organic compounds
4-[4-(Piperidin-1-yl)piperidin-1-yl]benzonitrile
aState Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
*Correspondence e-mail: luo_youfu@scu.edu.cn
In the title compound, C17H23N3, both piperidine rings adopt chair conformations. In the crystal packing, intermolecular C—H⋯N hydrogen bonds and C—H⋯π interactions are present.
Experimental
Crystal data
|
Refinement
|
Data collection: CrystalClear (Rigaku/MSC, 2005); cell CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ChemBioDraw Ultra CambridgeSoft (2008); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S160053680905507X/kp2240sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053680905507X/kp2240Isup2.hkl
A DMSO solution of 1-(piperidin-4-yl)piperidine (4.37 g, 0.01 mol) with 4-fluorobenzonitrile (1.21 g, 0.01 mol) was heated to reflux for 3 h, then water (50 ml) was added into the solution. The mixture was extracted with CH2Cl2. After the solvent was removed a red crystalline powder was obtained; its recrystallisation from a methanol solution after 5 days yielded single crystals.
4-(4-(Piperidin-1-yl)piperidin-1-yl)benzonitrile are key intermediates which can be used to synthesize 3-aminopyrazole derivatives, which can be used as precursors for anticancer and anti-malarial agents. In the structure of the title molecule (Fig. 1) both piperidine rings are in a chair conformation. A crystal packing is dominated by van der Waals interactions (Fig. 2).
For general background, see: Pevarello et al. (2006).
Data collection: CrystalClear (Rigaku/MSC, 2005); cell
CrystalClear (Rigaku/MSC, 2005); data reduction: CrystalClear (Rigaku/MSC, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ChemBioDraw Ultra (CambridgeSoft, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).Fig. 1. The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level. | |
Fig. 2. The crystal packing of I dominated by van der Waals interactions. |
C17H23N3 | F(000) = 584 |
Mr = 269.38 | Dx = 1.209 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 4488 reflections |
a = 10.090 (2) Å | θ = 2.7–27.9° |
b = 11.100 (2) Å | µ = 0.07 mm−1 |
c = 13.446 (3) Å | T = 113 K |
β = 100.72 (3)° | Block, red |
V = 1479.7 (5) Å3 | 0.26 × 0.25 × 0.20 mm |
Z = 4 |
Rigaku Saturn CCD area-detector diffractometer | 3500 independent reflections |
Radiation source: rotating anode | 2749 reflections with I > 2σ(I) |
Confocal monochromator | Rint = 0.032 |
Detector resolution: 7.31 pixels mm-1 | θmax = 27.9°, θmin = 2.8° |
ω and φ scans | h = −13→10 |
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005) | k = −14→14 |
Tmin = 0.981, Tmax = 0.986 | l = −17→17 |
11970 measured reflections |
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)] = 0.038 | H-atom parameters constrained |
wR(F2) = 0.111 | w = 1/[σ2(Fo2) + (0.0612P)2 + 0.0668P] where P = (Fo2 + 2Fc2)/3 |
S = 1.12 | (Δ/σ)max < 0.001 |
3500 reflections | Δρmax = 0.27 e Å−3 |
182 parameters | Δρmin = −0.19 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.033 (7) |
C17H23N3 | V = 1479.7 (5) Å3 |
Mr = 269.38 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 10.090 (2) Å | µ = 0.07 mm−1 |
b = 11.100 (2) Å | T = 113 K |
c = 13.446 (3) Å | 0.26 × 0.25 × 0.20 mm |
β = 100.72 (3)° |
Rigaku Saturn CCD area-detector diffractometer | 3500 independent reflections |
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005) | 2749 reflections with I > 2σ(I) |
Tmin = 0.981, Tmax = 0.986 | Rint = 0.032 |
11970 measured reflections |
R[F2 > 2σ(F2)] = 0.038 | 0 restraints |
wR(F2) = 0.111 | H-atom parameters constrained |
S = 1.12 | Δρmax = 0.27 e Å−3 |
3500 reflections | Δρmin = −0.19 e Å−3 |
182 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 | ||
N1 | 0.19321 (8) | 0.59022 (8) | 0.73578 (6) | 0.0193 (2) | |
N2 | 0.26675 (8) | 0.49828 (7) | 0.43659 (6) | 0.0187 (2) | |
N3 | 0.48688 (9) | 0.35177 (8) | 0.00345 (7) | 0.0256 (2) | |
C1 | 0.21163 (10) | 0.49931 (10) | 0.81631 (8) | 0.0225 (2) | |
H1A | 0.3069 | 0.4727 | 0.8304 | 0.027* | |
H1B | 0.1547 | 0.4283 | 0.7934 | 0.027* | |
C2 | 0.17411 (11) | 0.54896 (10) | 0.91273 (8) | 0.0270 (3) | |
H2A | 0.2363 | 0.6154 | 0.9391 | 0.032* | |
H2B | 0.1839 | 0.4848 | 0.9647 | 0.032* | |
C3 | 0.02945 (11) | 0.59541 (11) | 0.89283 (9) | 0.0310 (3) | |
H3A | −0.0339 | 0.5270 | 0.8768 | 0.037* | |
H3B | 0.0102 | 0.6360 | 0.9542 | 0.037* | |
C4 | 0.00956 (11) | 0.68349 (11) | 0.80492 (9) | 0.0307 (3) | |
H4A | 0.0638 | 0.7569 | 0.8249 | 0.037* | |
H4B | −0.0865 | 0.7074 | 0.7881 | 0.037* | |
C5 | 0.05156 (10) | 0.62790 (11) | 0.71205 (8) | 0.0274 (3) | |
H5A | −0.0062 | 0.5573 | 0.6894 | 0.033* | |
H5B | 0.0392 | 0.6875 | 0.6563 | 0.033* | |
C6 | 0.24849 (10) | 0.54949 (9) | 0.64737 (8) | 0.0182 (2) | |
H6 | 0.3448 | 0.5272 | 0.6733 | 0.022* | |
C7 | 0.18209 (10) | 0.43925 (9) | 0.59102 (8) | 0.0205 (2) | |
H7A | 0.1816 | 0.3721 | 0.6394 | 0.025* | |
H7B | 0.0873 | 0.4584 | 0.5608 | 0.025* | |
C8 | 0.25693 (10) | 0.40038 (9) | 0.50799 (8) | 0.0204 (2) | |
H8A | 0.3488 | 0.3734 | 0.5391 | 0.024* | |
H8B | 0.2093 | 0.3313 | 0.4708 | 0.024* | |
C9 | 0.32454 (11) | 0.60897 (9) | 0.48736 (8) | 0.0224 (2) | |
H9A | 0.3206 | 0.6742 | 0.4366 | 0.027* | |
H9B | 0.4206 | 0.5948 | 0.5172 | 0.027* | |
C10 | 0.25036 (11) | 0.64891 (9) | 0.56997 (8) | 0.0229 (2) | |
H10A | 0.1566 | 0.6711 | 0.5394 | 0.027* | |
H10B | 0.2951 | 0.7211 | 0.6042 | 0.027* | |
C11 | 0.31345 (9) | 0.46754 (9) | 0.34801 (7) | 0.0179 (2) | |
C12 | 0.32252 (10) | 0.55520 (9) | 0.27405 (8) | 0.0209 (2) | |
H12 | 0.2976 | 0.6360 | 0.2849 | 0.025* | |
C13 | 0.36689 (10) | 0.52613 (9) | 0.18606 (8) | 0.0212 (2) | |
H13 | 0.3727 | 0.5870 | 0.1374 | 0.025* | |
C14 | 0.40341 (10) | 0.40774 (9) | 0.16801 (8) | 0.0182 (2) | |
C15 | 0.39452 (10) | 0.31974 (9) | 0.24037 (8) | 0.0203 (2) | |
H15 | 0.4191 | 0.2390 | 0.2289 | 0.024* | |
C16 | 0.35023 (10) | 0.34886 (9) | 0.32857 (8) | 0.0205 (2) | |
H16 | 0.3445 | 0.2876 | 0.3770 | 0.025* | |
C17 | 0.45003 (10) | 0.37726 (9) | 0.07679 (8) | 0.0200 (2) |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0189 (4) | 0.0234 (5) | 0.0162 (4) | 0.0020 (3) | 0.0049 (3) | −0.0006 (3) |
N2 | 0.0253 (4) | 0.0146 (4) | 0.0169 (4) | −0.0026 (3) | 0.0060 (3) | −0.0002 (3) |
N3 | 0.0337 (5) | 0.0195 (5) | 0.0252 (5) | −0.0013 (4) | 0.0101 (4) | −0.0025 (4) |
C1 | 0.0240 (5) | 0.0248 (5) | 0.0194 (5) | 0.0000 (4) | 0.0053 (4) | 0.0015 (4) |
C2 | 0.0287 (6) | 0.0343 (6) | 0.0190 (6) | −0.0034 (5) | 0.0071 (4) | −0.0014 (5) |
C3 | 0.0272 (6) | 0.0414 (7) | 0.0273 (6) | −0.0046 (5) | 0.0127 (5) | −0.0073 (5) |
C4 | 0.0237 (5) | 0.0400 (7) | 0.0300 (6) | 0.0065 (5) | 0.0085 (5) | −0.0051 (5) |
C5 | 0.0215 (5) | 0.0370 (6) | 0.0237 (6) | 0.0071 (5) | 0.0044 (4) | −0.0020 (5) |
C6 | 0.0183 (5) | 0.0197 (5) | 0.0170 (5) | 0.0005 (4) | 0.0045 (4) | −0.0008 (4) |
C7 | 0.0226 (5) | 0.0200 (5) | 0.0196 (5) | −0.0024 (4) | 0.0058 (4) | 0.0011 (4) |
C8 | 0.0272 (5) | 0.0160 (5) | 0.0189 (5) | −0.0022 (4) | 0.0069 (4) | 0.0008 (4) |
C9 | 0.0287 (5) | 0.0187 (5) | 0.0210 (5) | −0.0062 (4) | 0.0076 (4) | −0.0031 (4) |
C10 | 0.0315 (6) | 0.0177 (5) | 0.0212 (6) | −0.0024 (4) | 0.0094 (4) | −0.0023 (4) |
C11 | 0.0178 (5) | 0.0183 (5) | 0.0170 (5) | −0.0011 (4) | 0.0018 (4) | −0.0009 (4) |
C12 | 0.0263 (5) | 0.0161 (5) | 0.0209 (5) | 0.0028 (4) | 0.0059 (4) | 0.0000 (4) |
C13 | 0.0268 (5) | 0.0187 (5) | 0.0185 (5) | 0.0012 (4) | 0.0054 (4) | 0.0027 (4) |
C14 | 0.0196 (5) | 0.0181 (5) | 0.0171 (5) | −0.0009 (4) | 0.0033 (4) | −0.0014 (4) |
C15 | 0.0238 (5) | 0.0164 (5) | 0.0205 (6) | 0.0007 (4) | 0.0033 (4) | −0.0017 (4) |
C16 | 0.0253 (5) | 0.0170 (5) | 0.0187 (5) | −0.0007 (4) | 0.0031 (4) | 0.0011 (4) |
C17 | 0.0236 (5) | 0.0145 (5) | 0.0216 (6) | −0.0012 (4) | 0.0038 (4) | 0.0000 (4) |
N1—C5 | 1.4663 (13) | C6—H6 | 1.0000 |
N1—C1 | 1.4664 (13) | C7—C8 | 1.5219 (14) |
N1—C6 | 1.4749 (13) | C7—H7A | 0.9900 |
N2—C11 | 1.4020 (13) | C7—H7B | 0.9900 |
N2—C8 | 1.4656 (13) | C8—H8A | 0.9900 |
N2—C9 | 1.4723 (13) | C8—H8B | 0.9900 |
N3—C17 | 1.1520 (13) | C9—C10 | 1.5164 (14) |
C1—C2 | 1.5200 (14) | C9—H9A | 0.9900 |
C1—H1A | 0.9900 | C9—H9B | 0.9900 |
C1—H1B | 0.9900 | C10—H10A | 0.9900 |
C2—C3 | 1.5241 (16) | C10—H10B | 0.9900 |
C2—H2A | 0.9900 | C11—C16 | 1.4063 (14) |
C2—H2B | 0.9900 | C11—C12 | 1.4064 (14) |
C3—C4 | 1.5183 (17) | C12—C13 | 1.3788 (14) |
C3—H3A | 0.9900 | C12—H12 | 0.9500 |
C3—H3B | 0.9900 | C13—C14 | 1.3981 (14) |
C4—C5 | 1.5220 (15) | C13—H13 | 0.9500 |
C4—H4A | 0.9900 | C14—C15 | 1.3933 (14) |
C4—H4B | 0.9900 | C14—C17 | 1.4335 (14) |
C5—H5A | 0.9900 | C15—C16 | 1.3811 (14) |
C5—H5B | 0.9900 | C15—H15 | 0.9500 |
C6—C10 | 1.5195 (14) | C16—H16 | 0.9500 |
C6—C7 | 1.5269 (14) | ||
C5—N1—C1 | 109.98 (8) | C8—C7—H7A | 109.4 |
C5—N1—C6 | 114.29 (8) | C6—C7—H7A | 109.4 |
C1—N1—C6 | 111.67 (8) | C8—C7—H7B | 109.4 |
C11—N2—C8 | 116.77 (8) | C6—C7—H7B | 109.4 |
C11—N2—C9 | 115.49 (8) | H7A—C7—H7B | 108.0 |
C8—N2—C9 | 112.59 (8) | N2—C8—C7 | 111.93 (8) |
N1—C1—C2 | 111.27 (9) | N2—C8—H8A | 109.2 |
N1—C1—H1A | 109.4 | C7—C8—H8A | 109.2 |
C2—C1—H1A | 109.4 | N2—C8—H8B | 109.2 |
N1—C1—H1B | 109.4 | C7—C8—H8B | 109.2 |
C2—C1—H1B | 109.4 | H8A—C8—H8B | 107.9 |
H1A—C1—H1B | 108.0 | N2—C9—C10 | 112.14 (8) |
C1—C2—C3 | 110.81 (9) | N2—C9—H9A | 109.2 |
C1—C2—H2A | 109.5 | C10—C9—H9A | 109.2 |
C3—C2—H2A | 109.5 | N2—C9—H9B | 109.2 |
C1—C2—H2B | 109.5 | C10—C9—H9B | 109.2 |
C3—C2—H2B | 109.5 | H9A—C9—H9B | 107.9 |
H2A—C2—H2B | 108.1 | C9—C10—C6 | 111.10 (8) |
C4—C3—C2 | 109.76 (9) | C9—C10—H10A | 109.4 |
C4—C3—H3A | 109.7 | C6—C10—H10A | 109.4 |
C2—C3—H3A | 109.7 | C9—C10—H10B | 109.4 |
C4—C3—H3B | 109.7 | C6—C10—H10B | 109.4 |
C2—C3—H3B | 109.7 | H10A—C10—H10B | 108.0 |
H3A—C3—H3B | 108.2 | N2—C11—C16 | 121.86 (9) |
C3—C4—C5 | 111.16 (10) | N2—C11—C12 | 120.57 (9) |
C3—C4—H4A | 109.4 | C16—C11—C12 | 117.55 (9) |
C5—C4—H4A | 109.4 | C13—C12—C11 | 121.27 (9) |
C3—C4—H4B | 109.4 | C13—C12—H12 | 119.4 |
C5—C4—H4B | 109.4 | C11—C12—H12 | 119.4 |
H4A—C4—H4B | 108.0 | C12—C13—C14 | 120.46 (9) |
N1—C5—C4 | 110.24 (9) | C12—C13—H13 | 119.8 |
N1—C5—H5A | 109.6 | C14—C13—H13 | 119.8 |
C4—C5—H5A | 109.6 | C15—C14—C13 | 118.98 (9) |
N1—C5—H5B | 109.6 | C15—C14—C17 | 120.39 (9) |
C4—C5—H5B | 109.6 | C13—C14—C17 | 120.63 (9) |
H5A—C5—H5B | 108.1 | C16—C15—C14 | 120.57 (9) |
N1—C6—C10 | 112.59 (8) | C16—C15—H15 | 119.7 |
N1—C6—C7 | 116.67 (8) | C14—C15—H15 | 119.7 |
C10—C6—C7 | 107.60 (8) | C15—C16—C11 | 121.17 (9) |
N1—C6—H6 | 106.4 | C15—C16—H16 | 119.4 |
C10—C6—H6 | 106.4 | C11—C16—H16 | 119.4 |
C7—C6—H6 | 106.4 | N3—C17—C14 | 179.37 (11) |
C8—C7—C6 | 111.06 (8) | ||
C5—N1—C1—C2 | −60.67 (11) | N2—C9—C10—C6 | 56.38 (12) |
C6—N1—C1—C2 | 171.35 (8) | N1—C6—C10—C9 | 172.41 (8) |
N1—C1—C2—C3 | 56.80 (12) | C7—C6—C10—C9 | −57.65 (11) |
C1—C2—C3—C4 | −52.73 (12) | C8—N2—C11—C16 | −0.48 (13) |
C2—C3—C4—C5 | 53.76 (12) | C9—N2—C11—C16 | 135.34 (10) |
C1—N1—C5—C4 | 60.92 (12) | C8—N2—C11—C12 | 178.25 (9) |
C6—N1—C5—C4 | −172.56 (9) | C9—N2—C11—C12 | −45.93 (12) |
C3—C4—C5—N1 | −58.25 (12) | N2—C11—C12—C13 | −179.30 (9) |
C5—N1—C6—C10 | 63.26 (11) | C16—C11—C12—C13 | −0.52 (14) |
C1—N1—C6—C10 | −171.10 (8) | C11—C12—C13—C14 | 0.37 (15) |
C5—N1—C6—C7 | −61.87 (12) | C12—C13—C14—C15 | −0.13 (15) |
C1—N1—C6—C7 | 63.77 (11) | C12—C13—C14—C17 | −179.78 (9) |
N1—C6—C7—C8 | −174.76 (8) | C13—C14—C15—C16 | 0.05 (15) |
C10—C6—C7—C8 | 57.63 (11) | C17—C14—C15—C16 | 179.70 (9) |
C11—N2—C8—C7 | −169.71 (8) | C14—C15—C16—C11 | −0.21 (15) |
C9—N2—C8—C7 | 53.24 (11) | N2—C11—C16—C15 | 179.21 (9) |
C6—C7—C8—N2 | −56.30 (11) | C12—C11—C16—C15 | 0.44 (15) |
C11—N2—C9—C10 | 169.02 (8) | C15—C14—C17—N3 | 38 (9) |
C8—N2—C9—C10 | −53.35 (11) | C13—C14—C17—N3 | −142 (9) |
Cg is the centroid of the C11–C16 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6···Cgi | 1.00 | 2.99 | 3.9363 (14) | 158 |
C16—H16···N3ii | 0.95 | 2.54 | 3.3442 (16) | 143 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, −y+1/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C17H23N3 |
Mr | 269.38 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 113 |
a, b, c (Å) | 10.090 (2), 11.100 (2), 13.446 (3) |
β (°) | 100.72 (3) |
V (Å3) | 1479.7 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.07 |
Crystal size (mm) | 0.26 × 0.25 × 0.20 |
Data collection | |
Diffractometer | Rigaku Saturn CCD area-detector |
Absorption correction | Multi-scan (CrystalClear; Rigaku/MSC, 2005) |
Tmin, Tmax | 0.981, 0.986 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11970, 3500, 2749 |
Rint | 0.032 |
(sin θ/λ)max (Å−1) | 0.658 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.111, 1.12 |
No. of reflections | 3500 |
No. of parameters | 182 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.27, −0.19 |
Computer programs: CrystalClear (Rigaku/MSC, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ChemBioDraw Ultra (CambridgeSoft, 2008).
Cg is the centroid of the C11–C16 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6···Cgi | 1.00 | 2.99 | 3.9363 (14) | 158 |
C16—H16···N3ii | 0.95 | 2.54 | 3.3442 (16) | 143 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, −y+1/2, z+1/2. |
Acknowledgements
The authors thank Mr Zhi-Hua Mao of Sichuan University for the X-ray data collection.
References
CambridgeSoft (2008). ChemBioDraw Ultra. CambridgeSoft, England. Google Scholar
Pevarello, P., Fancelli, D., Vulpetti, A., Amici, R., Villa, M., Pittalà, V., Vianello, P., Cameron, A., Ciomei, M., Mercurio, C., Bischoff, J. R., Roletto, F., Varasi, M. & Brasca, M. G. (2006). Bioorg. Med. Chem. Lett. 16, 1084–1090. Web of Science CrossRef PubMed CAS Google Scholar
Rigaku/MSC (2005). CrystalClear. Rigaku/MSC, The Woodlands, Texas, USA. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
4-(4-(Piperidin-1-yl)piperidin-1-yl)benzonitrile are key intermediates which can be used to synthesize 3-aminopyrazole derivatives, which can be used as precursors for anticancer and anti-malarial agents. In the structure of the title molecule (Fig. 1) both piperidine rings are in a chair conformation. A crystal packing is dominated by van der Waals interactions (Fig. 2).