −0.06 (6) |
0 restraints |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.6213 (2) | 0.33418 (19) | 0.89982 (6) | 0.0375 (3) | |
C2 | 0.4484 (2) | 0.3173 (2) | 0.92944 (6) | 0.0476 (4) | |
C3 | 0.3427 (3) | 0.4400 (3) | 0.94246 (7) | 0.0551 (5) | |
C4 | 0.3834 (3) | 0.6154 (3) | 0.93795 (8) | 0.0588 (5) | |
H4A | 0.3146 | 0.6730 | 0.9658 | 0.071* | |
H4B | 0.3451 | 0.6535 | 0.9018 | 0.071* | |
C5 | 0.5809 (2) | 0.6534 (2) | 0.94551 (7) | 0.0514 (4) | |
H5A | 0.6290 | 0.5834 | 0.9741 | 0.062* | |
H5B | 0.5919 | 0.7633 | 0.9587 | 0.062* | |
C6 | 0.6957 (2) | 0.63474 (18) | 0.89326 (6) | 0.0405 (3) | |
C7 | 0.6413 (2) | 0.47755 (17) | 0.86197 (6) | 0.0341 (3) | |
H7 | 0.5234 | 0.4970 | 0.8451 | 0.041* | |
C8 | 0.7727 (2) | 0.44941 (18) | 0.81513 (6) | 0.0384 (3) | |
H8 | 0.8138 | 0.5487 | 0.7973 | 0.046* | |
C9 | 0.7663 (2) | 0.30866 (19) | 0.77693 (7) | 0.0427 (3) | |
C10 | 0.9167 (2) | 0.3203 (2) | 0.81854 (7) | 0.0438 (3) | |
C11 | 0.9108 (2) | 0.2114 (2) | 0.86840 (8) | 0.0497 (4) | |
H11A | 0.9257 | 0.1014 | 0.8558 | 0.060* | |
H11B | 1.0127 | 0.2368 | 0.8920 | 0.060* | |
C12 | 0.7456 (3) | 0.2200 (2) | 0.90240 (7) | 0.0457 (4) | |
C13 | 1.1028 (3) | 0.3568 (3) | 0.79848 (9) | 0.0628 (5) | |
H13A | 1.1600 | 0.2590 | 0.7867 | 0.094* | |
H13B | 1.1712 | 0.4044 | 0.8280 | 0.094* | |
H13C | 1.0966 | 0.4304 | 0.7679 | 0.094* | |
C14 | 0.8912 (3) | 0.6291 (2) | 0.91128 (8) | 0.0546 (4) | |
H14A | 0.9119 | 0.5336 | 0.9328 | 0.082* | |
H14B | 0.9181 | 0.7221 | 0.9334 | 0.082* | |
H14C | 0.9673 | 0.6280 | 0.8791 | 0.082* | |
C15 | 0.6651 (3) | 0.7795 (2) | 0.85566 (8) | 0.0573 (5) | |
H15A | 0.7378 | 0.7690 | 0.8229 | 0.086* | |
H15B | 0.6978 | 0.8761 | 0.8750 | 0.086* | |
H15C | 0.5406 | 0.7847 | 0.8453 | 0.086* | |
C16 | 0.3883 (3) | 0.1489 (3) | 0.94230 (11) | 0.0727 (6) | |
H16A | 0.4725 | 0.0996 | 0.9673 | 0.109* | |
H16B | 0.3825 | 0.0876 | 0.9086 | 0.109* | |
H16C | 0.2716 | 0.1518 | 0.9593 | 0.109* | |
Cl1 | 0.59995 (6) | 0.16140 (5) | 0.781164 (18) | 0.05350 (13) | |
Cl2 | 0.81596 (8) | 0.34714 (7) | 0.706600 (17) | 0.06577 (16) | |
H3 | 0.223 (3) | 0.414 (3) | 0.9587 (9) | 0.074 (6)* | |
H12 | 0.732 (3) | 0.127 (3) | 0.9270 (9) | 0.064 (6)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0388 (7) | 0.0457 (7) | 0.0281 (6) | −0.0004 (7) | 0.0008 (5) | −0.0004 (6) |
C2 | 0.0430 (9) | 0.0676 (11) | 0.0323 (7) | −0.0041 (8) | 0.0017 (6) | 0.0061 (7) |
C3 | 0.0393 (9) | 0.0868 (13) | 0.0391 (9) | −0.0009 (9) | 0.0065 (7) | −0.0031 (9) |
C4 | 0.0457 (10) | 0.0781 (12) | 0.0526 (10) | 0.0142 (9) | 0.0084 (8) | −0.0187 (9) |
C5 | 0.0500 (9) | 0.0632 (10) | 0.0411 (8) | 0.0055 (9) | −0.0002 (7) | −0.0196 (8) |
C6 | 0.0404 (8) | 0.0440 (8) | 0.0370 (7) | 0.0023 (7) | −0.0012 (6) | −0.0080 (6) |
C7 | 0.0324 (7) | 0.0403 (7) | 0.0297 (6) | 0.0027 (6) | −0.0007 (5) | −0.0020 (5) |
C8 | 0.0422 (8) | 0.0404 (7) | 0.0326 (7) | −0.0017 (6) | 0.0054 (6) | −0.0022 (6) |
C9 | 0.0434 (8) | 0.0512 (8) | 0.0334 (7) | −0.0048 (6) | 0.0071 (6) | −0.0074 (6) |
C10 | 0.0374 (8) | 0.0520 (8) | 0.0420 (8) | 0.0002 (7) | 0.0066 (6) | −0.0116 (7) |
C11 | 0.0441 (9) | 0.0517 (9) | 0.0532 (10) | 0.0111 (7) | −0.0005 (8) | −0.0033 (7) |
C12 | 0.0526 (10) | 0.0458 (8) | 0.0388 (8) | 0.0016 (7) | −0.0013 (7) | 0.0033 (7) |
C13 | 0.0432 (9) | 0.0831 (13) | 0.0621 (11) | −0.0044 (10) | 0.0113 (8) | −0.0171 (11) |
C14 | 0.0431 (9) | 0.0663 (11) | 0.0545 (10) | −0.0054 (9) | −0.0050 (8) | −0.0144 (8) |
C15 | 0.0744 (14) | 0.0392 (8) | 0.0583 (11) | 0.0027 (9) | −0.0033 (10) | −0.0024 (8) |
C16 | 0.0590 (12) | 0.0815 (13) | 0.0776 (14) | −0.0113 (12) | 0.0084 (11) | 0.0310 (12) |
Cl1 | 0.0529 (2) | 0.0574 (2) | 0.0502 (2) | −0.0120 (2) | −0.00032 (18) | −0.00975 (19) |
Cl2 | 0.0750 (3) | 0.0874 (3) | 0.0349 (2) | −0.0115 (3) | 0.0142 (2) | −0.0107 (2) |
C1—C12 | 1.326 (2) | C9—C10 | 1.505 (2) |
C1—C2 | 1.477 (2) | C9—Cl1 | 1.7433 (16) |
C1—C7 | 1.508 (2) | C9—Cl2 | 1.7645 (17) |
C2—C3 | 1.326 (3) | C10—C13 | 1.497 (2) |
C2—C16 | 1.502 (3) | C10—C11 | 1.505 (3) |
C3—C4 | 1.493 (3) | C11—C12 | 1.479 (3) |
C3—H3 | 1.00 (3) | C11—H11A | 0.9700 |
C4—C5 | 1.513 (3) | C11—H11B | 0.9700 |
C4—H4A | 0.9700 | C12—H12 | 0.98 (2) |
C4—H4B | 0.9700 | C13—H13A | 0.9600 |
C5—C6 | 1.530 (2) | C13—H13B | 0.9600 |
C5—H5A | 0.9700 | C13—H13C | 0.9600 |
C5—H5B | 0.9700 | C14—H14A | 0.9600 |
C6—C14 | 1.519 (2) | C14—H14B | 0.9600 |
C6—C15 | 1.524 (2) | C14—H14C | 0.9600 |
C6—C7 | 1.562 (2) | C15—H15A | 0.9600 |
C7—C8 | 1.511 (2) | C15—H15B | 0.9600 |
C7—H7 | 0.9800 | C15—H15C | 0.9600 |
C8—C9 | 1.490 (2) | C16—H16A | 0.9600 |
C8—C10 | 1.518 (2) | C16—H16B | 0.9600 |
C8—H8 | 0.9800 | C16—H16C | 0.9600 |
C12—C1—C2 | 121.04 (16) | C8—C9—Cl2 | 116.42 (12) |
C12—C1—C7 | 121.66 (14) | C10—C9—Cl2 | 118.25 (11) |
C2—C1—C7 | 116.97 (14) | Cl1—C9—Cl2 | 109.39 (9) |
C3—C2—C1 | 123.86 (17) | C13—C10—C11 | 114.00 (16) |
C3—C2—C16 | 119.48 (18) | C13—C10—C9 | 118.97 (15) |
C1—C2—C16 | 116.59 (17) | C11—C10—C9 | 118.17 (15) |
C2—C3—C4 | 127.88 (17) | C13—C10—C8 | 119.41 (16) |
C2—C3—H3 | 117.2 (14) | C11—C10—C8 | 116.60 (13) |
C4—C3—H3 | 114.8 (13) | C9—C10—C8 | 59.03 (10) |
C3—C4—C5 | 113.09 (17) | C12—C11—C10 | 115.96 (15) |
C3—C4—H4A | 109.0 | C12—C11—H11A | 108.3 |
C5—C4—H4A | 109.0 | C10—C11—H11A | 108.3 |
C3—C4—H4B | 109.0 | C12—C11—H11B | 108.3 |
C5—C4—H4B | 109.0 | C10—C11—H11B | 108.3 |
H4A—C4—H4B | 107.8 | H11A—C11—H11B | 107.4 |
C4—C5—C6 | 114.91 (14) | C1—C12—C11 | 126.00 (17) |
C4—C5—H5A | 108.5 | C1—C12—H12 | 121.5 (13) |
C6—C5—H5A | 108.5 | C11—C12—H12 | 112.4 (13) |
C4—C5—H5B | 108.5 | C10—C13—H13A | 109.5 |
C6—C5—H5B | 108.5 | C10—C13—H13B | 109.5 |
H5A—C5—H5B | 107.5 | H13A—C13—H13B | 109.5 |
C14—C6—C15 | 109.72 (16) | C10—C13—H13C | 109.5 |
C14—C6—C5 | 107.57 (14) | H13A—C13—H13C | 109.5 |
C15—C6—C5 | 109.07 (14) | H13B—C13—H13C | 109.5 |
C14—C6—C7 | 111.10 (13) | C6—C14—H14A | 109.5 |
C15—C6—C7 | 109.56 (13) | C6—C14—H14B | 109.5 |
C5—C6—C7 | 109.78 (13) | H14A—C14—H14B | 109.5 |
C1—C7—C8 | 113.17 (12) | C6—C14—H14C | 109.5 |
C1—C7—C6 | 113.22 (12) | H14A—C14—H14C | 109.5 |
C8—C7—C6 | 108.85 (12) | H14B—C14—H14C | 109.5 |
C1—C7—H7 | 107.1 | C6—C15—H15A | 109.5 |
C8—C7—H7 | 107.1 | C6—C15—H15B | 109.5 |
C6—C7—H7 | 107.1 | H15A—C15—H15B | 109.5 |
C9—C8—C7 | 124.25 (13) | C6—C15—H15C | 109.5 |
C9—C8—C10 | 60.05 (10) | H15A—C15—H15C | 109.5 |
C7—C8—C10 | 121.66 (13) | H15B—C15—H15C | 109.5 |
C9—C8—H8 | 113.6 | C2—C16—H16A | 109.5 |
C7—C8—H8 | 113.6 | C2—C16—H16B | 109.5 |
C10—C8—H8 | 113.6 | H16A—C16—H16B | 109.5 |
C8—C9—C10 | 60.92 (11) | C2—C16—H16C | 109.5 |
C8—C9—Cl1 | 122.54 (11) | H16A—C16—H16C | 109.5 |
C10—C9—Cl1 | 122.22 (12) | H16B—C16—H16C | 109.5 |
Experimental details
Crystal data | |
Chemical formula | C16H22Cl2 |
Mr | 285.24 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 298 |
a, b, c (Å) | 7.4356 (17), 8.3124 (18), 24.108 (6) |
V (Å3) | 1490.1 (6) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.42 |
Crystal size (mm) | 0.27 × 0.18 × 0.12 |
Data collection | |
Diffractometer | Bruker X8 APEXII CCD area-detector |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10992, 3691, 3282 |
Rint | 0.026 |
(sin θ/λ)max (Å−1) | 0.668 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.096, 1.11 |
No. of reflections | 3691 |
No. of parameters | 175 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.34, −0.29 |
Absolute structure | Flack (1985), 1535 Friedel pairs |
Absolute structure parameter | −0.06 (6) |
Computer programs: APEX2 (Bruker, 2009), SAINT-Plus (Bruker, 2009), SHELXS97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
Acknowledgements
The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.
References
Benharref, A., Chekroun, A. & Lavergne, J. P. (1991). Bull. Soc. Chim. Fr. 128, 738–741. Google Scholar
Bisarya, S. C. & Dev, S. (1968). Tetrahedron, 24, 3861–3867. CrossRef CAS Web of Science Google Scholar
Bruker (2009). APEX2 and SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Chekroun, A., Jarid, A., Benharref, A. & Boutalib, A. (2000). J. Org. Chem. 65, 4431–4434. Web of Science CrossRef PubMed CAS Google Scholar
Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358. CrossRef CAS Web of Science Google Scholar
El Jamili, H., Auhmani, A., Dakir, M., Lassaba, E., Benharref, A., Pierrot, M., Chiaroni, A. & Riche, C. (2002). Tetrahedron Lett. 43, 6645–6648. CAS Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838. CrossRef CAS IUCr Journals Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Lassaba, E., Chekroun, A., Benharref, A., Chiaroni, A., Riche, C. & Lavergne, J.-P. (1997). Bull. Soc. Chim. Belg. 106, 281–288. CAS Google Scholar
Plattier, M. & Teiseire, P. (1974). Recherche, 19, 131–144. CAS Google Scholar
Sbai, F., Dakir, M., Auhmani, A., El Jamili, H., Akssira, M., Benharref, A., Kenz, A. & Pierrot, M. (2002). Acta Cryst. C58, o518–o520. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
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Our work lies within the framework of the valorization of the most abundant essential oils in Morocco, such as Cedrus atlantica. This oil is made up mainly (75%) of bicyclic sesquiterpenes hydrocarbons, among which is found the compound, β-himachalene (Bisarya & Dev, 1968; Plattier & Teiseire, 1974). The reactivity of this sesquiterpene has been studied extensively by our team (El Jamili et al., 2002; Sbai et al., 2002) in order to prepare new products having olfactive proprieties suitable for the perfume or cosmetics industry. Thus, the action of one equivalent of meta-chloroperbenzoïc acide (m-CPBA) on, β- himachalène gives in quantitative yields the monoepoxyde (Benharref et al., 1991; Chekroun et al., 2000). The treatement of this monoepoxyde with dichlorocarbene, generated in situ from chloroform and in the presence of sodium hydroxide as base and n-benzyltriethylammonium chloride as catalyst, give a mixtrure of two diastereoisomers: (1S,2R,7S,8S,10R) -9,9-dichloro-1,2- epoxy-2,6,6,10-tetramethyl-tricyclo[5,5,0,08,10]dodecane and (1S,2R,7S,8R,10S) -9,9-dichloro-1,2-epoxy-2,6,6,10-tetramethyl- tricyclo[5,5,0,08,10] dodecane (Lassaba et al., 1997). Also in order to prepare products with high added value, we have treated the isomer (1S,2R,7S,8S,10R) -9,9-dichloro-1,2- epoxy-2,6,6,10-tetramethyl-tricyclo[5,5,0,08,10] dodecane (I) by hydrochloric acid gas and we got one sesquiterpene dichloro-hydrocarbure (II) in yield 75%. The molecule is built up from two fused six-and seven-membered rings(Fig.1). The six-membered ring has a perfect chair conformation, with as indicated by the total puckering amplitude QT = 0.2385 (2)Å and spherical polar angle θ= 99.60 (2)° with φ -117.07 (2)°, whereas the seven-membered ring display a screw boat conformation with QT = 0.9566 (2) Å, θ = 68.84 (2)°, φ2 = -112.42 (1)° and φ3 = 142.26 (3)° (Cremer & Pople, 1975). Owing to the presence of the Cl atoms, the absolute configuration could be fully confirmed to be C7(S), C8(S) and C10(R) (Flack & Bernardinelli, 2000).