organic compounds
Ethyl 2-(4-bromophenyl)-1-sec-butyl-1H-benzimidazole-5-carboxylate
aSchool of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and bKulliyyah of Science, International Islamic University Malaysia, Bandar Indera Mahkota, 25200 Kuantan, Pahang, Malaysia
*Correspondence e-mail: aisyah@usm.my
In the title compound, C20H21BrN2O2, the bromophenyl ring is twisted by 40.13 (8)° from the benzimidazole mean plane and the Br atom deviates by 0.753 (1) Å from that plane. The sec-butyl group is disordered over two conformations in a 0.898 (5):0.102 (5) ratio. In the crystal, molecules related by translation along [10] are linked into chains via weak C—H⋯Br hydrogen bonds.
Related literature
For the synthesis and closely related structures, see: Arumugam et al. (2010, 2011); Navarrete-Vazquez et al. (2006). For therapeutic properties of benzimidazole derivatives, see: Vitale et al. (2008, 2009); Arienti et al. (2005). For standard bond lengths, see: Allen et al. (1987). For the low-temperature device used in the data collection, see: Cosier & Glazer (1986).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2009); cell SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009).
Supporting information
https://doi.org/10.1107/S1600536811048999/cv5201sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811048999/cv5201Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536811048999/cv5201Isup3.cml
Preparation of the title compound was performed using the previous procedure described by Arumugam et al. (2010) and Arumugam et al. (2011). Recrystallization of the crude product from ethyl acetate furnished colourless crystals suitable for X-ray analysis.
X-ray data were collected at low temperature (Cosier & Glazer, 1986). All H atoms were positioned geometrically and refined using riding model with C—H = 0.95–1.00Å and Uiso(H)=1.2 or 1.5Ueq(C). A sec- butyl group (C17/C18/C19/C20) is disordered over two conformations in a ratio 0.898 (5):0.102 (5). A minor component of disorder (C17B/C18B/C19B/C20B) was refined isotropically. A rotating group model was applied for methyl group.
Accelerated condensation of substituted phenylenediamines with adducts of
under microwave conditions provides access into 2-arylbenzimidazoles (Navarrete-Vazquez et al., 2006; Arumugam et al., 2010; 2011). These 2-substituted benzimidazoles have recently gained attention due to their antiviral and antiproliferative activities (Vitale et al., 2008; 2009). Not only that, a series of novel 2-arylbenzimidazoles was found to exhibit highly on chk2 kinase, which helps to control DNA damage and could prove useful as an adjuvant to radiotherapy (Arienti et al., 2005). In continuation with our work in 2-arylbenzimidazoles (Arumugam et al., 2010; 2011), we present herein the X-ray determination of the title compound.The title compound, (Fig. 1), is similar to those previously reported, ethyl 1-sec-butyl-2-(4-chlorophenyl)-1H-benzimidazole-5- carboxylate (Arumugam et al., 2010) and ethyl 1-sec-butyl-2- (4-fluorophenyl)-1H-benzimidazole-5-carboxylate (Arumugam et al., 2011), except the bromine atom is attached at the para position of benzene ring.The bond lengths and angles are in normal ranges (Allen et al., 1987) and in agreement with those reported by Arumugam et al. (2010) and Arumugam et al. (2011). The sec-butyl group (C17/C18/C19/C20) is disordered over two conformations in a ratio 0.898 (5):0.102 (5). The bromophenyl ring (C1—C6/Br1) is twisted at 40.13 (8)° from the benzimidazole mean plane (C8/C9/C10/C11/C12/C13/N1/N2/C7) and Br atom deviates at 0.753 (1)Å from that plane.
In the
(Fig. 2), the molecules related by translation along [-110] are linked into chains via weak intermolecular C16—H16A···Br1 hydrogen bonds (Table 1).For the synthesis and closely related structures, see: Arumugam et al. (2010, 2011); Navarrete-Vazquez et al. (2006). For therapeutic properties of benzimidazole derivatives, see: Vitale et al. (2008, 2009); Arienti et al. (2005). For standard bond lengths, see: Allen et al. (1987). For the low-temperature device used in the data collection, see: Cosier & Glazer (1986).
Data collection: APEX2 (Bruker, 2009); cell
SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).C20H21BrN2O2 | F(000) = 824 |
Mr = 401.30 | Dx = 1.460 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 15956 reflections |
a = 10.5187 (2) Å | θ = 1.9–25.0° |
b = 12.7525 (2) Å | µ = 2.27 mm−1 |
c = 13.7444 (2) Å | T = 100 K |
β = 98.101 (1)° | Block, colourless |
V = 1825.27 (5) Å3 | 0.39 × 0.39 × 0.20 mm |
Z = 4 |
Bruker SMART APEXII CCD area-detector diffractometer | 3221 independent reflections |
Radiation source: fine-focus sealed tube | 3073 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.024 |
Detector resolution: 83.66 pixels mm-1 | θmax = 25.0°, θmin = 1.9° |
φ and ω scans | h = −12→12 |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | k = −15→15 |
Tmin = 0.471, Tmax = 0.666 | l = −16→16 |
24453 measured reflections |
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)] = 0.022 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.056 | H-atom parameters constrained |
S = 1.08 | w = 1/[σ2(Fo2) + (0.0253P)2 + 1.2079P] where P = (Fo2 + 2Fc2)/3 |
3221 reflections | (Δ/σ)max < 0.001 |
248 parameters | Δρmax = 0.30 e Å−3 |
12 restraints | Δρmin = −0.24 e Å−3 |
C20H21BrN2O2 | V = 1825.27 (5) Å3 |
Mr = 401.30 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 10.5187 (2) Å | µ = 2.27 mm−1 |
b = 12.7525 (2) Å | T = 100 K |
c = 13.7444 (2) Å | 0.39 × 0.39 × 0.20 mm |
β = 98.101 (1)° |
Bruker SMART APEXII CCD area-detector diffractometer | 3221 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | 3073 reflections with I > 2σ(I) |
Tmin = 0.471, Tmax = 0.666 | Rint = 0.024 |
24453 measured reflections |
R[F2 > 2σ(F2)] = 0.022 | 12 restraints |
wR(F2) = 0.056 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.30 e Å−3 |
3221 reflections | Δρmin = −0.24 e Å−3 |
248 parameters |
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open=flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. |
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 | Occ. (<1) | |
Br1 | 1.437653 (17) | −0.132336 (14) | 0.052952 (13) | 0.02810 (7) | |
O1 | 0.49686 (12) | 0.48183 (10) | 0.16898 (9) | 0.0271 (3) | |
O2 | 0.66303 (12) | 0.53232 (9) | 0.09400 (9) | 0.0257 (3) | |
N1 | 0.97007 (13) | 0.22220 (11) | 0.12388 (10) | 0.0189 (3) | |
N2 | 0.87714 (13) | 0.08790 (11) | 0.19561 (10) | 0.0196 (3) | |
C1 | 1.21317 (17) | 0.10333 (14) | 0.14588 (12) | 0.0216 (4) | |
H1A | 1.2249 | 0.1737 | 0.1680 | 0.026* | |
C2 | 1.31726 (17) | 0.04696 (14) | 0.12213 (12) | 0.0224 (4) | |
H2A | 1.4001 | 0.0780 | 0.1278 | 0.027* | |
C3 | 1.29818 (16) | −0.05549 (14) | 0.08999 (12) | 0.0212 (4) | |
C4 | 1.17921 (17) | −0.10309 (14) | 0.08218 (12) | 0.0222 (4) | |
H4A | 1.1684 | −0.1738 | 0.0608 | 0.027* | |
C5 | 1.07572 (17) | −0.04590 (13) | 0.10604 (12) | 0.0211 (4) | |
H5A | 0.9933 | −0.0777 | 0.1008 | 0.025* | |
C6 | 1.09155 (16) | 0.05814 (13) | 0.13774 (11) | 0.0190 (3) | |
C7 | 0.98140 (16) | 0.12428 (13) | 0.15413 (12) | 0.0187 (3) | |
C8 | 0.79159 (16) | 0.17113 (13) | 0.19091 (12) | 0.0191 (3) | |
C9 | 0.67050 (16) | 0.18299 (14) | 0.22094 (12) | 0.0212 (4) | |
H9A | 0.6311 | 0.1276 | 0.2520 | 0.025* | |
C10 | 0.61127 (16) | 0.27893 (14) | 0.20317 (12) | 0.0204 (3) | |
H10A | 0.5289 | 0.2896 | 0.2223 | 0.024* | |
C11 | 0.66927 (16) | 0.36167 (13) | 0.15738 (12) | 0.0189 (3) | |
C12 | 0.78936 (16) | 0.34958 (13) | 0.12819 (12) | 0.0185 (3) | |
H12A | 0.8283 | 0.4051 | 0.0970 | 0.022* | |
C13 | 0.85105 (16) | 0.25334 (13) | 0.14619 (12) | 0.0178 (3) | |
C14 | 0.59928 (16) | 0.46288 (13) | 0.14229 (12) | 0.0204 (4) | |
C15 | 0.60340 (19) | 0.63412 (14) | 0.07495 (14) | 0.0282 (4) | |
H15A | 0.6069 | 0.6746 | 0.1367 | 0.034* | |
H15B | 0.5124 | 0.6260 | 0.0457 | 0.034* | |
C16 | 0.6779 (2) | 0.68923 (16) | 0.00444 (17) | 0.0381 (5) | |
H16A | 0.6410 | 0.7589 | −0.0107 | 0.057* | |
H16B | 0.6736 | 0.6482 | −0.0563 | 0.057* | |
H16C | 0.7677 | 0.6965 | 0.0343 | 0.057* | |
C17A | 0.8740 (2) | −0.00625 (16) | 0.25876 (16) | 0.0213 (5) | 0.898 (5) |
H17A | 0.9573 | −0.0439 | 0.2583 | 0.026* | 0.898 (5) |
C18A | 0.8681 (3) | 0.0262 (2) | 0.36369 (17) | 0.0287 (6) | 0.898 (5) |
H18A | 0.8781 | −0.0366 | 0.4065 | 0.034* | 0.898 (5) |
H18B | 0.7829 | 0.0574 | 0.3683 | 0.034* | 0.898 (5) |
C19A | 0.9724 (2) | 0.10532 (19) | 0.39981 (15) | 0.0306 (6) | 0.898 (5) |
H19A | 0.9687 | 0.1218 | 0.4690 | 0.046* | 0.898 (5) |
H19B | 0.9591 | 0.1695 | 0.3605 | 0.046* | 0.898 (5) |
H19C | 1.0567 | 0.0756 | 0.3932 | 0.046* | 0.898 (5) |
C20A | 0.7673 (2) | −0.08225 (17) | 0.21800 (19) | 0.0308 (6) | 0.898 (5) |
H20A | 0.7736 | −0.0974 | 0.1489 | 0.046* | 0.898 (5) |
H20B | 0.6836 | −0.0505 | 0.2230 | 0.046* | 0.898 (5) |
H20C | 0.7762 | −0.1475 | 0.2559 | 0.046* | 0.898 (5) |
C17B | 0.9167 (17) | 0.0113 (12) | 0.2755 (10) | 0.065 (13)* | 0.102 (5) |
H17B | 0.9988 | −0.0258 | 0.2688 | 0.077* | 0.102 (5) |
C18B | 0.9091 (19) | 0.0503 (16) | 0.3795 (13) | 0.017 (5)* | 0.102 (5) |
H18C | 0.9461 | −0.0025 | 0.4271 | 0.025* | 0.102 (5) |
H18D | 0.8191 | 0.0623 | 0.3873 | 0.025* | 0.102 (5) |
H18E | 0.9572 | 0.1160 | 0.3909 | 0.025* | 0.102 (5) |
C19B | 0.8038 (18) | −0.0613 (15) | 0.2757 (13) | 0.032 (5)* | 0.102 (5) |
H19D | 0.7256 | −0.0199 | 0.2814 | 0.038* | 0.102 (5) |
H19E | 0.8194 | −0.1090 | 0.3329 | 0.038* | 0.102 (5) |
C20B | 0.784 (2) | −0.1251 (15) | 0.1810 (12) | 0.029 (5)* | 0.102 (5) |
H20D | 0.7084 | −0.1703 | 0.1806 | 0.043* | 0.102 (5) |
H20E | 0.8599 | −0.1685 | 0.1771 | 0.043* | 0.102 (5) |
H20F | 0.7704 | −0.0776 | 0.1245 | 0.043* | 0.102 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.02917 (11) | 0.02848 (11) | 0.02913 (11) | 0.01432 (7) | 0.01271 (8) | 0.00389 (7) |
O1 | 0.0221 (6) | 0.0268 (7) | 0.0341 (7) | 0.0081 (5) | 0.0097 (5) | 0.0009 (5) |
O2 | 0.0261 (7) | 0.0199 (6) | 0.0332 (7) | 0.0098 (5) | 0.0111 (5) | 0.0060 (5) |
N1 | 0.0185 (7) | 0.0185 (7) | 0.0205 (7) | 0.0036 (6) | 0.0059 (6) | 0.0023 (6) |
N2 | 0.0205 (7) | 0.0177 (7) | 0.0221 (7) | 0.0038 (6) | 0.0079 (6) | 0.0056 (6) |
C1 | 0.0252 (9) | 0.0180 (8) | 0.0225 (8) | 0.0037 (7) | 0.0061 (7) | 0.0018 (7) |
C2 | 0.0200 (8) | 0.0245 (9) | 0.0235 (9) | 0.0033 (7) | 0.0056 (7) | 0.0042 (7) |
C3 | 0.0230 (9) | 0.0240 (9) | 0.0178 (8) | 0.0111 (7) | 0.0073 (7) | 0.0044 (7) |
C4 | 0.0292 (9) | 0.0183 (8) | 0.0193 (8) | 0.0050 (7) | 0.0044 (7) | 0.0015 (7) |
C5 | 0.0219 (9) | 0.0207 (8) | 0.0208 (8) | 0.0020 (7) | 0.0038 (7) | 0.0034 (7) |
C6 | 0.0210 (8) | 0.0207 (8) | 0.0163 (8) | 0.0050 (7) | 0.0060 (6) | 0.0054 (6) |
C7 | 0.0190 (8) | 0.0199 (9) | 0.0177 (8) | 0.0024 (7) | 0.0045 (6) | 0.0017 (6) |
C8 | 0.0202 (8) | 0.0193 (8) | 0.0181 (8) | 0.0032 (7) | 0.0039 (6) | 0.0017 (6) |
C9 | 0.0211 (9) | 0.0226 (9) | 0.0212 (8) | 0.0008 (7) | 0.0072 (7) | 0.0030 (7) |
C10 | 0.0172 (8) | 0.0264 (9) | 0.0184 (8) | 0.0031 (7) | 0.0054 (6) | −0.0002 (7) |
C11 | 0.0204 (8) | 0.0198 (8) | 0.0162 (8) | 0.0033 (7) | 0.0017 (6) | −0.0015 (6) |
C12 | 0.0200 (8) | 0.0178 (8) | 0.0182 (8) | 0.0013 (6) | 0.0041 (6) | 0.0008 (6) |
C13 | 0.0178 (8) | 0.0196 (8) | 0.0164 (8) | 0.0021 (7) | 0.0033 (6) | 0.0002 (6) |
C14 | 0.0207 (9) | 0.0225 (9) | 0.0178 (8) | 0.0037 (7) | 0.0018 (7) | −0.0018 (7) |
C15 | 0.0311 (10) | 0.0209 (9) | 0.0341 (10) | 0.0121 (7) | 0.0099 (8) | 0.0054 (7) |
C16 | 0.0394 (12) | 0.0276 (11) | 0.0508 (13) | 0.0134 (9) | 0.0183 (10) | 0.0105 (9) |
C17A | 0.0196 (12) | 0.0163 (10) | 0.0300 (11) | 0.0046 (9) | 0.0106 (9) | 0.0119 (8) |
C18A | 0.0251 (13) | 0.0367 (14) | 0.0253 (11) | 0.0060 (11) | 0.0067 (10) | 0.0112 (10) |
C19A | 0.0321 (12) | 0.0402 (13) | 0.0197 (10) | 0.0122 (10) | 0.0039 (8) | 0.0018 (9) |
C20A | 0.0260 (11) | 0.0210 (11) | 0.0469 (15) | −0.0032 (9) | 0.0106 (10) | 0.0020 (11) |
Br1—C3 | 1.8927 (16) | C15—C16 | 1.504 (3) |
O1—C14 | 1.210 (2) | C15—H15A | 0.9900 |
O2—C14 | 1.342 (2) | C15—H15B | 0.9900 |
O2—C15 | 1.450 (2) | C16—H16A | 0.9800 |
N1—C7 | 1.316 (2) | C16—H16B | 0.9800 |
N1—C13 | 1.388 (2) | C16—H16C | 0.9800 |
N2—C7 | 1.385 (2) | C17A—C18A | 1.510 (3) |
N2—C8 | 1.387 (2) | C17A—C20A | 1.528 (4) |
N2—C17B | 1.484 (5) | C17A—H17A | 1.0000 |
N2—C17A | 1.485 (2) | C18A—C19A | 1.522 (4) |
C1—C2 | 1.387 (2) | C18A—H18A | 0.9900 |
C1—C6 | 1.393 (2) | C18A—H18B | 0.9900 |
C1—H1A | 0.9500 | C19A—H19A | 0.9800 |
C2—C3 | 1.385 (3) | C19A—H19B | 0.9800 |
C2—H2A | 0.9500 | C19A—H19C | 0.9800 |
C3—C4 | 1.381 (3) | C20A—H20A | 0.9800 |
C4—C5 | 1.387 (2) | C20A—H20B | 0.9800 |
C4—H4A | 0.9500 | C20A—H20C | 0.9800 |
C5—C6 | 1.399 (2) | C17B—C19B | 1.507 (6) |
C5—H5A | 0.9500 | C17B—C18B | 1.526 (6) |
C6—C7 | 1.476 (2) | C17B—H17B | 1.0000 |
C8—C9 | 1.401 (2) | C18B—H18C | 0.9800 |
C8—C13 | 1.406 (2) | C18B—H18D | 0.9800 |
C9—C10 | 1.379 (2) | C18B—H18E | 0.9800 |
C9—H9A | 0.9500 | C19B—C20B | 1.524 (6) |
C10—C11 | 1.411 (2) | C19B—H19D | 0.9900 |
C10—H10A | 0.9500 | C19B—H19E | 0.9900 |
C11—C12 | 1.387 (2) | C20B—H20D | 0.9800 |
C11—C14 | 1.486 (2) | C20B—H20E | 0.9800 |
C12—C13 | 1.394 (2) | C20B—H20F | 0.9800 |
C12—H12A | 0.9500 | ||
C14—O2—C15 | 116.53 (13) | O2—C14—C11 | 111.71 (14) |
C7—N1—C13 | 104.23 (14) | O2—C15—C16 | 106.46 (14) |
C7—N2—C8 | 105.69 (13) | O2—C15—H15A | 110.4 |
C7—N2—C17B | 111.6 (7) | C16—C15—H15A | 110.4 |
C8—N2—C17B | 130.6 (7) | O2—C15—H15B | 110.4 |
C7—N2—C17A | 126.56 (15) | C16—C15—H15B | 110.4 |
C8—N2—C17A | 125.33 (14) | H15A—C15—H15B | 108.6 |
C17B—N2—C17A | 20.4 (7) | C15—C16—H16A | 109.5 |
C2—C1—C6 | 120.87 (16) | C15—C16—H16B | 109.5 |
C2—C1—H1A | 119.6 | H16A—C16—H16B | 109.5 |
C6—C1—H1A | 119.6 | C15—C16—H16C | 109.5 |
C3—C2—C1 | 118.72 (16) | H16A—C16—H16C | 109.5 |
C3—C2—H2A | 120.6 | H16B—C16—H16C | 109.5 |
C1—C2—H2A | 120.6 | N2—C17A—C18A | 110.12 (18) |
C4—C3—C2 | 121.90 (16) | N2—C17A—C20A | 111.97 (19) |
C4—C3—Br1 | 118.66 (13) | C18A—C17A—C20A | 113.38 (19) |
C2—C3—Br1 | 119.43 (13) | N2—C17A—H17A | 107.0 |
C3—C4—C5 | 118.88 (16) | C18A—C17A—H17A | 107.0 |
C3—C4—H4A | 120.6 | C20A—C17A—H17A | 107.0 |
C5—C4—H4A | 120.6 | C17A—C18A—C19A | 111.61 (19) |
C4—C5—C6 | 120.61 (16) | C17A—C18A—H18A | 109.3 |
C4—C5—H5A | 119.7 | C19A—C18A—H18A | 109.3 |
C6—C5—H5A | 119.7 | C17A—C18A—H18B | 109.3 |
C1—C6—C5 | 119.01 (15) | C19A—C18A—H18B | 109.3 |
C1—C6—C7 | 118.89 (15) | H18A—C18A—H18B | 108.0 |
C5—C6—C7 | 121.87 (15) | N2—C17B—C19B | 105.4 (13) |
N1—C7—N2 | 113.96 (14) | N2—C17B—C18B | 115.6 (14) |
N1—C7—C6 | 122.14 (15) | C19B—C17B—C18B | 93.0 (3) |
N2—C7—C6 | 123.74 (14) | N2—C17B—H17B | 113.6 |
N2—C8—C9 | 132.80 (16) | C19B—C17B—H17B | 113.6 |
N2—C8—C13 | 105.39 (14) | C18B—C17B—H17B | 113.6 |
C9—C8—C13 | 121.81 (15) | C17B—C18B—H18C | 109.5 |
C10—C9—C8 | 116.76 (15) | C17B—C18B—H18D | 109.5 |
C10—C9—H9A | 121.6 | H18C—C18B—H18D | 109.5 |
C8—C9—H9A | 121.6 | C17B—C18B—H18E | 109.5 |
C9—C10—C11 | 121.99 (15) | H18C—C18B—H18E | 109.5 |
C9—C10—H10A | 119.0 | H18D—C18B—H18E | 109.5 |
C11—C10—H10A | 119.0 | C17B—C19B—C20B | 109.9 (15) |
C12—C11—C10 | 120.98 (15) | C17B—C19B—H19D | 109.7 |
C12—C11—C14 | 120.65 (15) | C20B—C19B—H19D | 109.7 |
C10—C11—C14 | 118.37 (15) | C17B—C19B—H19E | 109.7 |
C11—C12—C13 | 117.83 (15) | C20B—C19B—H19E | 109.7 |
C11—C12—H12A | 121.1 | H19D—C19B—H19E | 108.2 |
C13—C12—H12A | 121.1 | C19B—C20B—H20D | 109.5 |
N1—C13—C12 | 128.63 (15) | C19B—C20B—H20E | 109.5 |
N1—C13—C8 | 110.73 (14) | H20D—C20B—H20E | 109.5 |
C12—C13—C8 | 120.63 (15) | C19B—C20B—H20F | 109.5 |
O1—C14—O2 | 123.13 (15) | H20D—C20B—H20F | 109.5 |
O1—C14—C11 | 125.15 (16) | H20E—C20B—H20F | 109.5 |
C6—C1—C2—C3 | 0.0 (3) | C10—C11—C12—C13 | −0.4 (2) |
C1—C2—C3—C4 | −0.8 (3) | C14—C11—C12—C13 | 178.76 (15) |
C1—C2—C3—Br1 | 177.88 (12) | C7—N1—C13—C12 | −178.63 (17) |
C2—C3—C4—C5 | 0.9 (3) | C7—N1—C13—C8 | 0.12 (18) |
Br1—C3—C4—C5 | −177.81 (12) | C11—C12—C13—N1 | 179.76 (16) |
C3—C4—C5—C6 | −0.2 (2) | C11—C12—C13—C8 | 1.1 (2) |
C2—C1—C6—C5 | 0.6 (2) | N2—C8—C13—N1 | −0.08 (18) |
C2—C1—C6—C7 | −173.87 (15) | C9—C8—C13—N1 | 179.70 (15) |
C4—C5—C6—C1 | −0.6 (2) | N2—C8—C13—C12 | 178.78 (15) |
C4—C5—C6—C7 | 173.78 (15) | C9—C8—C13—C12 | −1.4 (3) |
C13—N1—C7—N2 | −0.12 (19) | C15—O2—C14—O1 | 0.4 (2) |
C13—N1—C7—C6 | 175.47 (15) | C15—O2—C14—C11 | 179.89 (14) |
C8—N2—C7—N1 | 0.07 (19) | C12—C11—C14—O1 | −176.80 (16) |
C17B—N2—C7—N1 | −146.9 (8) | C10—C11—C14—O1 | 2.4 (3) |
C17A—N2—C7—N1 | −162.89 (18) | C12—C11—C14—O2 | 3.7 (2) |
C8—N2—C7—C6 | −175.44 (15) | C10—C11—C14—O2 | −177.09 (14) |
C17B—N2—C7—C6 | 37.6 (8) | C14—O2—C15—C16 | −169.26 (16) |
C17A—N2—C7—C6 | 21.6 (3) | C7—N2—C17A—C18A | 108.4 (2) |
C1—C6—C7—N1 | 38.2 (2) | C8—N2—C17A—C18A | −51.4 (3) |
C5—C6—C7—N1 | −136.19 (17) | C17B—N2—C17A—C18A | 61 (2) |
C1—C6—C7—N2 | −146.68 (16) | C7—N2—C17A—C20A | −124.5 (2) |
C5—C6—C7—N2 | 39.0 (2) | C8—N2—C17A—C20A | 75.7 (2) |
C7—N2—C8—C9 | −179.74 (18) | C17B—N2—C17A—C20A | −172 (2) |
C17B—N2—C8—C9 | −41.6 (10) | N2—C17A—C18A—C19A | −51.2 (2) |
C17A—N2—C8—C9 | −16.5 (3) | C20A—C17A—C18A—C19A | −177.58 (17) |
C7—N2—C8—C13 | 0.01 (17) | C7—N2—C17B—C19B | −150.3 (8) |
C17B—N2—C8—C13 | 138.2 (10) | C8—N2—C17B—C19B | 73.4 (14) |
C17A—N2—C8—C13 | 163.24 (19) | C17A—N2—C17B—C19B | −9.8 (15) |
N2—C8—C9—C10 | −179.33 (17) | C7—N2—C17B—C18B | 108.5 (9) |
C13—C8—C9—C10 | 1.0 (2) | C8—N2—C17B—C18B | −27.8 (16) |
C8—C9—C10—C11 | −0.2 (2) | C17A—N2—C17B—C18B | −111 (2) |
C9—C10—C11—C12 | 0.0 (3) | N2—C17B—C19B—C20B | 66.5 (18) |
C9—C10—C11—C14 | −179.21 (15) | C18B—C17B—C19B—C20B | −175.9 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
C16—H16A···Br1i | 0.98 | 2.79 | 3.533 (2) | 133 |
Symmetry code: (i) x−1, y+1, z. |
Experimental details
Crystal data | |
Chemical formula | C20H21BrN2O2 |
Mr | 401.30 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 100 |
a, b, c (Å) | 10.5187 (2), 12.7525 (2), 13.7444 (2) |
β (°) | 98.101 (1) |
V (Å3) | 1825.27 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.27 |
Crystal size (mm) | 0.39 × 0.39 × 0.20 |
Data collection | |
Diffractometer | Bruker SMART APEXII CCD area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 2009) |
Tmin, Tmax | 0.471, 0.666 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 24453, 3221, 3073 |
Rint | 0.024 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.022, 0.056, 1.08 |
No. of reflections | 3221 |
No. of parameters | 248 |
No. of restraints | 12 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.30, −0.24 |
Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
C16—H16A···Br1i | 0.98 | 2.79 | 3.533 (2) | 133 |
Symmetry code: (i) x−1, y+1, z. |
Acknowledgements
NA, SAH and ASAR acknowledge the Malaysia Ministry of Science, Technology and Innovations (MOSTI) for funding the synthetic chemistry work under the R&D initiative grant No. 09-05-lfn-meb-004 and 304/PFARMASI/650544. NA thanks Universiti Sains Malaysia for the award of a postdoctoral fellowship.
References
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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.
Accelerated condensation of substituted phenylenediamines with adducts of aldehydes under microwave conditions provides access into 2-arylbenzimidazoles (Navarrete-Vazquez et al., 2006; Arumugam et al., 2010; 2011). These 2-substituted benzimidazoles have recently gained attention due to their antiviral and antiproliferative activities (Vitale et al., 2008; 2009). Not only that, a series of novel 2-arylbenzimidazoles was found to exhibit highly selective inhibition on chk2 kinase, which helps to control DNA damage and could prove useful as an adjuvant to radiotherapy (Arienti et al., 2005). In continuation with our work in 2-arylbenzimidazoles (Arumugam et al., 2010; 2011), we present herein the X-ray crystal structure determination of the title compound.
The title compound, (Fig. 1), is similar to those previously reported, ethyl 1-sec-butyl-2-(4-chlorophenyl)-1H-benzimidazole-5- carboxylate (Arumugam et al., 2010) and ethyl 1-sec-butyl-2- (4-fluorophenyl)-1H-benzimidazole-5-carboxylate (Arumugam et al., 2011), except the bromine atom is attached at the para position of benzene ring.The bond lengths and angles are in normal ranges (Allen et al., 1987) and in agreement with those reported by Arumugam et al. (2010) and Arumugam et al. (2011). The sec-butyl group (C17/C18/C19/C20) is disordered over two conformations in a ratio 0.898 (5):0.102 (5). The bromophenyl ring (C1—C6/Br1) is twisted at 40.13 (8)° from the benzimidazole mean plane (C8/C9/C10/C11/C12/C13/N1/N2/C7) and Br atom deviates at 0.753 (1)Å from that plane.
In the crystal structure (Fig. 2), the molecules related by translation along [-110] are linked into chains via weak intermolecular C16—H16A···Br1 hydrogen bonds (Table 1).