Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270105021608/ta1498sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270105021608/ta1498Isup2.hkl |
CCDC reference: 282211
The title compound was synthesized by nucleophilic replacement of bromine at the 5-position of the imidazole ring by piperidine (see scheme). The reaction was carried out in boiling methanol with an excess of piperidine over 24 h with a high yield. In contrast with the reactivity of the 1-alkyl derivative, in which double substitution of the bromo and nitro groups was observed (Kulkarni et al., 1987), the arene substituent significantly decreases the reactivity of the imidazole moiety. Crystals of (I) for X-ray data collection were grown from a methanol solution.
The positions of the H atoms were freely refined. For each group of these atoms, i.e. for the methyl group, for each CH2 group and for ring H atoms, one common Uiso(H) parameter was refined.
Data collection: CrysAlis CCD (Oxford Diffraction, 2002); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Stereochemical Workstation Operation Manual (Siemens, 1989); software used to prepare material for publication: SHELXL97.
C15H17ClN4O2 | F(000) = 672 |
Mr = 320.78 | Dx = 1.466 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 2320 reflections |
a = 8.5841 (12) Å | θ = 3–20° |
b = 9.0352 (12) Å | µ = 0.28 mm−1 |
c = 18.738 (2) Å | T = 90 K |
V = 1453.3 (3) Å3 | Needle, colourless |
Z = 4 | 0.4 × 0.15 × 0.1 mm |
Kuma KM4 CCD four-circle diffractometer | 4072 independent reflections |
Radiation source: fine-focus sealed tube | 3298 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.027 |
ω scans | θmax = 30.0°, θmin = 3.1° |
Absorption correction: multi-scan (SORTAV; Blessing, 1989) | h = −12→12 |
Tmin = 0.958, Tmax = 0.972 | k = −12→12 |
15516 measured reflections | l = −25→23 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.031 | All H-atom parameters refined |
wR(F2) = 0.054 | w = 1/[σ2(Fo2) + (0.021P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.93 | (Δ/σ)max = 0.008 |
4069 reflections | Δρmax = 0.25 e Å−3 |
257 parameters | Δρmin = −0.22 e Å−3 |
0 restraints | Absolute structure: Flack (1983), with how many Friedel pairs? |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.03 (4) |
C15H17ClN4O2 | V = 1453.3 (3) Å3 |
Mr = 320.78 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 8.5841 (12) Å | µ = 0.28 mm−1 |
b = 9.0352 (12) Å | T = 90 K |
c = 18.738 (2) Å | 0.4 × 0.15 × 0.1 mm |
Kuma KM4 CCD four-circle diffractometer | 4072 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1989) | 3298 reflections with I > 2σ(I) |
Tmin = 0.958, Tmax = 0.972 | Rint = 0.027 |
15516 measured reflections |
R[F2 > 2σ(F2)] = 0.031 | All H-atom parameters refined |
wR(F2) = 0.054 | Δρmax = 0.25 e Å−3 |
S = 0.93 | Δρmin = −0.22 e Å−3 |
4069 reflections | Absolute structure: Flack (1983), with how many Friedel pairs? |
257 parameters | Absolute structure parameter: −0.03 (4) |
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. |
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 | 0.19042 (12) | 0.07948 (15) | 0.71631 (6) | 0.0126 (3) | |
C11 | 0.33192 (15) | 0.04219 (17) | 0.75320 (8) | 0.0124 (3) | |
C12 | 0.47264 (15) | 0.09400 (18) | 0.72753 (8) | 0.0137 (3) | |
H12 | 0.4765 (17) | 0.1533 (18) | 0.6841 (9) | 0.019 (2)* | |
C13 | 0.60879 (15) | 0.05860 (18) | 0.76298 (8) | 0.0157 (3) | |
H13 | 0.7086 (17) | 0.0936 (17) | 0.7448 (8) | 0.019 (2)* | |
C14 | 0.59994 (16) | −0.02462 (17) | 0.82484 (8) | 0.0150 (3) | |
Cl14 | 0.76976 (4) | −0.07192 (5) | 0.86936 (2) | 0.02338 (10) | |
C15 | 0.45927 (15) | −0.07465 (19) | 0.85163 (8) | 0.0142 (3) | |
H15 | 0.4595 (18) | −0.1330 (18) | 0.8939 (9) | 0.019 (2)* | |
C16 | 0.32332 (17) | −0.04355 (18) | 0.81422 (8) | 0.0140 (3) | |
H16 | 0.2236 (17) | −0.0833 (18) | 0.8289 (8) | 0.019 (2)* | |
C2 | 0.06975 (15) | 0.16119 (17) | 0.74527 (8) | 0.0148 (3) | |
C21 | 0.07373 (19) | 0.2204 (2) | 0.81911 (9) | 0.0213 (4) | |
H21A | −0.010 (2) | 0.293 (2) | 0.8260 (10) | 0.045 (3)* | |
H21B | 0.165 (2) | 0.271 (2) | 0.8307 (10) | 0.045 (3)* | |
H21C | 0.056 (2) | 0.140 (2) | 0.8538 (11) | 0.045 (3)* | |
N3 | −0.04125 (14) | 0.18348 (15) | 0.69922 (7) | 0.0159 (3) | |
C4 | 0.00696 (15) | 0.11221 (17) | 0.63817 (8) | 0.0144 (3) | |
N4 | −0.09856 (13) | 0.09276 (15) | 0.58097 (7) | 0.0178 (3) | |
O41 | −0.22275 (12) | 0.16262 (13) | 0.58280 (6) | 0.0239 (3) | |
O42 | −0.06557 (12) | 0.00420 (14) | 0.53316 (6) | 0.0246 (3) | |
C5 | 0.15393 (14) | 0.04953 (17) | 0.64545 (8) | 0.0133 (3) | |
N51 | 0.25744 (14) | −0.01388 (14) | 0.59974 (6) | 0.0143 (3) | |
C52 | 0.32780 (17) | −0.15815 (18) | 0.61540 (8) | 0.0149 (3) | |
H52A | 0.2683 (18) | −0.2385 (17) | 0.5884 (8) | 0.016 (3)* | |
H52B | 0.3182 (17) | −0.1755 (18) | 0.6671 (9) | 0.016 (3)* | |
C53 | 0.49641 (17) | −0.1627 (2) | 0.59020 (9) | 0.0173 (3) | |
H53A | 0.5566 (18) | −0.098 (2) | 0.6202 (9) | 0.024 (3)* | |
H53B | 0.5392 (19) | −0.263 (2) | 0.5973 (9) | 0.024 (3)* | |
C54 | 0.50843 (18) | −0.1180 (2) | 0.51212 (9) | 0.0195 (4) | |
H54A | 0.4547 (17) | −0.1915 (18) | 0.4839 (8) | 0.015 (3)* | |
H54B | 0.6182 (17) | −0.1056 (17) | 0.4983 (8) | 0.015 (3)* | |
C55 | 0.43086 (17) | 0.0315 (2) | 0.49973 (9) | 0.0180 (4) | |
H55A | 0.4873 (17) | 0.1138 (19) | 0.5230 (8) | 0.018 (3)* | |
H55B | 0.4351 (16) | 0.0596 (19) | 0.4499 (9) | 0.018 (3)* | |
C56 | 0.26227 (17) | 0.02967 (19) | 0.52466 (8) | 0.0170 (3) | |
H56A | 0.2142 (17) | 0.1267 (18) | 0.5202 (8) | 0.019 (3)* | |
H56B | 0.2013 (17) | −0.0394 (18) | 0.4944 (8) | 0.019 (3)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0101 (5) | 0.0132 (7) | 0.0145 (6) | 0.0013 (5) | 0.0005 (4) | 0.0004 (6) |
C11 | 0.0098 (5) | 0.0126 (9) | 0.0149 (7) | 0.0011 (5) | −0.0003 (5) | −0.0021 (6) |
C12 | 0.0146 (6) | 0.0117 (8) | 0.0148 (8) | −0.0019 (6) | 0.0011 (5) | −0.0005 (7) |
C13 | 0.0120 (6) | 0.0145 (9) | 0.0205 (8) | −0.0006 (6) | 0.0005 (5) | −0.0039 (7) |
C14 | 0.0129 (6) | 0.0135 (9) | 0.0186 (8) | 0.0029 (5) | −0.0052 (5) | −0.0060 (7) |
Cl14 | 0.01719 (15) | 0.0261 (2) | 0.0268 (2) | 0.00672 (16) | −0.00870 (15) | −0.00548 (19) |
C15 | 0.0182 (6) | 0.0109 (8) | 0.0134 (7) | 0.0024 (6) | 0.0000 (5) | −0.0003 (7) |
C16 | 0.0146 (6) | 0.0136 (9) | 0.0138 (7) | −0.0013 (6) | 0.0008 (5) | −0.0026 (6) |
C2 | 0.0113 (6) | 0.0128 (9) | 0.0205 (8) | 0.0008 (5) | 0.0034 (5) | 0.0001 (7) |
C21 | 0.0188 (8) | 0.0254 (11) | 0.0197 (9) | 0.0066 (7) | 0.0022 (6) | −0.0030 (8) |
N3 | 0.0131 (6) | 0.0170 (8) | 0.0177 (7) | 0.0020 (5) | 0.0006 (5) | 0.0013 (6) |
C4 | 0.0115 (6) | 0.0148 (9) | 0.0170 (8) | −0.0005 (5) | −0.0007 (5) | 0.0023 (7) |
N4 | 0.0129 (5) | 0.0192 (8) | 0.0214 (7) | −0.0003 (6) | −0.0010 (5) | 0.0031 (6) |
O41 | 0.0130 (5) | 0.0260 (7) | 0.0326 (7) | 0.0055 (5) | −0.0065 (5) | 0.0005 (5) |
O42 | 0.0189 (5) | 0.0306 (8) | 0.0245 (6) | 0.0017 (5) | −0.0038 (5) | −0.0077 (6) |
C5 | 0.0119 (6) | 0.0112 (8) | 0.0169 (8) | −0.0004 (5) | −0.0002 (5) | 0.0016 (6) |
N51 | 0.0136 (5) | 0.0154 (7) | 0.0139 (6) | 0.0044 (5) | 0.0017 (5) | 0.0021 (5) |
C52 | 0.0150 (6) | 0.0133 (9) | 0.0163 (8) | 0.0006 (6) | 0.0011 (6) | −0.0004 (7) |
C53 | 0.0162 (7) | 0.0171 (9) | 0.0186 (9) | 0.0050 (6) | 0.0012 (6) | 0.0011 (7) |
C54 | 0.0187 (7) | 0.0210 (10) | 0.0187 (9) | 0.0030 (6) | 0.0046 (6) | −0.0002 (7) |
C55 | 0.0179 (7) | 0.0202 (10) | 0.0160 (8) | 0.0019 (6) | 0.0030 (6) | 0.0025 (7) |
C56 | 0.0173 (7) | 0.0200 (10) | 0.0136 (7) | 0.0030 (6) | −0.0003 (6) | 0.0025 (6) |
N1—C2 | 1.383 (2) | C4—N4 | 1.414 (2) |
N1—C5 | 1.391 (2) | N4—O42 | 1.234 (2) |
N1—C11 | 1.438 (2) | N4—O41 | 1.239 (2) |
C11—C12 | 1.382 (2) | C5—N51 | 1.361 (2) |
C11—C16 | 1.383 (2) | N51—C56 | 1.462 (2) |
C12—C13 | 1.382 (2) | N51—C52 | 1.466 (2) |
C12—H12 | 0.98 (2) | C52—C53 | 1.523 (2) |
C13—C14 | 1.384 (2) | C52—H52A | 1.02 (2) |
C13—H13 | 0.97 (2) | C52—H52B | 0.98 (2) |
C14—C15 | 1.384 (2) | C53—C54 | 1.521 (2) |
C14—Cl14 | 1.733 (1) | C53—H53A | 0.96 (2) |
C15—C16 | 1.390 (2) | C53—H53B | 0.99 (2) |
C15—H15 | 0.95 (2) | C54—C55 | 1.524 (2) |
C16—H16 | 0.97 (2) | C54—H54A | 0.97 (2) |
C2—N3 | 1.301 (2) | C54—H54B | 0.98 (2) |
C2—C21 | 1.484 (2) | C55—C56 | 1.521 (2) |
C21—H21A | 0.98 (2) | C55—H55A | 0.99 (2) |
C21—H21B | 0.93 (2) | C55—H55B | 0.97 (2) |
C21—H21C | 0.99 (2) | C56—H56A | 0.97 (2) |
N3—C4 | 1.376 (2) | C56—H56B | 0.99 (2) |
C4—C5 | 1.390 (2) | ||
C2—N1—C5 | 108.1 (1) | N51—C5—C4 | 134.7 (1) |
C2—N1—C11 | 124.7 (1) | N51—C5—N1 | 122.4 (1) |
C5—N1—C11 | 127.1 (1) | C4—C5—N1 | 102.6 (1) |
C12—C11—C16 | 121.6 (1) | C5—N51—C56 | 120.7 (1) |
C12—C11—N1 | 119.5 (1) | C5—N51—C52 | 121.2 (1) |
C16—C11—N1 | 118.9 (1) | C56—N51—C52 | 114.9 (1) |
C13—C12—C11 | 119.6 (1) | N51—C52—C53 | 110.7 (1) |
C13—C12—H12 | 120.0 (9) | N51—C52—H52A | 109.1 (9) |
C11—C12—H12 | 120.4 (9) | C53—C52—H52A | 107.6 (9) |
C12—C13—C14 | 118.8 (1) | N51—C52—H52B | 107.7 (9) |
C12—C13—H13 | 120.0 (9) | C53—C52—H52B | 112.3 (9) |
C14—C13—H13 | 121.1 (9) | H52A—C52—H52B | 109 (1) |
C15—C14—C13 | 122.0 (1) | C54—C53—C52 | 110.8 (1) |
C15—C14—Cl14 | 118.6 (1) | C54—C53—H53A | 112 (1) |
C13—C14—Cl14 | 119.4 (1) | C52—C53—H53A | 108.3 (9) |
C14—C15—C16 | 118.9 (1) | C54—C53—H53B | 110 (1) |
C14—C15—H15 | 118.8 (9) | C52—C53—H53B | 110 (1) |
C16—C15—H15 | 122 (1) | H53A—C53—H53B | 106 (1) |
C11—C16—C15 | 119.0 (1) | C53—C54—C55 | 110.6 (1) |
C11—C16—H16 | 119.3 (9) | C53—C54—H54A | 108.1 (9) |
C15—C16—H16 | 121.6 (9) | C55—C54—H54A | 108.5 (9) |
N3—C2—N1 | 111.8 (1) | C53—C54—H54B | 110.4 (9) |
N3—C2—C21 | 125.4 (1) | C55—C54—H54B | 106.1 (9) |
N1—C2—C21 | 122.8 (1) | H54A—C54—H54B | 113 (1) |
C2—C21—H21A | 110 (1) | C56—C55—C54 | 111.1 (1) |
C2—C21—H21B | 115 (1) | C56—C55—H55A | 109.8 (9) |
H21A—C21—H21B | 105 (2) | C54—C55—H55A | 112.7 (9) |
C2—C21—H21C | 110 (1) | C56—C55—H55B | 109.6 (8) |
H21A—C21—H21C | 107 (2) | C54—C55—H55B | 111 (1) |
H21B—C21—H21C | 110 (2) | H55A—C55—H55B | 102 (1) |
C2—N3—C4 | 105.0 (1) | N51—C56—C55 | 109.0 (1) |
N3—C4—C5 | 112.5 (1) | N51—C56—H56A | 108.3 (9) |
N3—C4—N4 | 119.7 (1) | C55—C56—H56A | 111.6 (9) |
C5—C4—N4 | 127.2 (1) | N51—C56—H56B | 111.5 (9) |
O42—N4—O41 | 123.2 (1) | C55—C56—H56B | 109.5 (8) |
O42—N4—C4 | 118.9 (1) | H56A—C56—H56B | 107 (1) |
O41—N4—C4 | 117.8 (1) | ||
C2—N1—C11—C12 | −117.5 (2) | C5—C4—N4—O42 | 5.0 (2) |
C5—N1—C11—C12 | 58.1 (2) | N3—C4—N4—O41 | 12.1 (2) |
C2—N1—C11—C16 | 61.7 (2) | C5—C4—N4—O41 | −177.4 (1) |
C5—N1—C11—C16 | −122.6 (2) | N3—C4—C5—N51 | −170.3 (2) |
C16—C11—C12—C13 | 0.6 (2) | N4—C4—C5—N51 | 18.7 (3) |
N1—C11—C12—C13 | 179.9 (2) | N3—C4—C5—N1 | 3.1 (2) |
C11—C12—C13—C14 | −1.9 (2) | N4—C4—C5—N1 | −167.9 (1) |
C12—C13—C14—C15 | 0.8 (2) | C2—N1—C5—N51 | 172.0 (1) |
C12—C13—C14—Cl14 | 179.2 (1) | C11—N1—C5—N51 | −4.3 (2) |
C13—C14—C15—C16 | 1.7 (2) | C2—N1—C5—C4 | −2.5 (2) |
Cl14—C14—C15—C16 | −176.8 (1) | C11—N1—C5—C4 | −178.7 (1) |
C12—C11—C16—C15 | 1.8 (2) | C4—C5—N51—C56 | 28.5 (2) |
N1—C11—C16—C15 | −177.4 (1) | N1—C5—N51—C56 | −143.9 (2) |
C14—C15—C16—C11 | −3.0 (2) | C4—C5—N51—C52 | −130.1 (2) |
C5—N1—C2—N3 | 1.1 (2) | N1—C5—N51—C52 | 57.5 (2) |
C11—N1—C2—N3 | 177.4 (1) | C5—N51—C52—C53 | −143.6 (1) |
C5—N1—C2—C21 | −176.3 (2) | C56—N51—C52—C53 | 56.7 (2) |
C11—N1—C2—C21 | 0.1 (2) | N51—C52—C53—C54 | −53.0 (2) |
N1—C2—N3—C4 | 0.9 (2) | C52—C53—C54—C55 | 53.8 (2) |
C21—C2—N3—C4 | 178.1 (2) | C53—C54—C55—C56 | −55.9 (2) |
C2—N3—C4—C5 | −2.6 (2) | C5—N51—C56—C55 | 142.4 (1) |
C2—N3—C4—N4 | 169.2 (1) | C52—N51—C56—C55 | −57.8 (2) |
N3—C4—N4—O42 | −165.5 (1) | C54—C55—C56—N51 | 56.3 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13···N3i | 0.97 (2) | 2.45 (2) | 3.424 (2) | 180 (1) |
C54—H54B···Cl14ii | 0.98 (2) | 3.06 (2) | 3.705 (2) | 125 (1) |
C55—H55B···Cl14ii | 0.97 (2) | 2.95 (1) | 3.564 (2) | 122 (1) |
Symmetry codes: (i) x+1, y, z; (ii) −x+3/2, −y, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C15H17ClN4O2 |
Mr | 320.78 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 90 |
a, b, c (Å) | 8.5841 (12), 9.0352 (12), 18.738 (2) |
V (Å3) | 1453.3 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.28 |
Crystal size (mm) | 0.4 × 0.15 × 0.1 |
Data collection | |
Diffractometer | Kuma KM4 CCD four-circle diffractometer |
Absorption correction | Multi-scan (SORTAV; Blessing, 1989) |
Tmin, Tmax | 0.958, 0.972 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15516, 4072, 3298 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.031, 0.054, 0.93 |
No. of reflections | 4069 |
No. of parameters | 257 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.25, −0.22 |
Absolute structure | Flack (1983), with how many Friedel pairs? |
Absolute structure parameter | −0.03 (4) |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2002), CrysAlis CCD, CrysAlis RED (Oxford Diffraction, 2002), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), Stereochemical Workstation Operation Manual (Siemens, 1989), SHELXL97.
N1—C2 | 1.383 (2) | N3—C4 | 1.376 (2) |
N1—C5 | 1.391 (2) | N4—O42 | 1.234 (2) |
N1—C11 | 1.438 (2) | N4—O41 | 1.239 (2) |
C2—N3 | 1.301 (2) | C5—N51 | 1.361 (2) |
C2—N1—C5 | 108.1 (1) | O42—N4—C4 | 118.9 (1) |
C2—N1—C11 | 124.7 (1) | O41—N4—C4 | 117.8 (1) |
C5—N1—C11 | 127.1 (1) | C5—N51—C56 | 120.7 (1) |
C2—N3—C4 | 105.0 (1) | C5—N51—C52 | 121.2 (1) |
O42—N4—O41 | 123.2 (1) | C56—N51—C52 | 114.9 (1) |
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13···N3i | 0.97 (2) | 2.45 (2) | 3.424 (2) | 180 (1) |
C54—H54B···Cl14ii | 0.98 (2) | 3.06 (2) | 3.705 (2) | 125 (1) |
C55—H55B···Cl14ii | 0.97 (2) | 2.95 (1) | 3.564 (2) | 122 (1) |
Symmetry codes: (i) x+1, y, z; (ii) −x+3/2, −y, z−1/2. |
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Nitroimidazoles have been intensively investigated as radiosensitizers of hypoxic tumour cells and as veterinary drugs (Smithen & Hardy, 1982). In particular, 4-nitro-5-aminoimidazole derivatives have been relatively widely studied, due to their expected radiosensitizing activity combined with good water solubility (see, for example, Wolska et al., 1993, 1994). More recently, in the crystal structure of 1,2-dimethyl-4-nitro-5-morpholinylimidazole hydrate, the interesting case of centro–noncentro ambiguity was found (Kubicki et al., 2003). Moreover, a number of simple 4-nitroimidazole derivatives have been used for studying different intermolecular interactions (see, for example, Kubicki, 2005, and references therein). The structure of another 4-nitro-5-aminoimidazole, the title compound, (I), is reported here. The ability of 4-nitroimidazoles to undergo nucleophilic substitution has been widely investigated (see, for example, M\,akosza, 1992) and provides a convenient way of modifying azole derivatives. Some amino derivatives have also been synthesized in this way (M\,akosza & Białecki, 1998; Suwiński & Świerczek, 1996).
Fig. 1 shows a displacement ellipsoid representation of (I). The benzene and imidazole rings are almost perfectly planar, the maximum deviations from the least-squares planes being not larger than 0.015 (1) Å. The dihedral angle between the mean planes of these rings is 59.82 (5)°. The nitro group is also significantly twisted out of the imidazole plane, the dihedral angle between the appropriate planes being 14.7 (2)°. This value is larger than in similar compounds and is probably caused by the presence of the bulky substituent at position 5. The C—N—O angles are asymmetric, and this asymmetry is typical of 5-substituted 4-nitroimidazole derivatives (Kubicki, 2004a). The C4—N4—O41 angle (cis with respect to imidazole ring atom N3) is smaller than the angle trans to N3 (C4—N4—O42) by 1.1°. For 5-H derivatives, this asymmetry in C—N—O angles is also observed, but in reverse: the cis angle is larger than the trans one (Kubicki, 2004b).
The molecular geometry of (I) is quite typical. In this type of compound, there is an interesting correlation between the C5—N51 bond length and the sum of the bond angles around N51: the longer the bond, the larger is the pyramidalization of the N atom, i.e. the smaller the sum of the bond angles. For 16 fragments of 5-(cyclic)amino imidazoles found in the CSD (November 2004 version, February 2005 updates; Allen, 2002), the correlation coefficient is 0.98 (Fig. 2), and the data for (I) fit perfectly into this relation. It might also be noted that there is no such correlation between the C5—N51 bond length and the angles around atom C5.
The piperidine ring is in a chair conformation. The asymmetry parameters (Duax & Norton, 1975) show only minor distortions from the ideal C3d symmetry (maximum value of the ΔC2 parameter is 3.83°, and of ΔCs −3.15°).
In the crystal structure of (I), there are infinite chains of molecules extending along the [100] direction, created by C—H···N3 hydrogen bonds. Using graph-set notation (Etter et al., 1990; Bernstein et al., 1995), this motif can be described as a C(7) chain. Neighbouring chains are connected by weak three-centred C—H···Cl hydrogen bonds {C(12)[R21(5)] chains along the [001] direction}. These two kinds of weak interactions close larger rings of molecules of motif R44(30) (Fig. 3). The geometric details of these interactions are given in Table 2. Interestingly, in this case no other specific interatomic interactions (e.g. π–π stacking or halogen bonds) take part in the creation of the supramolecular structure, even though these interactions could compete succesfully with weak hydrogen bonding.