organic compounds
1,3-Dicyclohexylimidazolidine-2,4,5-trione: a second polymorph
aDepartment of Chemistry, University of Aveiro, QOPNA, 3810-193 Aveiro, Portugal, and bDepartment of Chemistry, University of Aveiro, CICECO, 3810-193 Aveiro, Portugal
*Correspondence e-mail: artur.silva@ua.pt, filipe.paz@ua.pt
The title compound, C15H22N2O3, was obtained as a by-product of oxidative cleavage of 1,3-dicyclohexyl-(3-oxo-2,3-dihydrobenzofuran-2-yl)imidazolidine-2,4-dione. Herein, we report the of a second polymorph, which was obtained by crystallization from an ethanol solution at 253 K, instead of slow evaporation of the same solvent at room temperature. While the first polymorph [Talhi et al. (2011). Acta Cryst. E67, o3243] crystallized in the non-centrosymmetric P212121, this second polymorph crystallizes in the centrosymmetric P21/n. Compared to the first polymorph, in the crystal no C=O⋯C=O interactions were found (C⋯O intermolecular distance longer than 3.15 Å) and instead, close packing of individual molecular units is mediated by C—H⋯π and weak C—H⋯O interactions.
Related literature
For the structure of the orthorhombic polymorph and further background information to the study, see: Talhi et al. (2011). For general background on crystallographic studies by our research group of related compounds having biological activity, see: Fernandes et al. (2011); Loughzail et al. (2011). For determination of the melting point, see: Ulrichan & Sayigh (1965).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2006); cell SAINT-Plus (Bruker, 2005); data reduction: SAINT-Plus (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2009); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
Supporting information
10.1107/S1600536812043619/nk2188sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812043619/nk2188Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812043619/nk2188Isup3.cdx
Supporting information file. DOI: 10.1107/S1600536812043619/nk2188Isup4.cml
The title compound was prepared following the procedure described previously (Talhi et al., 2011), except for the crystallization process in which the raw compound was dissolved in ethanol and crystallized at 253 K overnight.
The melting point was measured on a Buchi B-540 equipment. NMR spectra were recorded on a Bruker Avance 300 spectrometer (300.13 for 1H and 75.47 MHz for 13C), with CDCl3 used as solvent. Chemical shifts (δ) are reported in p.p.m. and coupling constants (J) in Hz. The internal standard was TMS.
Unequivocal 13C assignments have been performed with the aid of bidimensional experiments (HSQC and HMBC). Both 1H and 13C NMR spectra show bilateral symmetry of the compound in solution. The HSQC spectrum allowed to deduce the electronegative effect of the nitrogen atom on the cyclohexyl proton and carbon resonances. However, it was found that the anisotropic effects of the carbonyl groups influence greatly the
values of the cyclohexyl proton resonances. Both of the highlighted effects of the parabanic nucleus heteroatoms are spread throughout the cyclohexyl chair skeleton decreasing gradually from C-1' to C-4'. Important features are recorded in the HMBC experiment concerning the carbon neighboring of the tertiary proton H-1' which correlates with the carbonyl groups C-2 and C-5, and further with C-2' and C-3' of the cyclohexyl radical.Elemental Analysis: Calculated (in %): C, 64.73; H, 7.97; N, 10.06; Found: C, 64.47; H, 7.96; N, 10.05.
Melting point: 175 °C (Lit [Ulrichan & Sayigh, 1965] 174–175 °C).
HRMS(ESI+): m/z Calcd for [C15H22N2O3 + Na]+: 301.1528; found 301.1523.
1H NMR (300.13 MHz, CDCl3): δ = 1.14–1.26 and 1.63–1.71 (2 m, 4 H, H-4'), 1.26–1.43 and 1.80–1.91 (2 m, 4 H, H-3'), 1.73–1.77 and 1.97–2.19 (2 m, 4 H, H-2'), 4.00 (tt, J= 12.0 and 3.7 Hz, 2 H, H-1') p.p.m..
13C NMR (75.47 MHz, CDCl3): δ = 24.7 (C-4'), 25.6 (C-3'), 29.5 (C-2'), 52.4 (C-1'), 153.4 (C-2), 156.4 (C-4,5) p.p.m..
Hydrogen atoms bound to carbon were placed in idealized positions with C—H = 1.00 (for the tertiary carbons) and 0.99 Å (for the —CH2— moieties). These atoms were included in the final structural model in riding-motion approximation with the isotropic thermal displacement parameters fixed at 1.2×Ueq of the carbon atom to which they are attached.
Data collection: APEX2 (Bruker, 2006); cell
SAINT-Plus (Bruker, 2005); data reduction: SAINT-Plus (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2009); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C15H22N2O3 | F(000) = 600 |
Mr = 278.35 | Dx = 1.278 Mg m−3 |
Monoclinic, P21/n | Melting point: 175 K |
Hall symbol: -P 2yn | Mo Kα radiation, λ = 0.71073 Å |
a = 5.1980 (2) Å | Cell parameters from 3876 reflections |
b = 21.7123 (10) Å | θ = 3.7–29.1° |
c = 13.0244 (6) Å | µ = 0.09 mm−1 |
β = 100.163 (2)° | T = 150 K |
V = 1446.88 (11) Å3 | Block, yellow |
Z = 4 | 0.13 × 0.06 × 0.06 mm |
Bruker X8 Kappa CCD APEXII diffractometer | 3876 independent reflections |
Radiation source: fine-focus sealed tube | 2999 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.049 |
ω and ϕ scans | θmax = 29.1°, θmin = 3.7° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1998) | h = −6→7 |
Tmin = 0.989, Tmax = 0.995 | k = −29→29 |
38115 measured reflections | l = −17→17 |
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)] = 0.043 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.104 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0374P)2 + 0.6588P] where P = (Fo2 + 2Fc2)/3 |
3876 reflections | (Δ/σ)max = 0.001 |
181 parameters | Δρmax = 0.37 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
C15H22N2O3 | V = 1446.88 (11) Å3 |
Mr = 278.35 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 5.1980 (2) Å | µ = 0.09 mm−1 |
b = 21.7123 (10) Å | T = 150 K |
c = 13.0244 (6) Å | 0.13 × 0.06 × 0.06 mm |
β = 100.163 (2)° |
Bruker X8 Kappa CCD APEXII diffractometer | 3876 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1998) | 2999 reflections with I > 2σ(I) |
Tmin = 0.989, Tmax = 0.995 | Rint = 0.049 |
38115 measured reflections |
R[F2 > 2σ(F2)] = 0.043 | 0 restraints |
wR(F2) = 0.104 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.37 e Å−3 |
3876 reflections | Δρmin = −0.18 e Å−3 |
181 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 | 0.9734 (2) | 0.59882 (5) | 0.12018 (9) | 0.0179 (2) | |
C2 | 0.7011 (2) | 0.59707 (6) | 0.23971 (10) | 0.0187 (2) | |
C3 | 0.6479 (2) | 0.65531 (6) | 0.17166 (10) | 0.0189 (2) | |
C4 | 0.8265 (2) | 0.69411 (5) | 0.01391 (9) | 0.0182 (2) | |
H4 | 0.9641 | 0.6788 | −0.0245 | 0.022* | |
C5 | 0.9020 (3) | 0.75914 (6) | 0.05202 (10) | 0.0225 (3) | |
H5A | 1.0763 | 0.7585 | 0.0973 | 0.027* | |
H5B | 0.7740 | 0.7748 | 0.0937 | 0.027* | |
C6 | 0.9077 (3) | 0.80176 (6) | −0.04117 (11) | 0.0246 (3) | |
H6A | 0.9480 | 0.8442 | −0.0157 | 0.030* | |
H6B | 1.0482 | 0.7883 | −0.0785 | 0.030* | |
C7 | 0.6476 (3) | 0.80154 (6) | −0.11652 (10) | 0.0224 (3) | |
H7A | 0.5098 | 0.8190 | −0.0815 | 0.027* | |
H7B | 0.6613 | 0.8278 | −0.1775 | 0.027* | |
C8 | 0.5724 (3) | 0.73639 (6) | −0.15326 (10) | 0.0255 (3) | |
H8A | 0.7001 | 0.7208 | −0.1951 | 0.031* | |
H8B | 0.3982 | 0.7371 | −0.1986 | 0.031* | |
C9 | 0.5654 (3) | 0.69293 (6) | −0.06145 (10) | 0.0235 (3) | |
H9A | 0.4236 | 0.7056 | −0.0242 | 0.028* | |
H9B | 0.5282 | 0.6505 | −0.0877 | 0.028* | |
C10 | 1.0256 (2) | 0.50852 (5) | 0.24346 (10) | 0.0185 (2) | |
H10 | 1.1926 | 0.5048 | 0.2158 | 0.022* | |
C11 | 1.0949 (3) | 0.50699 (6) | 0.36255 (10) | 0.0227 (3) | |
H11A | 0.9339 | 0.5107 | 0.3929 | 0.027* | |
H11B | 1.2105 | 0.5421 | 0.3876 | 0.027* | |
C12 | 1.2335 (3) | 0.44639 (6) | 0.39731 (11) | 0.0257 (3) | |
H12A | 1.4008 | 0.4443 | 0.3711 | 0.031* | |
H12B | 1.2733 | 0.4448 | 0.4744 | 0.031* | |
C13 | 1.0635 (3) | 0.39147 (6) | 0.35622 (13) | 0.0334 (3) | |
H13A | 0.9026 | 0.3916 | 0.3871 | 0.040* | |
H13B | 1.1593 | 0.3528 | 0.3773 | 0.040* | |
C14 | 0.9900 (3) | 0.39390 (6) | 0.23745 (13) | 0.0351 (4) | |
H14A | 0.8732 | 0.3589 | 0.2129 | 0.042* | |
H14B | 1.1499 | 0.3897 | 0.2065 | 0.042* | |
C15 | 0.8525 (3) | 0.45432 (6) | 0.20050 (11) | 0.0263 (3) | |
H15A | 0.8176 | 0.4558 | 0.1233 | 0.032* | |
H15B | 0.6832 | 0.4569 | 0.2251 | 0.032* | |
N1 | 0.9031 (2) | 0.56747 (5) | 0.20531 (8) | 0.0185 (2) | |
N2 | 0.8172 (2) | 0.65170 (5) | 0.10196 (8) | 0.0182 (2) | |
O1 | 1.13883 (18) | 0.58316 (4) | 0.07174 (7) | 0.0244 (2) | |
O2 | 0.58424 (18) | 0.58220 (4) | 0.30792 (7) | 0.0260 (2) | |
O3 | 0.49016 (18) | 0.69488 (4) | 0.18021 (8) | 0.0259 (2) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0198 (6) | 0.0174 (5) | 0.0157 (6) | −0.0008 (4) | 0.0015 (5) | 0.0002 (4) |
C2 | 0.0183 (6) | 0.0194 (5) | 0.0182 (6) | −0.0008 (4) | 0.0023 (5) | −0.0007 (4) |
C3 | 0.0186 (6) | 0.0201 (6) | 0.0178 (6) | −0.0009 (5) | 0.0025 (5) | 0.0005 (5) |
C4 | 0.0201 (6) | 0.0183 (5) | 0.0160 (6) | 0.0007 (4) | 0.0031 (5) | 0.0049 (4) |
C5 | 0.0232 (7) | 0.0206 (6) | 0.0215 (6) | −0.0030 (5) | −0.0022 (5) | 0.0030 (5) |
C6 | 0.0228 (7) | 0.0216 (6) | 0.0283 (7) | −0.0030 (5) | 0.0012 (5) | 0.0060 (5) |
C7 | 0.0218 (6) | 0.0223 (6) | 0.0227 (6) | 0.0025 (5) | 0.0030 (5) | 0.0060 (5) |
C8 | 0.0282 (7) | 0.0262 (6) | 0.0198 (6) | −0.0003 (5) | −0.0019 (5) | 0.0037 (5) |
C9 | 0.0244 (7) | 0.0227 (6) | 0.0213 (6) | −0.0048 (5) | −0.0022 (5) | 0.0024 (5) |
C10 | 0.0209 (6) | 0.0165 (5) | 0.0182 (6) | 0.0023 (4) | 0.0041 (5) | 0.0021 (4) |
C11 | 0.0272 (7) | 0.0213 (6) | 0.0189 (6) | 0.0027 (5) | 0.0023 (5) | 0.0016 (5) |
C12 | 0.0277 (7) | 0.0278 (6) | 0.0210 (6) | 0.0061 (5) | 0.0026 (5) | 0.0055 (5) |
C13 | 0.0327 (8) | 0.0228 (7) | 0.0434 (9) | 0.0033 (6) | 0.0036 (7) | 0.0134 (6) |
C14 | 0.0391 (8) | 0.0171 (6) | 0.0442 (9) | 0.0011 (6) | −0.0062 (7) | −0.0031 (6) |
C15 | 0.0297 (7) | 0.0187 (6) | 0.0279 (7) | 0.0001 (5) | −0.0025 (6) | −0.0008 (5) |
N1 | 0.0214 (5) | 0.0175 (5) | 0.0176 (5) | 0.0015 (4) | 0.0059 (4) | 0.0019 (4) |
N2 | 0.0196 (5) | 0.0176 (5) | 0.0178 (5) | 0.0020 (4) | 0.0044 (4) | 0.0027 (4) |
O1 | 0.0287 (5) | 0.0242 (4) | 0.0225 (5) | 0.0060 (4) | 0.0105 (4) | 0.0031 (4) |
O2 | 0.0259 (5) | 0.0288 (5) | 0.0255 (5) | 0.0017 (4) | 0.0110 (4) | 0.0057 (4) |
O3 | 0.0251 (5) | 0.0254 (5) | 0.0284 (5) | 0.0074 (4) | 0.0079 (4) | 0.0030 (4) |
C1—O1 | 1.2017 (15) | C8—H8A | 0.9900 |
C1—N2 | 1.4022 (15) | C8—H8B | 0.9900 |
C1—N1 | 1.4033 (15) | C9—H9A | 0.9900 |
C2—O2 | 1.2052 (15) | C9—H9B | 0.9900 |
C2—N1 | 1.3723 (16) | C10—N1 | 1.4760 (15) |
C2—C3 | 1.5409 (17) | C10—C15 | 1.5262 (17) |
C3—O3 | 1.2062 (15) | C10—C11 | 1.5296 (17) |
C3—N2 | 1.3734 (16) | C10—H10 | 1.0000 |
C4—N2 | 1.4781 (15) | C11—C12 | 1.5297 (18) |
C4—C5 | 1.5250 (17) | C11—H11A | 0.9900 |
C4—C9 | 1.5284 (18) | C11—H11B | 0.9900 |
C4—H4 | 1.0000 | C12—C13 | 1.524 (2) |
C5—C6 | 1.5307 (18) | C12—H12A | 0.9900 |
C5—H5A | 0.9900 | C12—H12B | 0.9900 |
C5—H5B | 0.9900 | C13—C14 | 1.527 (2) |
C6—C7 | 1.5239 (18) | C13—H13A | 0.9900 |
C6—H6A | 0.9900 | C13—H13B | 0.9900 |
C6—H6B | 0.9900 | C14—C15 | 1.5302 (19) |
C7—C8 | 1.5220 (18) | C14—H14A | 0.9900 |
C7—H7A | 0.9900 | C14—H14B | 0.9900 |
C7—H7B | 0.9900 | C15—H15A | 0.9900 |
C8—C9 | 1.5288 (18) | C15—H15B | 0.9900 |
O1—C1—N2 | 126.12 (11) | H9A—C9—H9B | 108.1 |
O1—C1—N1 | 126.00 (11) | N1—C10—C15 | 110.74 (10) |
N2—C1—N1 | 107.88 (10) | N1—C10—C11 | 111.77 (10) |
O2—C2—N1 | 129.00 (12) | C15—C10—C11 | 111.92 (10) |
O2—C2—C3 | 125.55 (11) | N1—C10—H10 | 107.4 |
N1—C2—C3 | 105.45 (10) | C15—C10—H10 | 107.4 |
O3—C3—N2 | 128.81 (12) | C11—C10—H10 | 107.4 |
O3—C3—C2 | 125.96 (11) | C10—C11—C12 | 109.47 (10) |
N2—C3—C2 | 105.22 (10) | C10—C11—H11A | 109.8 |
N2—C4—C5 | 111.47 (10) | C12—C11—H11A | 109.8 |
N2—C4—C9 | 109.93 (10) | C10—C11—H11B | 109.8 |
C5—C4—C9 | 111.89 (10) | C12—C11—H11B | 109.8 |
N2—C4—H4 | 107.8 | H11A—C11—H11B | 108.2 |
C5—C4—H4 | 107.8 | C13—C12—C11 | 110.82 (11) |
C9—C4—H4 | 107.8 | C13—C12—H12A | 109.5 |
C4—C5—C6 | 109.97 (10) | C11—C12—H12A | 109.5 |
C4—C5—H5A | 109.7 | C13—C12—H12B | 109.5 |
C6—C5—H5A | 109.7 | C11—C12—H12B | 109.5 |
C4—C5—H5B | 109.7 | H12A—C12—H12B | 108.1 |
C6—C5—H5B | 109.7 | C12—C13—C14 | 110.77 (12) |
H5A—C5—H5B | 108.2 | C12—C13—H13A | 109.5 |
C7—C6—C5 | 111.69 (11) | C14—C13—H13A | 109.5 |
C7—C6—H6A | 109.3 | C12—C13—H13B | 109.5 |
C5—C6—H6A | 109.3 | C14—C13—H13B | 109.5 |
C7—C6—H6B | 109.3 | H13A—C13—H13B | 108.1 |
C5—C6—H6B | 109.3 | C13—C14—C15 | 111.56 (12) |
H6A—C6—H6B | 107.9 | C13—C14—H14A | 109.3 |
C8—C7—C6 | 110.79 (11) | C15—C14—H14A | 109.3 |
C8—C7—H7A | 109.5 | C13—C14—H14B | 109.3 |
C6—C7—H7A | 109.5 | C15—C14—H14B | 109.3 |
C8—C7—H7B | 109.5 | H14A—C14—H14B | 108.0 |
C6—C7—H7B | 109.5 | C10—C15—C14 | 109.49 (11) |
H7A—C7—H7B | 108.1 | C10—C15—H15A | 109.8 |
C7—C8—C9 | 111.59 (11) | C14—C15—H15A | 109.8 |
C7—C8—H8A | 109.3 | C10—C15—H15B | 109.8 |
C9—C8—H8A | 109.3 | C14—C15—H15B | 109.8 |
C7—C8—H8B | 109.3 | H15A—C15—H15B | 108.2 |
C9—C8—H8B | 109.3 | C2—N1—C1 | 110.60 (10) |
H8A—C8—H8B | 108.0 | C2—N1—C10 | 127.27 (10) |
C4—C9—C8 | 110.55 (11) | C1—N1—C10 | 121.98 (10) |
C4—C9—H9A | 109.5 | C3—N2—C1 | 110.76 (10) |
C8—C9—H9A | 109.5 | C3—N2—C4 | 126.14 (10) |
C4—C9—H9B | 109.5 | C1—N2—C4 | 122.96 (10) |
C8—C9—H9B | 109.5 | ||
O2—C2—C3—O3 | 3.1 (2) | O2—C2—N1—C10 | 1.1 (2) |
N1—C2—C3—O3 | −177.10 (12) | C3—C2—N1—C10 | −178.71 (11) |
O2—C2—C3—N2 | −177.10 (12) | O1—C1—N1—C2 | −177.91 (12) |
N1—C2—C3—N2 | 2.67 (13) | N2—C1—N1—C2 | 2.28 (14) |
N2—C4—C5—C6 | −179.59 (10) | O1—C1—N1—C10 | −1.95 (19) |
C9—C4—C5—C6 | −56.03 (14) | N2—C1—N1—C10 | 178.24 (10) |
C4—C5—C6—C7 | 56.11 (15) | C15—C10—N1—C2 | 76.87 (15) |
C5—C6—C7—C8 | −56.18 (15) | C11—C10—N1—C2 | −48.64 (16) |
C6—C7—C8—C9 | 55.57 (15) | C15—C10—N1—C1 | −98.38 (13) |
N2—C4—C9—C8 | −179.76 (10) | C11—C10—N1—C1 | 136.10 (12) |
C5—C4—C9—C8 | 55.82 (14) | O3—C3—N2—C1 | 178.39 (13) |
C7—C8—C9—C4 | −55.24 (15) | C2—C3—N2—C1 | −1.36 (13) |
N1—C10—C11—C12 | −177.09 (10) | O3—C3—N2—C4 | −5.9 (2) |
C15—C10—C11—C12 | 58.05 (14) | C2—C3—N2—C4 | 174.36 (11) |
C10—C11—C12—C13 | −57.32 (15) | O1—C1—N2—C3 | 179.78 (12) |
C11—C12—C13—C14 | 57.00 (16) | N1—C1—N2—C3 | −0.41 (14) |
C12—C13—C14—C15 | −56.42 (17) | O1—C1—N2—C4 | 3.89 (19) |
N1—C10—C15—C14 | 177.51 (12) | N1—C1—N2—C4 | −176.29 (10) |
C11—C10—C15—C14 | −57.06 (15) | C5—C4—N2—C3 | 64.30 (16) |
C13—C14—C15—C10 | 55.77 (17) | C9—C4—N2—C3 | −60.36 (15) |
O2—C2—N1—C1 | 176.75 (13) | C5—C4—N2—C1 | −120.46 (12) |
C3—C2—N1—C1 | −3.01 (13) | C9—C4—N2—C1 | 114.87 (13) |
Cg is the centroid of the N1, N2, C1–C3 ring. <[C—H···(ring plane)] is ca. 43°. |
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7B···Cgi | 0.99 | 2.78 | 3.5511 (14) | 135 |
C11—H11B···O2ii | 0.99 | 2.51 | 3.2065 (18) | 127 |
Symmetry codes: (i) x−1/2, −y+3/2, z−1/2; (ii) x+1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C15H22N2O3 |
Mr | 278.35 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 150 |
a, b, c (Å) | 5.1980 (2), 21.7123 (10), 13.0244 (6) |
β (°) | 100.163 (2) |
V (Å3) | 1446.88 (11) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.13 × 0.06 × 0.06 |
Data collection | |
Diffractometer | Bruker X8 Kappa CCD APEXII diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1998) |
Tmin, Tmax | 0.989, 0.995 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 38115, 3876, 2999 |
Rint | 0.049 |
(sin θ/λ)max (Å−1) | 0.685 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.043, 0.104, 1.04 |
No. of reflections | 3876 |
No. of parameters | 181 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.37, −0.18 |
Computer programs: APEX2 (Bruker, 2006), SAINT-Plus (Bruker, 2005), SHELXTL (Sheldrick, 2008), DIAMOND (Brandenburg, 2009).
Cg is the centroid of the N1, N2, C1–C3 ring. <[C—H···(ring plane)] is ca. 43°. |
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7B···Cgi | 0.99 | 2.78 | 3.5511 (14) | 135 |
C11—H11B···O2ii | 0.99 | 2.51 | 3.2065 (18) | 127 |
Symmetry codes: (i) x−1/2, −y+3/2, z−1/2; (ii) x+1, y, z. |
Acknowledgements
The authors gratefully acknowledge the Fundação para a Ciência e a Tecnologia (FCT, MEC, Portugal), the European Union, QREN, FEDER, COMPETE for financial support by the strategic projects PEst-C/CTM/LA0011/2011 (to CICECO) and PEst-C/QUI/UI0062/2011 (to QOPNA), the R&D project PTDC/QUI-QUI/098098/2008 (FCOMP-01–0124-FEDER-010785), as well as the post-doctoral research grant SFRH/BPD/63736/2009 (to JAF). We further wish to thank the FCT for specific funding towards the purchase of the single-crystal X-ray diffractometer. We also thank the European Community's Seventh Framework Programme (FP7/2007–20139 under grant agreement No. 215009).
References
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In a previous publication (Talhi et al., 2011) we described the crystal structure (polymorph I) of 1,3-dicyclohexylparabanic acid (see chemical diagram and Figure 1) obtained as a by-product of the oxidative cleavage of the C2'-C5 single bond of 1,3-dicyclohexyl-(3-oxo-2,3-dihydrobenzofuran-2-yl)imidazolidine-2,4-dione, using catalytic I2/DMSO system at 463 K. Following our interest on the structural features of compounds having biological activity (Fernandes et al., 2011; Loughzail et al. 2011; Talhi et al., 2011), particularly in our quest for novel polymorphic forms of pharmaceutic products, we wish to report the structure of a second crystalline polymorph of the title compound (polymorph II) obtained when applying a different crystallization procedure from that previously reported by us: while polymorph I was obtained by slow evaporation of an ethanolic solution at room temperature, polymorph II was obtained instead by cooling overnight the same solution at 253 K.
The asymmetric unit comprises a whole molecular unit of the title compound, C15H22N2O3 (Scheme and Figure 1). The central parabanic acid residue and the attached carbon atoms are coplanar with the largest deviation from the medium plane being 0.075 (1) Å for C4. The two cyclohexyl substituent groups appear exhibiting the chair typical conformation and their medium planes subtend slightly different angles with the aforementioned central plane, being one almost perpendicular [88.73 (5)°] and the other of 74.15 (6)°. We note that the observed angles for these two planes are larger than those registered for polymorph I in which the analogous values are ca 81 and 87° (Talhi et al., 2011). Remarkably the four possible N—C—C—C groups involving three adjacent carbon atoms of the cyclohexyl moieties are also very near the planarity [largest deviation of 0.019 (1) Å for C10 in N1—C10—C11—C12].
The crystal packing is mainly governed by the need to fill the available space. A handful of weak supramolecular interactions are also observed, namely C—H···π and C—H···O (See Table 1 and Figure 2). While in the crystal structure of polymorph I a strong C═O···C═O interaction with a C···O distance smaller than 2.871 Å was observed, in the present polymorph II the shortest C···O intermolecular distance is 3.1519 (15) Å, which, in comparison to the case of polymorph I, may be considered as negligible.