Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807042596/fl2159sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807042596/fl2159Isup2.hkl |
CCDC reference: 663702
Key indicators
- Single-crystal X-ray study
- T = 173 K
- Mean (C-C) = 0.002 Å
- R factor = 0.041
- wR factor = 0.115
- Data-to-parameter ratio = 18.4
checkCIF/PLATON results
No syntax errors found
Alert level C ABSTY03_ALERT_1_C The _exptl_absorpt_correction_type has been given as none. However values have been given for Tmin and Tmax. Remove these if an absorption correction has not been applied. From the CIF: _exptl_absorpt_correction_T_min 0.961 From the CIF: _exptl_absorpt_correction_T_max 0.972 PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ?
Alert level G PLAT793_ALERT_1_G Check the Absolute Configuration of C1 = ... S PLAT793_ALERT_1_G Check the Absolute Configuration of C3 = ... S PLAT793_ALERT_1_G Check the Absolute Configuration of C5 = ... R PLAT793_ALERT_1_G Check the Absolute Configuration of C7 = ... R PLAT793_ALERT_1_G Check the Absolute Configuration of C9 = ... S PLAT793_ALERT_1_G Check the Absolute Configuration of C10 = ... R
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 2 ALERT level C = Check and explain 6 ALERT level G = General alerts; check 8 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
For similar structures, see: Flippen-Anderson et al. (1991); Linden et al. (2005); Kruger et al. (2005, 2006).
A solution of Pentacyclo[5.4.0.02,6.03,10.05,6]undecane-8,11-dione (20.0 g, 0.115 mol) in dry THF (200 ml) was added dropwise over 2 h to a stirred suspension of vinylmagnesium bromide under nitrogen at 0°C. After the addition had been completed, the external ice-water bath was removed, and the reaction mixture was allowed to warm gradually to room temperature while stirring under nitrogen for 24 h. The reaction was quenched via addition of saturated aqueous NH4Cl (until pH is 6~7), the layers were separated, and the aqueous layer was extracted with EtOAc (2 x 500 ml). The combined organic extracts were dried (Na2SO4) and filtered, and the filtrate was concentrated in vacuo. The residue was recrystallized from hexane, thereby affording pure (I) (27.0 g, 91%) as a colorless microcrystalline solid: m.p. 82–83 °C.
All hydrogen atoms were first located in the difference map then positioned geometrically and allowed to ride on their respective parent atoms.
The title compound (I) consists of a large apolar (lipophilic) hydrocarbon skeleton with polar dihydroxy units (Fig. 1). This unique compound is used as a starting molecule and derivatives thereof are coupled with desired peptides as potential HIV-1 protease inhibitors. A number of publications have focused on the molecular geometries of pentacycloundecane (PCU) cage derivatives (Flippen-Anderson et al., 1991; Linden et al., 2005; Kruger et al., 2005; Kruger et al., 2006). It has been reported that these compounds exhibit bond lengths deviating from the normal value of 1.54 Å. The shortening and elongation of specific C—C bonds in the cage molecule is also observed in (i) with the C—C bonds between C3—C4 & C4—C5 being the shortest (1.5237 (17) Å & 1.5256 (17) Å respectively) and the bonds between C1—C7 & C1—C2 being the longest (1.5712 (16) Å & 1.5626 (16) Å respectively). Interestingly the bonds between the cage and the alkene side chains (C11—C12 and C8—C14) are surprisingly shorter than expected value of C—C bonds (1.54 Å) with values of 1.5173 (16) Å and 1.5212 (15) Å respectively. The ethylene chains are in an energetically favorable conformation, with atoms C8, C11, C12, C13, C14 coplanar. Atoms C13 and C15 appear to be in a trans conformation with respect to each other. This allows the two hydroxyl groups to be in a favorable conformation for intra- and intermolecular hydrogen bonding.
In (I), the molecules pack in hydrogen-bonded bilayers. Both hydroxyl groups on the molecule participate in both intramolecular and intermolecular hydrogen bonding, each acting as a hydrogen bond donor and acceptor. Atom O2 interacts with atom O1 via H2A and atom O1 interacts with O2 of another cage molecule via H1A. Thus forming a hydrogen-bonded linear chain (Fig. 2). Because both the hydroxy groups of a molecule are involved in hydrogen bonding, molecules are connected in a linear fashion forming a sheet with alternating hydrogen bonding between the molecules. The linear sheets do not show any hydrogen bonding between the lipophilic parts of the bilayers but do show short contacts.
For similar structures, see: Flippen-Anderson et al. (1991); Linden et al. (2005); Kruger et al. (2005, 2006).
Data collection: SMART-NT (Bruker, 1998); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus (Bruker, 1999); program(s) used to solve structure: SHELXTL (Bruker, 1999); program(s) used to refine structure: SHELXTL (Bruker, 1999); molecular graphics: Mercury (Macrae et al., 2006) and WinGX (Farrugia, 1999); software used to prepare material for publication: SHELXTL (Bruker, 1999) and PLATON (Spek, 2003).
Fig. 1. The asymmetric unit of (I), showing the atomic numbering scheme and ellipsoids at the 50% probability level. | |
Fig. 2. Depiction of the intramolecular and intermolecular hydrogen bonding. |
C15H18O2 | F(000) = 496 |
Mr = 230.29 | Dx = 1.289 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 1016 reflections |
a = 6.9355 (5) Å | θ = 3.6–28.3° |
b = 21.3303 (13) Å | µ = 0.08 mm−1 |
c = 8.1859 (5) Å | T = 173 K |
β = 101.435 (3)° | Irregular, colourless |
V = 1186.95 (13) Å3 | 0.48 × 0.40 × 0.34 mm |
Z = 4 |
Bruker SMART CCD area-detector diffractometer | 2525 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.031 |
Graphite monochromator | θmax = 28.0°, θmin = 1.9° |
φ and ω scans | h = −9→9 |
15589 measured reflections | k = −28→28 |
2869 independent reflections | l = −10→10 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.115 | H-atom parameters constrained |
S = 1.08 | w = 1/[σ2(Fo2) + (0.0599P)2 + 0.3441P] where P = (Fo2 + 2Fc2)/3 |
2869 reflections | (Δ/σ)max < 0.001 |
156 parameters | Δρmax = 0.35 e Å−3 |
0 restraints | Δρmin = −0.20 e Å−3 |
C15H18O2 | V = 1186.95 (13) Å3 |
Mr = 230.29 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 6.9355 (5) Å | µ = 0.08 mm−1 |
b = 21.3303 (13) Å | T = 173 K |
c = 8.1859 (5) Å | 0.48 × 0.40 × 0.34 mm |
β = 101.435 (3)° |
Bruker SMART CCD area-detector diffractometer | 2525 reflections with I > 2σ(I) |
15589 measured reflections | Rint = 0.031 |
2869 independent reflections |
R[F2 > 2σ(F2)] = 0.041 | 0 restraints |
wR(F2) = 0.115 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.35 e Å−3 |
2869 reflections | Δρmin = −0.20 e Å−3 |
156 parameters |
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. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.93905 (16) | 0.33993 (5) | 0.24919 (14) | 0.0231 (2) | |
H1 | 1.0523 | 0.3101 | 0.2724 | 0.028* | |
C2 | 0.99718 (17) | 0.41041 (6) | 0.23947 (15) | 0.0269 (3) | |
H2 | 1.1400 | 0.4203 | 0.2495 | 0.032* | |
C3 | 0.85062 (18) | 0.44024 (5) | 0.09116 (15) | 0.0273 (3) | |
H3 | 0.9047 | 0.4482 | −0.0115 | 0.033* | |
C4 | 0.7748 (2) | 0.49790 (6) | 0.16851 (17) | 0.0323 (3) | |
H4A | 0.6623 | 0.5180 | 0.0934 | 0.039* | |
H4B | 0.8794 | 0.5292 | 0.2072 | 0.039* | |
C5 | 0.71320 (18) | 0.46260 (5) | 0.31196 (15) | 0.0275 (3) | |
H5 | 0.6537 | 0.4889 | 0.3903 | 0.033* | |
C6 | 0.90169 (17) | 0.42568 (5) | 0.39229 (15) | 0.0264 (3) | |
H6 | 0.9882 | 0.4445 | 0.4925 | 0.032* | |
C7 | 0.84341 (16) | 0.35538 (5) | 0.40315 (14) | 0.0225 (2) | |
H7 | 0.9050 | 0.3337 | 0.5090 | 0.027* | |
C8 | 0.61711 (16) | 0.35801 (5) | 0.36817 (13) | 0.0208 (2) | |
C9 | 0.58290 (16) | 0.40754 (5) | 0.22715 (14) | 0.0230 (2) | |
H9 | 0.4413 | 0.4196 | 0.1930 | 0.028* | |
C10 | 0.68068 (17) | 0.39180 (5) | 0.07136 (14) | 0.0234 (2) | |
H10 | 0.5858 | 0.3964 | −0.0372 | 0.028* | |
C11 | 0.79558 (16) | 0.32932 (5) | 0.08322 (14) | 0.0220 (2) | |
C12 | 0.8997 (2) | 0.32246 (6) | −0.06228 (16) | 0.0306 (3) | |
H12 | 0.8182 | 0.3212 | −0.1702 | 0.037* | |
C13 | 1.0912 (2) | 0.31811 (7) | −0.0554 (2) | 0.0420 (3) | |
H13A | 1.1796 | 0.3192 | 0.0493 | 0.050* | |
H13B | 1.1405 | 0.3139 | −0.1552 | 0.050* | |
C14 | 0.54886 (18) | 0.38205 (6) | 0.52223 (15) | 0.0281 (3) | |
H14 | 0.6216 | 0.4153 | 0.5823 | 0.034* | |
C15 | 0.3968 (2) | 0.36033 (7) | 0.57897 (16) | 0.0339 (3) | |
H15A | 0.3203 | 0.3270 | 0.5225 | 0.041* | |
H15B | 0.3638 | 0.3780 | 0.6764 | 0.041* | |
O1 | 0.51761 (12) | 0.30019 (4) | 0.31854 (10) | 0.02288 (19) | |
H1A | 0.5584 | 0.2724 | 0.3898 | 0.034* | |
O2 | 0.67635 (13) | 0.27405 (4) | 0.07257 (10) | 0.0267 (2) | |
H2A | 0.6092 | 0.2750 | 0.1474 | 0.040* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0207 (5) | 0.0224 (5) | 0.0256 (5) | 0.0012 (4) | 0.0035 (4) | −0.0025 (4) |
C2 | 0.0228 (5) | 0.0253 (6) | 0.0332 (6) | −0.0043 (4) | 0.0069 (4) | −0.0040 (5) |
C3 | 0.0337 (6) | 0.0214 (5) | 0.0291 (6) | −0.0037 (4) | 0.0114 (5) | 0.0022 (4) |
C4 | 0.0400 (7) | 0.0204 (5) | 0.0381 (7) | −0.0016 (5) | 0.0115 (5) | 0.0027 (5) |
C5 | 0.0333 (6) | 0.0190 (5) | 0.0319 (6) | 0.0008 (4) | 0.0104 (5) | −0.0009 (4) |
C6 | 0.0278 (6) | 0.0240 (5) | 0.0268 (5) | −0.0054 (4) | 0.0040 (4) | −0.0055 (4) |
C7 | 0.0226 (5) | 0.0226 (5) | 0.0210 (5) | 0.0003 (4) | 0.0011 (4) | −0.0019 (4) |
C8 | 0.0226 (5) | 0.0190 (5) | 0.0207 (5) | −0.0006 (4) | 0.0040 (4) | −0.0001 (4) |
C9 | 0.0222 (5) | 0.0215 (5) | 0.0254 (5) | 0.0033 (4) | 0.0053 (4) | 0.0042 (4) |
C10 | 0.0258 (5) | 0.0229 (5) | 0.0215 (5) | −0.0003 (4) | 0.0046 (4) | 0.0039 (4) |
C11 | 0.0248 (5) | 0.0200 (5) | 0.0216 (5) | −0.0030 (4) | 0.0054 (4) | −0.0012 (4) |
C12 | 0.0399 (7) | 0.0279 (6) | 0.0267 (6) | −0.0051 (5) | 0.0135 (5) | −0.0039 (5) |
C13 | 0.0442 (8) | 0.0430 (8) | 0.0456 (8) | −0.0066 (6) | 0.0256 (6) | −0.0098 (6) |
C14 | 0.0329 (6) | 0.0271 (6) | 0.0249 (6) | 0.0026 (5) | 0.0075 (5) | −0.0014 (4) |
C15 | 0.0337 (6) | 0.0423 (7) | 0.0275 (6) | 0.0035 (5) | 0.0102 (5) | −0.0013 (5) |
O1 | 0.0263 (4) | 0.0213 (4) | 0.0204 (4) | −0.0038 (3) | 0.0034 (3) | 0.0019 (3) |
O2 | 0.0356 (5) | 0.0229 (4) | 0.0232 (4) | −0.0089 (3) | 0.0096 (3) | −0.0052 (3) |
C1—C11 | 1.5333 (15) | C8—O1 | 1.4322 (13) |
C1—C2 | 1.5626 (16) | C8—C14 | 1.5212 (15) |
C1—C7 | 1.5712 (16) | C8—C9 | 1.5481 (15) |
C1—H1 | 1.0000 | C9—C10 | 1.5944 (15) |
C2—C3 | 1.5565 (17) | C9—H9 | 1.0000 |
C2—C6 | 1.5614 (17) | C10—C11 | 1.5459 (15) |
C2—H2 | 1.0000 | C10—H10 | 1.0000 |
C3—C4 | 1.5237 (17) | C11—O2 | 1.4328 (13) |
C3—C10 | 1.5516 (16) | C11—C12 | 1.5173 (16) |
C3—H3 | 1.0000 | C12—C13 | 1.322 (2) |
C4—C5 | 1.5256 (17) | C12—H12 | 0.9500 |
C4—H4A | 0.9900 | C13—H13A | 0.9500 |
C4—H4B | 0.9900 | C13—H13B | 0.9500 |
C5—C6 | 1.5558 (17) | C14—C15 | 1.3177 (18) |
C5—C9 | 1.5585 (16) | C14—H14 | 0.9500 |
C5—H5 | 1.0000 | C15—H15A | 0.9500 |
C6—C7 | 1.5601 (16) | C15—H15B | 0.9500 |
C6—H6 | 1.0000 | O1—H1A | 0.8400 |
C7—C8 | 1.5396 (15) | O2—H2A | 0.8400 |
C7—H7 | 1.0000 | ||
C11—C1—C2 | 103.03 (9) | C6—C7—H7 | 115.0 |
C11—C1—C7 | 116.02 (9) | C1—C7—H7 | 115.0 |
C2—C1—C7 | 89.61 (8) | O1—C8—C14 | 108.29 (9) |
C11—C1—H1 | 114.9 | O1—C8—C7 | 115.95 (9) |
C2—C1—H1 | 114.9 | C14—C8—C7 | 109.35 (9) |
C7—C1—H1 | 114.9 | O1—C8—C9 | 112.47 (9) |
C3—C2—C6 | 102.97 (9) | C14—C8—C9 | 111.18 (9) |
C3—C2—C1 | 107.33 (9) | C7—C8—C9 | 99.41 (9) |
C6—C2—C1 | 90.30 (9) | C8—C9—C5 | 101.10 (9) |
C3—C2—H2 | 117.4 | C8—C9—C10 | 115.21 (9) |
C6—C2—H2 | 117.4 | C5—C9—C10 | 102.36 (9) |
C1—C2—H2 | 117.4 | C8—C9—H9 | 112.4 |
C4—C3—C10 | 105.27 (10) | C5—C9—H9 | 112.4 |
C4—C3—C2 | 103.39 (10) | C10—C9—H9 | 112.4 |
C10—C3—C2 | 100.03 (9) | C11—C10—C3 | 101.31 (9) |
C4—C3—H3 | 115.4 | C11—C10—C9 | 115.28 (9) |
C10—C3—H3 | 115.4 | C3—C10—C9 | 102.17 (9) |
C2—C3—H3 | 115.4 | C11—C10—H10 | 112.4 |
C3—C4—C5 | 95.39 (9) | C3—C10—H10 | 112.4 |
C3—C4—H4A | 112.7 | C9—C10—H10 | 112.4 |
C5—C4—H4A | 112.7 | O2—C11—C12 | 103.39 (9) |
C3—C4—H4B | 112.7 | O2—C11—C1 | 116.15 (9) |
C5—C4—H4B | 112.7 | C12—C11—C1 | 112.55 (10) |
H4A—C4—H4B | 110.2 | O2—C11—C10 | 114.93 (9) |
C4—C5—C6 | 103.59 (10) | C12—C11—C10 | 110.69 (9) |
C4—C5—C9 | 104.78 (10) | C1—C11—C10 | 99.46 (9) |
C6—C5—C9 | 99.86 (9) | C13—C12—C11 | 127.17 (12) |
C4—C5—H5 | 115.5 | C13—C12—H12 | 116.4 |
C6—C5—H5 | 115.5 | C11—C12—H12 | 116.4 |
C9—C5—H5 | 115.5 | C12—C13—H13A | 120.0 |
C5—C6—C7 | 107.76 (9) | C12—C13—H13B | 120.0 |
C5—C6—C2 | 102.78 (9) | H13A—C13—H13B | 120.0 |
C7—C6—C2 | 90.06 (8) | C15—C14—C8 | 125.17 (12) |
C5—C6—H6 | 117.4 | C15—C14—H14 | 117.4 |
C7—C6—H6 | 117.4 | C8—C14—H14 | 117.4 |
C2—C6—H6 | 117.4 | C14—C15—H15A | 120.0 |
C8—C7—C6 | 102.74 (9) | C14—C15—H15B | 120.0 |
C8—C7—C1 | 115.81 (9) | H15A—C15—H15B | 120.0 |
C6—C7—C1 | 90.03 (8) | C8—O1—H1A | 109.5 |
C8—C7—H7 | 115.0 | C11—O2—H2A | 109.5 |
C11—C1—C2—C3 | 12.86 (11) | C14—C8—C9—C5 | 60.93 (11) |
C7—C1—C2—C3 | −103.80 (9) | C7—C8—C9—C5 | −54.18 (10) |
C11—C1—C2—C6 | 116.56 (9) | O1—C8—C9—C10 | −67.96 (12) |
C7—C1—C2—C6 | −0.10 (8) | C14—C8—C9—C10 | 170.41 (9) |
C6—C2—C3—C4 | 33.62 (11) | C7—C8—C9—C10 | 55.30 (11) |
C1—C2—C3—C4 | 128.07 (10) | C4—C5—C9—C8 | 151.87 (9) |
C6—C2—C3—C10 | −74.86 (10) | C6—C5—C9—C8 | 44.86 (10) |
C1—C2—C3—C10 | 19.58 (11) | C4—C5—C9—C10 | 32.70 (11) |
C10—C3—C4—C5 | 51.65 (11) | C6—C5—C9—C10 | −74.31 (10) |
C2—C3—C4—C5 | −52.87 (11) | C4—C3—C10—C11 | −151.85 (9) |
C3—C4—C5—C6 | 52.79 (11) | C2—C3—C10—C11 | −44.86 (10) |
C3—C4—C5—C9 | −51.46 (11) | C4—C3—C10—C9 | −32.59 (11) |
C4—C5—C6—C7 | −127.37 (10) | C2—C3—C10—C9 | 74.39 (10) |
C9—C5—C6—C7 | −19.40 (11) | C8—C9—C10—C11 | 0.03 (13) |
C4—C5—C6—C2 | −33.14 (11) | C5—C9—C10—C11 | 108.76 (10) |
C9—C5—C6—C2 | 74.83 (10) | C8—C9—C10—C3 | −108.86 (10) |
C3—C2—C6—C5 | −0.27 (11) | C5—C9—C10—C3 | −0.14 (10) |
C1—C2—C6—C5 | −108.14 (9) | C2—C1—C11—O2 | −164.04 (9) |
C3—C2—C6—C7 | 107.97 (9) | C7—C1—C11—O2 | −68.00 (13) |
C1—C2—C6—C7 | 0.10 (8) | C2—C1—C11—C12 | 77.06 (11) |
C5—C6—C7—C8 | −13.17 (11) | C7—C1—C11—C12 | 173.10 (9) |
C2—C6—C7—C8 | −116.62 (9) | C2—C1—C11—C10 | −40.14 (10) |
C5—C6—C7—C1 | 103.35 (9) | C7—C1—C11—C10 | 55.90 (11) |
C2—C6—C7—C1 | −0.10 (8) | C3—C10—C11—O2 | 178.71 (9) |
C11—C1—C7—C8 | −0.04 (14) | C9—C10—C11—O2 | 69.30 (12) |
C2—C1—C7—C8 | 104.29 (10) | C3—C10—C11—C12 | −64.64 (11) |
C11—C1—C7—C6 | −104.24 (10) | C9—C10—C11—C12 | −174.05 (9) |
C2—C1—C7—C6 | 0.10 (8) | C3—C10—C11—C1 | 53.96 (10) |
C6—C7—C8—O1 | 161.29 (9) | C9—C10—C11—C1 | −55.45 (11) |
C1—C7—C8—O1 | 64.97 (12) | O2—C11—C12—C13 | −118.34 (14) |
C6—C7—C8—C14 | −75.97 (11) | C1—C11—C12—C13 | 7.78 (18) |
C1—C7—C8—C14 | −172.29 (9) | C10—C11—C12—C13 | 118.09 (15) |
C6—C7—C8—C9 | 40.53 (10) | O1—C8—C14—C15 | −12.52 (16) |
C1—C7—C8—C9 | −55.78 (11) | C7—C8—C14—C15 | −139.71 (13) |
O1—C8—C9—C5 | −177.44 (9) | C9—C8—C14—C15 | 111.52 (14) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2A···O1 | 0.84 | 1.73 | 2.5409 (12) | 160 |
O1—H1A···O2i | 0.84 | 1.85 | 2.6713 (11) | 167 |
Symmetry code: (i) x, −y+1/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C15H18O2 |
Mr | 230.29 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 173 |
a, b, c (Å) | 6.9355 (5), 21.3303 (13), 8.1859 (5) |
β (°) | 101.435 (3) |
V (Å3) | 1186.95 (13) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.48 × 0.40 × 0.34 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15589, 2869, 2525 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.661 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.115, 1.08 |
No. of reflections | 2869 |
No. of parameters | 156 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.35, −0.20 |
Computer programs: SMART-NT (Bruker, 1998), SAINT-Plus (Bruker, 1999), Mercury (Macrae et al., 2006) and WinGX (Farrugia, 1999), SHELXTL (Bruker, 1999) and PLATON (Spek, 2003).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2A···O1 | 0.84 | 1.73 | 2.5409 (12) | 160 |
O1—H1A···O2i | 0.84 | 1.85 | 2.6713 (11) | 167 |
Symmetry code: (i) x, −y+1/2, z+1/2. |
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The title compound (I) consists of a large apolar (lipophilic) hydrocarbon skeleton with polar dihydroxy units (Fig. 1). This unique compound is used as a starting molecule and derivatives thereof are coupled with desired peptides as potential HIV-1 protease inhibitors. A number of publications have focused on the molecular geometries of pentacycloundecane (PCU) cage derivatives (Flippen-Anderson et al., 1991; Linden et al., 2005; Kruger et al., 2005; Kruger et al., 2006). It has been reported that these compounds exhibit bond lengths deviating from the normal value of 1.54 Å. The shortening and elongation of specific C—C bonds in the cage molecule is also observed in (i) with the C—C bonds between C3—C4 & C4—C5 being the shortest (1.5237 (17) Å & 1.5256 (17) Å respectively) and the bonds between C1—C7 & C1—C2 being the longest (1.5712 (16) Å & 1.5626 (16) Å respectively). Interestingly the bonds between the cage and the alkene side chains (C11—C12 and C8—C14) are surprisingly shorter than expected value of C—C bonds (1.54 Å) with values of 1.5173 (16) Å and 1.5212 (15) Å respectively. The ethylene chains are in an energetically favorable conformation, with atoms C8, C11, C12, C13, C14 coplanar. Atoms C13 and C15 appear to be in a trans conformation with respect to each other. This allows the two hydroxyl groups to be in a favorable conformation for intra- and intermolecular hydrogen bonding.
In (I), the molecules pack in hydrogen-bonded bilayers. Both hydroxyl groups on the molecule participate in both intramolecular and intermolecular hydrogen bonding, each acting as a hydrogen bond donor and acceptor. Atom O2 interacts with atom O1 via H2A and atom O1 interacts with O2 of another cage molecule via H1A. Thus forming a hydrogen-bonded linear chain (Fig. 2). Because both the hydroxy groups of a molecule are involved in hydrogen bonding, molecules are connected in a linear fashion forming a sheet with alternating hydrogen bonding between the molecules. The linear sheets do not show any hydrogen bonding between the lipophilic parts of the bilayers but do show short contacts.