organic compounds
3-[2-(2-Amino-1H-benzo[d]imidazol-1-yl)ethyl]-1,3-oxazolidin-2-one
aLaboratory of Genetic, Endocrinology and Biotechnology–Faculty of Sciences, Ibn Tofaïl University, Kenitra, Morocco, bNational Center of Energy Sciences and Nuclear Techniques, Rabat, Morocco, and cLaboratoire de Chimie du Solide Appliquée, Faculty of Sciences, Mohammed V University in Rabat, Avenue Ibn Battouta, BP 1014, Rabat, Morocco
*Correspondence e-mail: abouayyadi@yahoo.com
In the title compound, C12H14N4O2, the benzimidazole ring is almost planar (r.m.s. deviation = 0.03 Å), with the fused ring system slightly folded at the shared atoms, with a dihedral angle of 3.4 (1)°. The oxazolidinone ring displays a twisted conformation on the –CH2–CH2– bond and its mean plane makes a dihedral angle of 57.4 (1)° with the benzimidazole ring mean plane. In the crystal, molecules are linked by N—H⋯O and N—H⋯N hydrogen bonds, forming chains propagating along the a-axis direction. The chains are linked by C—H⋯O and C—H⋯N hydrogen bonds, forming a three-dimensional structure, which is reinforced by C—H⋯π interactions.
Keywords: crystal structure; 2-amino-benzimidazole; oxazolidinone; psychotropic; PTC; diethyl-amine; hydrogen bonding.
CCDC reference: 1519450
Structure description
Molecules containing an heterocycle, include compounds with organic, chemical and many pharmacological interests (Komeilizadeh, 2006). Two-thirds of organic compounds, known in the literature, are heterocyclic (Brandi et al., 2003; Ansar et al., 2009). Benzimidazole and oxazoline derivatives have attracted considerable interest because of their important biological activities, such as antidepressant and anxiolytic (Ahabchane et al., 1999, 2000; Alinezhad et al., 2013; Ansari & Lal, 2009). The importance of these pharmacological activities encouraged us to combine both benzimidazole and oxazoline units in one molecule and to assess their toxicity (acute and chronic), and also their psychotropic activity. It involves the synthesis by the transfer phase catalysis (PTC) of a novel benzimidazole derivative from 2-amino-benzimidazole, combined with an oxazolidin-2-one unit.
The title compound, Fig. 1, is build up from an amino-benzimidazole ring linked to an oxazolidin-2-on through an ethylene group. The benzimidazole ring is virtually planar with the maximum deviation from the mean plane being 0.037 (2) Å for atom C7. The oxazoline ring displays a twisted conformation on the C10–C11 bond [puckering amplitude Q2 = 0.107 (3) Å, and the spherical polar angle φ2 = 50.5 (2)°]. The dihedral angle between the mean planes of the benzimidazole system and the oxazoline ring is 57.4 (1)°.
In the crystal, molecules are linked by N—H⋯O and N—H⋯N hydrogen bonds, forming chains propagating along the a-axis direction (Fig. 2 and Table 1). The chains are linked by C—H⋯O and C—H⋯N hydrogen bonds, forming a three-dimensional structure, which is reinforced by C—H⋯π interactions (Fig. 2 and Table 1).
Synthesis and crystallization
Phase transfer catalysis (PTC) is a well established technique, widely used in synthetic chemistry and applied in many industrial processes. Here, we present the principle of the PTC and its benefits for the development of more eco-friendly processes. The alkylation reaction, from the starting product of 2-amino-benzimidazole, was carried out under the same reaction conditions, to form an oxazolidin-2-one unit, which was alkylated to the benzimidazole unit.
To the solution of 2-amino-benzimidazole (1.35 g, 9 mmol) and dichloroethyl amine hydrochloride (2.41 g, 13.5 mmol) in dimethylformamide (80 ml) were added potassium carbonate (4.14 g, 30 mmol) and tetra-n-butylammonium bromide (0.10 g, 0.3 mmol). The resulting mixture was refluxed for 4 h, then filtered and the solvent removed. The residue was purified by on silica gel (hexane/AcOEt: 60/40) to afford the title compound (Yield 70%, m.p. 504 K). 1H NMR (dppm): 3.35: SCH2 (2H, t, J = 6.3 Hz); 3.37: NCH2 (4H, m); 4.16: OCH2 (2H, t, J = 6.6 Hz); 7.09–7.12: CH-benzenic (4H, m); 12.54: NH (1H, s).
Refinement
Crystal data, data collection and structure .
details are summarized in Table 2
|
Structural data
CCDC reference: 1519450
https://doi.org/10.1107/S2414314616018952/su4100sup1.cif
contains datablocks I, Global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314616018952/su4100Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2414314616018952/su4100Isup3.cml
Data collection: APEX2 (Bruker, 2009); cell
SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 Farrugia, 2012) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015b), PLATON (Spek, 2009) and publCIF (Westrip, 2010).C12H14N4O2 | Dx = 1.389 Mg m−3 |
Mr = 246.27 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pna21 | Cell parameters from 3320 reflections |
a = 9.0504 (2) Å | θ = 2.7–29.6° |
b = 9.0612 (1) Å | µ = 0.10 mm−1 |
c = 14.3565 (2) Å | T = 296 K |
V = 1177.34 (3) Å3 | Block, colourless |
Z = 4 | 0.44 × 0.34 × 0.26 mm |
F(000) = 520 |
Bruker X8 APEX diffractometer | 3320 independent reflections |
Radiation source: fine-focus sealed tube | 3097 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.034 |
φ and ω scans | θmax = 29.6°, θmin = 2.7° |
Absorption correction: multi-scan (SADABS; Krause et al., 2015) | h = −12→12 |
Tmin = 0.663, Tmax = 0.746 | k = −12→12 |
46121 measured reflections | l = −19→19 |
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)] = 0.035 | H-atom parameters constrained |
wR(F2) = 0.100 | w = 1/[σ2(Fo2) + (0.0582P)2 + 0.1462P] where P = (Fo2 + 2Fc2)/3 |
S = 1.07 | (Δ/σ)max < 0.001 |
3320 reflections | Δρmax = 0.20 e Å−3 |
163 parameters | Δρmin = −0.24 e Å−3 |
1 restraint | Absolute structure: Flack x determined using 1380 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013) |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: −0.3 (3) |
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 | ||
C1 | 0.98692 (19) | 0.55021 (18) | 0.54222 (14) | 0.0305 (3) | |
C2 | 1.1216 (2) | 0.5197 (2) | 0.49961 (18) | 0.0408 (4) | |
H2 | 1.2096 | 0.5567 | 0.5237 | 0.049* | |
C3 | 1.1210 (3) | 0.4324 (2) | 0.42002 (19) | 0.0480 (5) | |
H3 | 1.2102 | 0.4110 | 0.3908 | 0.058* | |
C4 | 0.9909 (3) | 0.3764 (2) | 0.38293 (17) | 0.0479 (5) | |
H4 | 0.9947 | 0.3177 | 0.3298 | 0.057* | |
C5 | 0.8550 (2) | 0.4067 (2) | 0.42404 (15) | 0.0396 (4) | |
H5 | 0.7674 | 0.3698 | 0.3995 | 0.047* | |
C6 | 0.85612 (19) | 0.49410 (19) | 0.50313 (13) | 0.0292 (3) | |
C7 | 0.80874 (18) | 0.63783 (18) | 0.62457 (12) | 0.0276 (3) | |
C8 | 0.58530 (19) | 0.5271 (2) | 0.54381 (13) | 0.0318 (4) | |
H8A | 0.5635 | 0.5317 | 0.4777 | 0.038* | |
H8B | 0.5305 | 0.6055 | 0.5743 | 0.038* | |
C9 | 0.5335 (2) | 0.3792 (2) | 0.58184 (13) | 0.0346 (4) | |
H9A | 0.4274 | 0.3718 | 0.5737 | 0.042* | |
H9B | 0.5788 | 0.3009 | 0.5457 | 0.042* | |
C10 | 0.6839 (4) | 0.2609 (4) | 0.7117 (2) | 0.0633 (8) | |
H10A | 0.7806 | 0.2972 | 0.6936 | 0.076* | |
H10B | 0.6712 | 0.1612 | 0.6884 | 0.076* | |
C11 | 0.6626 (4) | 0.2679 (3) | 0.8156 (2) | 0.0661 (8) | |
H11A | 0.6234 | 0.1753 | 0.8389 | 0.079* | |
H11B | 0.7557 | 0.2879 | 0.8466 | 0.079* | |
C12 | 0.5022 (2) | 0.4301 (2) | 0.74885 (15) | 0.0357 (4) | |
N1 | 0.95466 (16) | 0.63860 (17) | 0.61871 (12) | 0.0322 (3) | |
N2 | 0.74285 (16) | 0.55200 (16) | 0.55759 (10) | 0.0285 (3) | |
N3 | 0.73039 (18) | 0.71167 (19) | 0.69026 (12) | 0.0362 (3) | |
H3A | 0.7756 | 0.7632 | 0.7317 | 0.043* | |
H3B | 0.6355 | 0.7069 | 0.6905 | 0.043* | |
N4 | 0.56840 (19) | 0.35663 (18) | 0.67963 (12) | 0.0337 (3) | |
O1 | 0.5596 (3) | 0.3860 (2) | 0.83151 (12) | 0.0560 (5) | |
O2 | 0.4053 (2) | 0.52092 (19) | 0.74365 (15) | 0.0548 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0284 (8) | 0.0282 (7) | 0.0350 (9) | −0.0007 (6) | 0.0017 (7) | 0.0036 (7) |
C2 | 0.0310 (8) | 0.0388 (9) | 0.0526 (12) | 0.0001 (7) | 0.0087 (9) | 0.0003 (9) |
C3 | 0.0476 (12) | 0.0429 (10) | 0.0534 (13) | 0.0076 (9) | 0.0210 (10) | 0.0027 (10) |
C4 | 0.0621 (14) | 0.0433 (10) | 0.0383 (11) | 0.0036 (10) | 0.0122 (10) | −0.0042 (9) |
C5 | 0.0464 (11) | 0.0388 (9) | 0.0335 (9) | −0.0026 (8) | 0.0000 (8) | −0.0018 (8) |
C6 | 0.0301 (7) | 0.0289 (7) | 0.0286 (8) | −0.0002 (6) | 0.0030 (7) | 0.0041 (6) |
C7 | 0.0263 (7) | 0.0289 (7) | 0.0276 (7) | −0.0008 (6) | −0.0032 (6) | 0.0024 (6) |
C8 | 0.0257 (7) | 0.0387 (8) | 0.0312 (9) | −0.0022 (6) | −0.0056 (7) | 0.0034 (7) |
C9 | 0.0317 (8) | 0.0397 (9) | 0.0325 (9) | −0.0070 (7) | −0.0013 (7) | −0.0038 (7) |
C10 | 0.0683 (17) | 0.0687 (17) | 0.0529 (13) | 0.0356 (14) | −0.0008 (13) | 0.0052 (12) |
C11 | 0.093 (2) | 0.0564 (15) | 0.0491 (14) | 0.0210 (15) | −0.0150 (15) | 0.0098 (12) |
C12 | 0.0363 (9) | 0.0335 (8) | 0.0373 (9) | −0.0036 (7) | 0.0085 (8) | −0.0001 (8) |
N1 | 0.0249 (6) | 0.0339 (7) | 0.0377 (8) | −0.0011 (6) | −0.0009 (6) | −0.0027 (6) |
N2 | 0.0240 (6) | 0.0331 (7) | 0.0282 (7) | −0.0026 (5) | −0.0008 (5) | −0.0002 (5) |
N3 | 0.0268 (7) | 0.0458 (8) | 0.0362 (8) | 0.0023 (6) | −0.0011 (6) | −0.0089 (7) |
N4 | 0.0347 (8) | 0.0340 (7) | 0.0325 (8) | 0.0049 (6) | 0.0030 (6) | 0.0008 (6) |
O1 | 0.0754 (12) | 0.0597 (10) | 0.0330 (7) | 0.0104 (9) | 0.0072 (8) | 0.0016 (7) |
O2 | 0.0462 (8) | 0.0498 (9) | 0.0685 (12) | 0.0139 (7) | 0.0149 (9) | −0.0051 (8) |
C1—N1 | 1.390 (3) | C8—H8A | 0.9700 |
C1—C2 | 1.392 (3) | C8—H8B | 0.9700 |
C1—C6 | 1.405 (2) | C9—N4 | 1.453 (3) |
C2—C3 | 1.390 (4) | C9—H9A | 0.9700 |
C2—H2 | 0.9300 | C9—H9B | 0.9700 |
C3—C4 | 1.388 (4) | C10—N4 | 1.434 (3) |
C3—H3 | 0.9300 | C10—C11 | 1.506 (4) |
C4—C5 | 1.392 (3) | C10—H10A | 0.9700 |
C4—H4 | 0.9300 | C10—H10B | 0.9700 |
C5—C6 | 1.384 (3) | C11—O1 | 1.437 (3) |
C5—H5 | 0.9300 | C11—H11A | 0.9700 |
C6—N2 | 1.392 (2) | C11—H11B | 0.9700 |
C7—N1 | 1.323 (2) | C12—O2 | 1.206 (3) |
C7—N3 | 1.356 (2) | C12—N4 | 1.337 (3) |
C7—N2 | 1.373 (2) | C12—O1 | 1.356 (3) |
C8—N2 | 1.457 (2) | N3—H3A | 0.8600 |
C8—C9 | 1.522 (3) | N3—H3B | 0.8600 |
N1—C1—C2 | 130.21 (18) | N4—C9—H9B | 108.8 |
N1—C1—C6 | 110.30 (15) | C8—C9—H9B | 108.8 |
C2—C1—C6 | 119.38 (18) | H9A—C9—H9B | 107.7 |
C3—C2—C1 | 118.1 (2) | N4—C10—C11 | 101.5 (2) |
C3—C2—H2 | 121.0 | N4—C10—H10A | 111.5 |
C1—C2—H2 | 121.0 | C11—C10—H10A | 111.5 |
C4—C3—C2 | 121.8 (2) | N4—C10—H10B | 111.5 |
C4—C3—H3 | 119.1 | C11—C10—H10B | 111.5 |
C2—C3—H3 | 119.1 | H10A—C10—H10B | 109.3 |
C3—C4—C5 | 121.0 (2) | O1—C11—C10 | 105.8 (2) |
C3—C4—H4 | 119.5 | O1—C11—H11A | 110.6 |
C5—C4—H4 | 119.5 | C10—C11—H11A | 110.6 |
C6—C5—C4 | 117.0 (2) | O1—C11—H11B | 110.6 |
C6—C5—H5 | 121.5 | C10—C11—H11B | 110.6 |
C4—C5—H5 | 121.5 | H11A—C11—H11B | 108.7 |
C5—C6—N2 | 132.14 (17) | O2—C12—N4 | 128.3 (2) |
C5—C6—C1 | 122.73 (17) | O2—C12—O1 | 122.3 (2) |
N2—C6—C1 | 105.05 (16) | N4—C12—O1 | 109.41 (17) |
N1—C7—N3 | 124.29 (17) | C7—N1—C1 | 104.88 (15) |
N1—C7—N2 | 113.07 (16) | C7—N2—C6 | 106.68 (14) |
N3—C7—N2 | 122.63 (15) | C7—N2—C8 | 127.43 (15) |
N2—C8—C9 | 112.90 (15) | C6—N2—C8 | 125.88 (15) |
N2—C8—H8A | 109.0 | C7—N3—H3A | 120.0 |
C9—C8—H8A | 109.0 | C7—N3—H3B | 120.0 |
N2—C8—H8B | 109.0 | H3A—N3—H3B | 120.0 |
C9—C8—H8B | 109.0 | C12—N4—C10 | 112.89 (19) |
H8A—C8—H8B | 107.8 | C12—N4—C9 | 123.40 (17) |
N4—C9—C8 | 113.80 (16) | C10—N4—C9 | 123.59 (19) |
N4—C9—H9A | 108.8 | C12—O1—C11 | 109.20 (18) |
C8—C9—H9A | 108.8 | ||
N1—C1—C2—C3 | −176.61 (19) | N1—C7—N2—C8 | −179.77 (16) |
C6—C1—C2—C3 | −0.8 (3) | N3—C7—N2—C8 | 1.1 (3) |
C1—C2—C3—C4 | 0.1 (3) | C5—C6—N2—C7 | −176.61 (19) |
C2—C3—C4—C5 | 0.5 (4) | C1—C6—N2—C7 | 0.17 (18) |
C3—C4—C5—C6 | −0.2 (3) | C5—C6—N2—C8 | 2.3 (3) |
C4—C5—C6—N2 | 175.75 (19) | C1—C6—N2—C8 | 179.11 (16) |
C4—C5—C6—C1 | −0.6 (3) | C9—C8—N2—C7 | −101.4 (2) |
N1—C1—C6—C5 | 177.68 (17) | C9—C8—N2—C6 | 79.8 (2) |
C2—C1—C6—C5 | 1.1 (3) | O2—C12—N4—C10 | 177.6 (3) |
N1—C1—C6—N2 | 0.51 (19) | O1—C12—N4—C10 | −3.2 (3) |
C2—C1—C6—N2 | −176.04 (17) | O2—C12—N4—C9 | 1.5 (3) |
N2—C8—C9—N4 | 55.4 (2) | O1—C12—N4—C9 | −179.31 (18) |
N4—C10—C11—O1 | −10.9 (4) | C11—C10—N4—C12 | 8.9 (3) |
N3—C7—N1—C1 | −179.78 (16) | C11—C10—N4—C9 | −175.0 (2) |
N2—C7—N1—C1 | 1.1 (2) | C8—C9—N4—C12 | 70.4 (2) |
C2—C1—N1—C7 | 175.1 (2) | C8—C9—N4—C10 | −105.2 (3) |
C6—C1—N1—C7 | −1.0 (2) | O2—C12—O1—C11 | 174.7 (2) |
N1—C7—N2—C6 | −0.9 (2) | N4—C12—O1—C11 | −4.5 (3) |
N3—C7—N2—C6 | −179.95 (16) | C10—C11—O1—C12 | 9.9 (4) |
Cg1 is the centroid of C1–C6 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3A···O2i | 0.86 | 2.29 | 2.994 (2) | 140 |
N3—H3B···N1ii | 0.86 | 2.39 | 3.020 (2) | 131 |
C8—H8A···O1iii | 0.97 | 2.49 | 3.410 (3) | 158 |
C8—H8B···N1ii | 0.97 | 2.50 | 3.425 (2) | 159 |
C9—H9A···Cg1iv | 0.97 | 2.80 | 3.571 (2) | 137 |
C11—H11B···Cg1v | 0.97 | 2.80 | 3.730 (3) | 161 |
Symmetry codes: (i) x+1/2, −y+3/2, z; (ii) x−1/2, −y+3/2, z; (iii) −x+1, −y+1, z−1/2; (iv) x−1/2, −y+1/2, z; (v) −x+3/2, y−1/2, z+1/2. |
Acknowledgements
The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements and the Ibn Tofaïl University, Kenitra, Morocco, for financial support.
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