research communications
Structure of Equilenin at 100 K: an estrone-related steroid
aWolfson Centre for Materials Processing, Brunel University London, Kingston Lane, Uxbridge UB8 3PH, England, and bDepartment of Chemistry, University of Glasgow, Glasgow G12 8QQ, Scotland
*Correspondence e-mail: Chris.Frampton@Brunel.ac.uk
The structure of the estrone-related steroid, Equilenin, C18H18O2 (systematic name 3-hydroxy-13-methyl-11,12,13,14,15,16-hexahydrocyclopenta[a]phenanthren-17-one), has been determined at 100 K. The crystals are orthorhombic, P212121, and the of the molecule in the crystal has been determined by [Flack parameter = −0.05 (4)]. The C atoms of the A and B rings are almost coplanar, with an r.m.s. deviation from planarity of 0.0104 Å. The C ring has a sofa conformation, while the D ring has an with the methine C atom as the flap. The keto O atom and the methyl group are translated 0.78 and 0.79 Å, respectively, from the equivalent positions on 17β-estrone. In the crystal, molecules are linked by O—H⋯O hydrogen bonds, forming chains parallel to the c-axis direction.
Keywords: crystal structure; Equilenin; Equilin; estrone; steroid; conformation; hydrogen bonding.
CCDC reference: 1560649
1. Chemical context
The title compound, Equilenin 1, is one member of a series of three estrogenic the other members being Equilin 2 and 17β-estrone 3, that are components of the hormone replacement therapy medication, `Premarin', a mixture of natural estrogens isolated from the urine of pregnant equine mares. It can be seen from the scheme that on going from 17β-estrone 3 through to the title compound Equilenin 1, there is a progressive aromatization of the B ring of the steroid framework where in 1 rings A and B comprise a fully aromatic naphthalene core. The structure of Equilin 2, was determined by Sawicki et al. (1999b), who demonstrated that the presence of the unsaturated C7—C8 bond in the B ring rotates the C and D rings of the steroid such that the 17-keto oxygen atom, O17, is translated by 0.73 Å with respect to the analogous oxygen atom of 3 when an overlay of the two structures was performed based on the superposition of the A rings. The translation of the oxygen atom was implicated in the increased anti-human estrogenic 17β-hydroxysteroid dehydrogenase 1 (17β-HSD1) inhibitory behaviour of 2 with respect to 17β-estone 3 (Sawicki et al., 1999a). The impact of the inhibitory behaviour of 2 is that it causes a reduction of the active estrogen, 17β-estradiol, which is present in elevated concentrations in human breast tumour tissues and responsible for the accelerated growth of the tumour tissue. It is therefore of great interest to investigate what the structural and conformational consequences are on the C and D rings of the steroid framework of 1 by having fully unsaturated A and B rings. Although the unit-cell parameters of 1 at room temperature have been previously reported by Ohrt et al. (1967), no three-dimensional structure analysis of this important estrone steroid has been determined. Herein, we report on the of this final member of the estrone series of Equilenin 1, at 100 K.
2. Structural commentary
The 1, is orthorhombic, P212121 (Z '= 1) and its molecular structure is illustrated in Fig. 1. The data agree with the previously reported values (Ohrt et al., 1967) with the caveat that they are slightly smaller owing to some modest isotropic contraction due to the lower temperature. The atoms C1 through C10, which define the AB (napthalene) plane, are little affected by the chiral centres at C13 and C14, and are almost coplanar with an r.m.s. deviation of the fitted atoms of 0.0104 Å and a total puckering amplitude, Q, of 0.033 (2) Å. The greatest displacement from the ten-atom mean plane is atom C10 at −0.019 (1) Å. The C—C bond lengths of the AB rings follow the pattern in which C1—C2, C3—C4, C6—C7 and C8—C9 are significantly shorter, (mean value 1.372 Å), than the remaining seven bonds (mean value 1.421 Å) [Ahmed & Cruickshank, 1952; Cruickshank & Sparks, 1960], thus demonstrating that the AB ring system is a true aromatic naphthalene core. The aromatization of ring B does however, have a significant effect on the conformations of both the C and D rings of 1, compared to 2 and 3. In contrast to the regular chair conformation of the C rings of 2 and 3, the C ring of 1, has a highly symmetric 13β-envelope conformation characterized by a ΔCs(9) asymmetry parameter of 0.50° (Duax et al., 1976); and related pairs of torsion angles [C14—C8—C9—C11, C8—C9—C11—C12, −4.1 (2), 4.1 (2)°; C9—C11—C12—C13, C9—C8—C14—C13, −32.6 (2), 32.7 (2)°; C11—C12—C13—C14, C12—C13—C14—C8, 60.4 (2), −61.3 (1)°]. The downside impact of this conformational change in the C ring of 1 is such that in place of the asymmetric twist or half-chair D ring conformation demonstrated by 2 and 3, the D ring of Equilenin 1 displays a 14α-envelope conformation with a ΔCs(14) of 4.20°; the torsion angles for 1, (with related torsion angles for 2/3 are given in [/]) are C13—C14—C15—C16, C17—C13—C14—C15) −41.3 (2) [−40.2/-39.0]°, 43.3 (2) [44.5/42.9]°; C14—C13—C17—C16, C14—C15—C16—C17, −28.6 (2) [−31.0/-30.9]°, 23.0 (2) [19.6/19.4]°; and C15—C16—C17—C13, 3.6 (2) [8.1/7.5]°. Torsional angle data for 2 and 3 were extracted from structures GODTIC (Sawicki et al., 1999b) and ESTRON13 (Shikii et al., 2004), respectively (see Section 4, Database survey).
of EquileninCompounds 1 and 2, possibly owing to increased conformational constraint in the B ring, have lower oestrongenic activity than 17β-estrone itself, which has the B ring as the principal point of molecular flexibility (Duax et al., 1976; Busetta et al., 1973). Interestingly this reduction in activity (Marshall, 1970) does not directly relate to the crystallographically determined degree to which the A and B rings of the steroid are constrained to coplanarity, since 1, possessing an essentially planar naphthalene core, is about five times more estrogenic than 2 which features only approximate coplanarity of its A and B rings with an r.m.s. deviation of the fitted atoms of 0.102 Å, and a total puckering amplitude of 0.270 (2) Å (Sawicki et al., 1999b). An overlay of structures 1 (red), 2 (blue) and 3 (green) is shown in Fig. 2. The overlay was performed by a superposition of the atoms in the A ring only. From this overlay it can be calculated that the keto oxygen atom is translated by 0.78 and 0.69 Å, respectively, for compounds 1 and 2 from its position on 3. Perhaps more significant is the degree of translation of the methyl group C18 which is translated by 0.79 and 1.40 Å, respectively, for compounds 1 and 2 from its position on 3 which may account for the increased estrogenic activity of 1 over 2. The stereochemistry assignments at C13 and C14 are S, S; confirmed by through the Flack x parameter value of −0.05 (4).
3. Supramolecular features
In the crystal, the Equilenin 1 molecules are linked head-to-tail by a single O—H⋯Oi hydrogen bond (Table 1), to form chains propagating along the c-axis direction. A view along the b-axis of the crystal packing of the title compound is shown in Fig. 3.
4. Database survey
A search of the Cambridge Structural Database (CSD, Version 5.38, last update February 2017; Groom et al., 2016) for the basic steroid ABCD ring framework yielded 401 hits although the hits for 1 and 2 could only be accessed by introducing the aromaticity into the B ring. Of the 401 hits there were eight hits for the structure of 17β-estrone, 3 (ESTRON03–05 and ESTRON10–15), which exists in three polymorphic forms. They include, form I, orthorhombic P212121 (ESTRON11: Busetta et al., 1973), form II, orthorhombic P212121 (ESTRON03: Debaerdemaeker, 1972; ESTRON04: van den Bossche et al., 1971; ESTRON10: Busetta et al., 1973; ESTRON13: Shikii et al., 2004; ESTRON14: Zhurova et al., 2006) and form III, monoclinic P21 (Z′ = 2) (ESTRON05, unit-cell determination only: Ohrt et al., 1964; ESTRON12: Busetta et al., 1973). The polymorphic behaviour appears to be attributable to the crystal packing and has no significant influence on the conformation of the steroid framework. There was a single entry for 2 (GODTIC: Sawicki et al., 1999b) and a single entry for 1 (QQQAMM, unit-cell determination only: Ohrt et al., 1967).
5. Synthesis and crystallization
In common with Equilin 2 the title compound, 1, was isolated from the urine of a pregnant mare (Girard et al., 1932; Fieser & Fieser, 1959). The sample used for the X-ray data collection was gifted to us from the J. W. Cook collection of the University of Glasgow. Suitable crystals were obtained as needles from ethanol solution, m.p. 531–532 K (evacuated sealed capillary).
6. Refinement
Crystal data, data collection and structure . The O-bound H atom was located from a difference-Fourier map and freely refined. All remaining H atoms were placed geometrically in idealized positions and refined using a riding model (including about the methyl C—C bond): C—H = 0.95–0.99 Å with Uiso(H) = 1.5Ueq(C-methyl) and 1.2Ueq(C) for other H atoms. The absolute stereochemistry of 1, was confirmed through the Flack x parameter value of −0.05 (4). This was determined using 1130 quotients [(I+)−(I−)]/[(I+)+(I−)] (Parsons et al., 2013).
details are summarized in Table 2Supporting information
CCDC reference: 1560649
https://doi.org/10.1107/S2056989017010532/su5383sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989017010532/su5383Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2056989017010532/su5383Isup3.cml
Data collection: CrysAlis PRO (Rigaku Oxford Diffraction, 2015); cell
CrysAlis PRO (Rigaku Oxford Diffraction, 2015); data reduction: CrysAlis PRO (Rigaku Oxford Diffraction, 2015); program(s) used to solve structure: SHELXD2014 (Sheldrick, 2010); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and publCIF (Westrip, 2010).C18H18O2 | Dx = 1.300 Mg m−3 |
Mr = 266.32 | Melting point: 531 K |
Orthorhombic, P212121 | Cu Kα radiation, λ = 1.54184 Å |
a = 7.27709 (7) Å | Cell parameters from 13177 reflections |
b = 7.32686 (6) Å | θ = 3.5–76.4° |
c = 25.5179 (2) Å | µ = 0.66 mm−1 |
V = 1360.57 (2) Å3 | T = 100 K |
Z = 4 | Rod, colourless |
F(000) = 568 | 0.41 × 0.12 × 0.07 mm |
Rigaku Oxford Diffraction SuperNova Dualflex AtlasS2 diffractometer | 2769 independent reflections |
Radiation source: fine-focus sealed X-ray tube, Enhance (Cu) X-ray Source | 2754 reflections with I > 2σ(I) |
Detector resolution: 5.2921 pixels mm-1 | Rint = 0.022 |
ω scans | θmax = 74.5°, θmin = 3.5° |
Absorption correction: multi-scan (CrysAlis PRO; Rigaku Oxford Diffraction, 2015) | h = −9→7 |
Tmin = 0.853, Tmax = 0.960 | k = −9→9 |
16660 measured reflections | l = −31→31 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.029 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.080 | w = 1/[σ2(Fo2) + (0.0525P)2 + 0.310P] where P = (Fo2 + 2Fc2)/3 |
S = 1.01 | (Δ/σ)max < 0.001 |
2769 reflections | Δρmax = 0.26 e Å−3 |
186 parameters | Δρmin = −0.17 e Å−3 |
0 restraints | Absolute structure: Flack x determined using 1130 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013) |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.05 (4) |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
O3 | 0.06030 (17) | 0.42177 (17) | 0.09478 (4) | 0.0234 (3) | |
H3A | 0.155 (4) | 0.472 (4) | 0.0738 (10) | 0.058 (8)* | |
O17 | 0.23720 (17) | 0.44067 (19) | 0.51461 (4) | 0.0277 (3) | |
C1 | −0.0140 (2) | 0.4004 (2) | 0.23492 (6) | 0.0184 (3) | |
H1A | −0.1120 | 0.3698 | 0.2579 | 0.022* | |
C2 | −0.0417 (2) | 0.3930 (2) | 0.18189 (6) | 0.0191 (3) | |
H2A | −0.1585 | 0.3588 | 0.1685 | 0.023* | |
C3 | 0.1025 (2) | 0.4357 (2) | 0.14700 (6) | 0.0184 (3) | |
C4 | 0.2710 (2) | 0.4870 (2) | 0.16578 (6) | 0.0185 (3) | |
H4A | 0.3673 | 0.5152 | 0.1420 | 0.022* | |
C5 | 0.3030 (2) | 0.4983 (2) | 0.22075 (6) | 0.0164 (3) | |
C6 | 0.4744 (2) | 0.5542 (2) | 0.24123 (6) | 0.0191 (3) | |
H6A | 0.5719 | 0.5844 | 0.2181 | 0.023* | |
C7 | 0.5009 (2) | 0.5651 (2) | 0.29424 (6) | 0.0182 (3) | |
H7A | 0.6172 | 0.6022 | 0.3073 | 0.022* | |
C8 | 0.3584 (2) | 0.5223 (2) | 0.32991 (6) | 0.0162 (3) | |
C9 | 0.1889 (2) | 0.4662 (2) | 0.31167 (6) | 0.0156 (3) | |
C10 | 0.1585 (2) | 0.4530 (2) | 0.25640 (6) | 0.0156 (3) | |
C11 | 0.0307 (2) | 0.4177 (2) | 0.34819 (6) | 0.0181 (3) | |
H11A | −0.0010 | 0.2877 | 0.3427 | 0.022* | |
H11B | −0.0777 | 0.4910 | 0.3379 | 0.022* | |
C12 | 0.0654 (2) | 0.4477 (2) | 0.40723 (6) | 0.0188 (3) | |
H12A | 0.0321 | 0.5743 | 0.4169 | 0.023* | |
H12B | −0.0125 | 0.3634 | 0.4279 | 0.023* | |
C13 | 0.2666 (2) | 0.4136 (2) | 0.41985 (5) | 0.0174 (3) | |
C14 | 0.3840 (2) | 0.5486 (2) | 0.38816 (6) | 0.0175 (3) | |
H14A | 0.3364 | 0.6733 | 0.3965 | 0.021* | |
C15 | 0.5749 (2) | 0.5349 (3) | 0.41347 (6) | 0.0233 (3) | |
H15A | 0.6510 | 0.6432 | 0.4053 | 0.028* | |
H15B | 0.6404 | 0.4234 | 0.4020 | 0.028* | |
C16 | 0.5263 (2) | 0.5265 (3) | 0.47245 (6) | 0.0278 (4) | |
H16A | 0.6101 | 0.4423 | 0.4911 | 0.033* | |
H16B | 0.5360 | 0.6491 | 0.4886 | 0.033* | |
C17 | 0.3293 (2) | 0.4572 (2) | 0.47493 (6) | 0.0210 (3) | |
C18 | 0.3214 (2) | 0.2130 (2) | 0.41011 (6) | 0.0209 (3) | |
H18A | 0.2300 | 0.1321 | 0.4261 | 0.031* | |
H18B | 0.4422 | 0.1896 | 0.4257 | 0.031* | |
H18C | 0.3269 | 0.1899 | 0.3723 | 0.031* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O3 | 0.0254 (6) | 0.0327 (6) | 0.0121 (5) | −0.0031 (5) | −0.0025 (4) | 0.0006 (4) |
O17 | 0.0239 (6) | 0.0460 (7) | 0.0131 (5) | −0.0037 (6) | 0.0025 (4) | −0.0009 (5) |
C1 | 0.0173 (7) | 0.0209 (7) | 0.0170 (7) | −0.0030 (6) | 0.0015 (6) | 0.0020 (5) |
C2 | 0.0163 (7) | 0.0216 (7) | 0.0193 (7) | −0.0032 (6) | −0.0028 (6) | 0.0011 (6) |
C3 | 0.0219 (7) | 0.0202 (7) | 0.0132 (7) | 0.0004 (6) | −0.0015 (6) | 0.0014 (6) |
C4 | 0.0191 (7) | 0.0218 (7) | 0.0146 (7) | 0.0019 (6) | 0.0025 (6) | 0.0023 (5) |
C5 | 0.0160 (7) | 0.0183 (7) | 0.0149 (7) | 0.0011 (6) | 0.0011 (5) | 0.0020 (5) |
C6 | 0.0146 (7) | 0.0254 (8) | 0.0171 (7) | 0.0000 (6) | 0.0037 (6) | 0.0035 (6) |
C7 | 0.0122 (7) | 0.0243 (8) | 0.0182 (7) | −0.0020 (6) | −0.0012 (6) | 0.0030 (6) |
C8 | 0.0157 (7) | 0.0192 (7) | 0.0136 (7) | 0.0012 (6) | 0.0005 (5) | 0.0017 (6) |
C9 | 0.0145 (7) | 0.0183 (7) | 0.0141 (6) | 0.0004 (6) | 0.0020 (5) | 0.0019 (5) |
C10 | 0.0153 (7) | 0.0163 (7) | 0.0152 (7) | 0.0014 (6) | 0.0012 (5) | 0.0014 (5) |
C11 | 0.0132 (7) | 0.0269 (8) | 0.0142 (7) | −0.0015 (6) | 0.0011 (5) | 0.0009 (6) |
C12 | 0.0132 (7) | 0.0291 (8) | 0.0143 (6) | 0.0007 (6) | 0.0021 (5) | 0.0000 (6) |
C13 | 0.0146 (7) | 0.0256 (7) | 0.0121 (6) | 0.0002 (6) | 0.0006 (5) | 0.0010 (6) |
C14 | 0.0145 (7) | 0.0241 (7) | 0.0140 (7) | −0.0019 (6) | −0.0004 (5) | 0.0004 (6) |
C15 | 0.0154 (7) | 0.0393 (9) | 0.0153 (7) | −0.0042 (7) | −0.0021 (5) | 0.0029 (7) |
C16 | 0.0200 (8) | 0.0483 (10) | 0.0151 (7) | −0.0047 (8) | −0.0027 (6) | 0.0019 (7) |
C17 | 0.0193 (7) | 0.0287 (8) | 0.0148 (7) | 0.0018 (7) | −0.0010 (5) | 0.0011 (6) |
C18 | 0.0195 (7) | 0.0261 (8) | 0.0170 (7) | 0.0013 (6) | 0.0010 (6) | 0.0030 (6) |
O3—C3 | 1.3714 (17) | C11—C12 | 1.5433 (19) |
O3—H3A | 0.95 (3) | C11—H11A | 0.9900 |
O17—C17 | 1.220 (2) | C11—H11B | 0.9900 |
C1—C2 | 1.369 (2) | C12—C13 | 1.520 (2) |
C1—C10 | 1.423 (2) | C12—H12A | 0.9900 |
C1—H1A | 0.9500 | C12—H12B | 0.9900 |
C2—C3 | 1.411 (2) | C13—C17 | 1.5118 (19) |
C2—H2A | 0.9500 | C13—C14 | 1.537 (2) |
C3—C4 | 1.369 (2) | C13—C18 | 1.544 (2) |
C4—C5 | 1.4243 (19) | C14—C15 | 1.535 (2) |
C4—H4A | 0.9500 | C14—H14A | 1.0000 |
C5—C6 | 1.413 (2) | C15—C16 | 1.547 (2) |
C5—C10 | 1.429 (2) | C15—H15A | 0.9900 |
C6—C7 | 1.369 (2) | C15—H15B | 0.9900 |
C6—H6A | 0.9500 | C16—C17 | 1.523 (2) |
C7—C8 | 1.414 (2) | C16—H16A | 0.9900 |
C7—H7A | 0.9500 | C16—H16B | 0.9900 |
C8—C9 | 1.381 (2) | C18—H18A | 0.9800 |
C8—C14 | 1.5103 (19) | C18—H18B | 0.9800 |
C9—C10 | 1.4309 (19) | C18—H18C | 0.9800 |
C9—C11 | 1.5234 (19) | ||
C3—O3—H3A | 111.0 (17) | C13—C12—H12A | 109.7 |
C2—C1—C10 | 121.43 (14) | C11—C12—H12A | 109.7 |
C2—C1—H1A | 119.3 | C13—C12—H12B | 109.7 |
C10—C1—H1A | 119.3 | C11—C12—H12B | 109.7 |
C1—C2—C3 | 120.34 (14) | H12A—C12—H12B | 108.2 |
C1—C2—H2A | 119.8 | C17—C13—C12 | 116.95 (12) |
C3—C2—H2A | 119.8 | C17—C13—C14 | 100.69 (12) |
C4—C3—O3 | 124.14 (14) | C12—C13—C14 | 108.58 (12) |
C4—C3—C2 | 120.39 (13) | C17—C13—C18 | 105.82 (13) |
O3—C3—C2 | 115.46 (14) | C12—C13—C18 | 111.80 (13) |
C3—C4—C5 | 120.47 (14) | C14—C13—C18 | 112.60 (12) |
C3—C4—H4A | 119.8 | C8—C14—C15 | 121.14 (13) |
C5—C4—H4A | 119.8 | C8—C14—C13 | 111.54 (13) |
C6—C5—C4 | 121.68 (14) | C15—C14—C13 | 103.87 (12) |
C6—C5—C10 | 118.77 (13) | C8—C14—H14A | 106.5 |
C4—C5—C10 | 119.55 (14) | C15—C14—H14A | 106.5 |
C7—C6—C5 | 120.43 (14) | C13—C14—H14A | 106.5 |
C7—C6—H6A | 119.8 | C14—C15—C16 | 101.83 (12) |
C5—C6—H6A | 119.8 | C14—C15—H15A | 111.4 |
C6—C7—C8 | 121.33 (14) | C16—C15—H15A | 111.4 |
C6—C7—H7A | 119.3 | C14—C15—H15B | 111.4 |
C8—C7—H7A | 119.3 | C16—C15—H15B | 111.4 |
C9—C8—C7 | 120.24 (13) | H15A—C15—H15B | 109.3 |
C9—C8—C14 | 118.66 (13) | C17—C16—C15 | 105.59 (13) |
C7—C8—C14 | 120.98 (14) | C17—C16—H16A | 110.6 |
C8—C9—C10 | 119.37 (13) | C15—C16—H16A | 110.6 |
C8—C9—C11 | 122.58 (13) | C17—C16—H16B | 110.6 |
C10—C9—C11 | 118.06 (13) | C15—C16—H16B | 110.6 |
C1—C10—C5 | 117.81 (13) | H16A—C16—H16B | 108.8 |
C1—C10—C9 | 122.30 (13) | O17—C17—C13 | 125.78 (15) |
C5—C10—C9 | 119.86 (14) | O17—C17—C16 | 125.78 (15) |
C9—C11—C12 | 116.13 (13) | C13—C17—C16 | 108.43 (13) |
C9—C11—H11A | 108.3 | C13—C18—H18A | 109.5 |
C12—C11—H11A | 108.3 | C13—C18—H18B | 109.5 |
C9—C11—H11B | 108.3 | H18A—C18—H18B | 109.5 |
C12—C11—H11B | 108.3 | C13—C18—H18C | 109.5 |
H11A—C11—H11B | 107.4 | H18A—C18—H18C | 109.5 |
C13—C12—C11 | 109.95 (12) | H18B—C18—H18C | 109.5 |
C10—C1—C2—C3 | 0.7 (2) | C10—C9—C11—C12 | −175.62 (14) |
C1—C2—C3—C4 | −0.7 (2) | C9—C11—C12—C13 | −32.63 (19) |
C1—C2—C3—O3 | 179.27 (14) | C11—C12—C13—C17 | 173.40 (14) |
O3—C3—C4—C5 | 179.87 (14) | C11—C12—C13—C14 | 60.42 (17) |
C2—C3—C4—C5 | −0.2 (2) | C11—C12—C13—C18 | −64.41 (16) |
C3—C4—C5—C6 | −178.75 (15) | C9—C8—C14—C15 | 155.31 (15) |
C3—C4—C5—C10 | 1.0 (2) | C7—C8—C14—C15 | −28.7 (2) |
C4—C5—C6—C7 | 179.52 (14) | C9—C8—C14—C13 | 32.65 (19) |
C10—C5—C6—C7 | −0.2 (2) | C7—C8—C14—C13 | −151.31 (14) |
C5—C6—C7—C8 | −0.4 (2) | C17—C13—C14—C8 | 175.33 (13) |
C6—C7—C8—C9 | 0.7 (2) | C12—C13—C14—C8 | −61.31 (16) |
C6—C7—C8—C14 | −175.24 (15) | C18—C13—C14—C8 | 63.05 (16) |
C7—C8—C9—C10 | −0.4 (2) | C17—C13—C14—C15 | 43.25 (15) |
C14—C8—C9—C10 | 175.63 (14) | C12—C13—C14—C15 | 166.61 (13) |
C7—C8—C9—C11 | 179.82 (14) | C18—C13—C14—C15 | −69.03 (16) |
C14—C8—C9—C11 | −4.1 (2) | C8—C14—C15—C16 | −167.57 (14) |
C2—C1—C10—C5 | 0.1 (2) | C13—C14—C15—C16 | −41.33 (17) |
C2—C1—C10—C9 | 178.36 (15) | C14—C15—C16—C17 | 22.97 (18) |
C6—C5—C10—C1 | 178.82 (14) | C12—C13—C17—O17 | 33.7 (3) |
C4—C5—C10—C1 | −0.9 (2) | C14—C13—C17—O17 | 151.02 (18) |
C6—C5—C10—C9 | 0.5 (2) | C18—C13—C17—O17 | −91.6 (2) |
C4—C5—C10—C9 | −179.25 (14) | C12—C13—C17—C16 | −145.92 (15) |
C8—C9—C10—C1 | −178.42 (14) | C14—C13—C17—C16 | −28.56 (16) |
C11—C9—C10—C1 | 1.3 (2) | C18—C13—C17—C16 | 88.83 (16) |
C8—C9—C10—C5 | −0.2 (2) | C15—C16—C17—O17 | −175.96 (18) |
C11—C9—C10—C5 | 179.60 (13) | C15—C16—C17—C13 | 3.62 (19) |
C8—C9—C11—C12 | 4.1 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3A···O17i | 0.95 (3) | 1.82 (3) | 2.7153 (17) | 157 (3) |
Symmetry code: (i) −x+1/2, −y+1, z−1/2. |
Acknowledgements
We thank the University of Glasgow for the gift of the sample from the J. W. Cook collection.
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