organic compounds
6-Chloro-1,4-diethylquinoxaline-2,3(1H,4H)-dione
aLaboratoire de Chimie Organique Appliquée, Faculté des Sciences et Techniques, Université Sidi Mohammed Ben Abdellah, Fès, Morocco, bDepartment of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA, and cLaboratoire de Chimie Organique Hétérocyclique, Pôle de Compétences Pharmacochimie, Mohammed V University in Rabat, BP 1014, Avenue Ibn Batouta, Rabat, Morocco
*Correspondence e-mail: alieljanati@gmail.com
In the title compound, C12H13ClN2O2, the terminal C atoms of the ethyl groups deviate from the mean plane of the quinoxaline-2,3(1H,4H)-dione ring (r.m.s. deviation = 0.016 Å) in opposite directions by −1.451 (2) and 1.472 (2) Å. In the crystal, weak C—H⋯O interactions link the molecules into [100] chains and aromatic π–π stacking interactions [shortest centroid–centroid separation = 3.6631 (9) Å] are also observed.
Keywords: quinoxaline; crystal structure; PTC.
CCDC reference: 1562478
Structure description
As a continuation of our studies of substituted quinoxaline derivatives (El Janati et al., 2017), we now report the synthesis and structure of the title compound (Fig. 1) prepared by the condensation reaction of 6-chloroquinoxaline-2,3(1H,4H)-dione with iodoethane.
The terminal C atoms of the ethyl groups deviate from the mean plane of the quinoxaline-2,3(1H,4H)-dione ring (r.m.s. deviation = 0.016 Å) in opposite directions, by −1.451 (2) and 1.472 (2) Å, for C10 and C12, respectively. In the crystal, weak C—H⋯O interactions link the molecules into [100] chains with O2 acting as a double acceptor (Table 1, Fig. 2). Aromatic π–π stacking interactions occur between the chains: Cg2⋯Cg2( − x,y,-z) = 3.6632 (2) Å and Cg1⋯Cg2( − x, − y, − z) = 3.9508 (2) Å, where Cg1 and Cg2 are the centroids of the N1/C1/C2/N2/C3/C8 and C3–C8 rings, respectively.
Synthesis and crystallization
To a solution of 6-chloro-1,4-dihydroquinoxaline-2,3-dione 0.30 g (1.53 mmol) in DMF (20 ml), were added 0.52 g (3.84 mmol) of potassium carbonate and 0.1 mmol of tetra-n-butyl ammonium. After 10 min of stirring, 3.85 mmol of iodoethane was added, then the mixture was allowed to stir at room temperature for 36 h. After filtration, the DMF was evaporated under reduced pressure and the residue obtained was dissolved in dichloromethane. The organic phase was dried over Na2SO4 and then concentrated. The mixture obtained was chromatographed on a silica gel column [eluent: hexane/ethyl acetate (3/1)]. Crystals were obtained when the solvent was allowed to evaporate.
Refinement
Crystal data, data collection and structure .
details are summarized in Table 2Structural data
CCDC reference: 1562478
https://doi.org/10.1107/S2414314617010525/hb4159sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617010525/hb4159Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2414314617010525/hb4159Isup3.cdx
Supporting information file. DOI: https://doi.org/10.1107/S2414314617010525/hb4159Isup4.cml
Data collection: CrysAlis PRO (Rigaku Oxford Diffraction, 2015); cell
CrysAlis PRO (Rigaku Oxford Diffraction, 2015); data reduction: CrysAlis PRO (Rigaku Oxford Diffraction, 2015); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015b); program(s) used to refine structure: SHELXL (Sheldrick, 2015a); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).C12H13ClN2O2 | F(000) = 1056 |
Mr = 252.69 | Dx = 1.397 Mg m−3 |
Monoclinic, I2/a | Cu Kα radiation, λ = 1.54184 Å |
a = 14.6454 (8) Å | Cell parameters from 1748 reflections |
b = 12.0415 (5) Å | θ = 3.5–71.4° |
c = 15.1149 (9) Å | µ = 2.76 mm−1 |
β = 115.621 (7)° | T = 293 K |
V = 2403.5 (3) Å3 | Irregular, orange |
Z = 8 | 0.22 × 0.18 × 0.12 mm |
Rigaku, Oxford diffraction diffractometer | 2291 independent reflections |
Radiation source: fine-focus sealed X-ray tube, Enhance (Cu) X-ray Source | 1944 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.015 |
Detector resolution: 16.0416 pixels mm-1 | θmax = 71.3°, θmin = 4.9° |
ω scans | h = −15→17 |
Absorption correction: multi-scan (CrysAlis PRO; Rigaku Oxford Diffraction, 2015) | k = −14→14 |
Tmin = 0.749, Tmax = 1.000 | l = −16→18 |
4349 measured reflections |
Refinement on F2 | Primary atom site location: dual |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.045 | H-atom parameters constrained |
wR(F2) = 0.128 | w = 1/[σ2(Fo2) + (0.0765P)2 + 0.5895P] where P = (Fo2 + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max < 0.001 |
2291 reflections | Δρmax = 0.23 e Å−3 |
156 parameters | Δρmin = −0.31 e Å−3 |
0 restraints |
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. |
Refinement. All the H atoms were placed in calculated positions and refined using the riding model with C—H bond lengths of 0.93 Å (CH) or 0.97 Å (CH2) or 0.96 Å (CH3). Isotropic displacement parameters for these atoms were set to 1.2 (CH) or 1.5 (CH3) times Ueq of the parent atom. Idealized Me groups were refined as rotating groups. |
x | y | z | Uiso*/Ueq | ||
Cl1 | 0.13648 (4) | 0.04185 (5) | 0.36551 (4) | 0.0703 (2) | |
O1 | 0.45160 (11) | 0.58336 (12) | 0.38236 (13) | 0.0645 (4) | |
O2 | 0.56068 (10) | 0.39761 (13) | 0.40065 (12) | 0.0646 (4) | |
N1 | 0.31793 (10) | 0.48193 (12) | 0.37493 (10) | 0.0429 (3) | |
N2 | 0.42883 (10) | 0.28937 (12) | 0.38566 (10) | 0.0429 (3) | |
C1 | 0.41348 (13) | 0.49391 (16) | 0.38203 (13) | 0.0464 (4) | |
C2 | 0.47412 (13) | 0.38917 (16) | 0.39038 (13) | 0.0465 (4) | |
C3 | 0.33032 (12) | 0.28080 (14) | 0.37896 (10) | 0.0392 (4) | |
C4 | 0.28666 (13) | 0.17761 (15) | 0.37675 (11) | 0.0446 (4) | |
H4 | 0.3225 | 0.1128 | 0.3799 | 0.054* | |
C5 | 0.18971 (14) | 0.17216 (16) | 0.36987 (12) | 0.0484 (4) | |
C6 | 0.13456 (13) | 0.26574 (18) | 0.36620 (12) | 0.0496 (4) | |
H6 | 0.0696 | 0.2601 | 0.3623 | 0.059* | |
C7 | 0.17739 (13) | 0.36817 (16) | 0.36843 (12) | 0.0454 (4) | |
H7 | 0.1408 | 0.4321 | 0.3661 | 0.054* | |
C8 | 0.27497 (12) | 0.37745 (15) | 0.37412 (10) | 0.0392 (4) | |
C9 | 0.25998 (14) | 0.58452 (16) | 0.36690 (15) | 0.0525 (4) | |
H9A | 0.3067 | 0.6458 | 0.3947 | 0.063* | |
H9B | 0.2212 | 0.5762 | 0.4047 | 0.063* | |
C10 | 0.18908 (18) | 0.6114 (2) | 0.26220 (18) | 0.0694 (6) | |
H10A | 0.2268 | 0.6166 | 0.2239 | 0.104* | |
H10B | 0.1561 | 0.6810 | 0.2599 | 0.104* | |
H10C | 0.1392 | 0.5538 | 0.2361 | 0.104* | |
C11 | 0.49092 (14) | 0.18977 (17) | 0.39550 (14) | 0.0514 (4) | |
H11A | 0.5418 | 0.2065 | 0.3725 | 0.062* | |
H11B | 0.4482 | 0.1309 | 0.3547 | 0.062* | |
C12 | 0.54246 (17) | 0.15049 (17) | 0.50063 (16) | 0.0628 (5) | |
H12A | 0.5870 | 0.0899 | 0.5055 | 0.094* | |
H12B | 0.4923 | 0.1262 | 0.5213 | 0.094* | |
H12C | 0.5809 | 0.2104 | 0.5418 | 0.094* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0777 (4) | 0.0587 (3) | 0.0866 (4) | −0.0233 (2) | 0.0469 (3) | −0.0045 (2) |
O1 | 0.0571 (8) | 0.0507 (8) | 0.0965 (11) | −0.0130 (6) | 0.0433 (8) | −0.0084 (7) |
O2 | 0.0429 (7) | 0.0682 (9) | 0.0922 (11) | −0.0037 (6) | 0.0380 (7) | 0.0008 (8) |
N1 | 0.0392 (7) | 0.0452 (8) | 0.0479 (7) | −0.0025 (6) | 0.0221 (6) | −0.0040 (6) |
N2 | 0.0403 (7) | 0.0482 (8) | 0.0447 (7) | −0.0005 (6) | 0.0225 (6) | −0.0036 (6) |
C1 | 0.0422 (8) | 0.0493 (10) | 0.0517 (9) | −0.0068 (7) | 0.0242 (7) | −0.0054 (7) |
C2 | 0.0402 (8) | 0.0550 (10) | 0.0494 (9) | −0.0019 (7) | 0.0241 (7) | −0.0016 (7) |
C3 | 0.0392 (7) | 0.0481 (9) | 0.0334 (7) | −0.0039 (7) | 0.0186 (6) | −0.0033 (6) |
C4 | 0.0506 (9) | 0.0462 (9) | 0.0419 (8) | −0.0024 (7) | 0.0245 (7) | −0.0019 (7) |
C5 | 0.0524 (9) | 0.0551 (10) | 0.0430 (8) | −0.0154 (8) | 0.0256 (7) | −0.0030 (7) |
C6 | 0.0434 (8) | 0.0630 (11) | 0.0488 (9) | −0.0078 (8) | 0.0261 (7) | 0.0008 (8) |
C7 | 0.0405 (8) | 0.0559 (10) | 0.0447 (8) | 0.0003 (7) | 0.0231 (7) | 0.0011 (7) |
C8 | 0.0392 (8) | 0.0485 (9) | 0.0327 (7) | −0.0043 (7) | 0.0182 (6) | −0.0026 (6) |
C9 | 0.0465 (9) | 0.0466 (9) | 0.0669 (11) | −0.0023 (8) | 0.0269 (8) | −0.0100 (8) |
C10 | 0.0692 (13) | 0.0590 (12) | 0.0808 (14) | 0.0115 (10) | 0.0331 (11) | 0.0122 (11) |
C11 | 0.0481 (9) | 0.0526 (10) | 0.0605 (10) | 0.0039 (8) | 0.0302 (8) | −0.0069 (8) |
C12 | 0.0639 (12) | 0.0498 (10) | 0.0673 (12) | 0.0076 (9) | 0.0214 (10) | −0.0022 (9) |
Cl1—C5 | 1.7407 (19) | C6—C7 | 1.378 (3) |
O1—C1 | 1.212 (2) | C7—H7 | 0.9300 |
O2—C2 | 1.213 (2) | C7—C8 | 1.399 (2) |
N1—C1 | 1.364 (2) | C9—H9A | 0.9700 |
N1—C8 | 1.404 (2) | C9—H9B | 0.9700 |
N1—C9 | 1.474 (2) | C9—C10 | 1.505 (3) |
N2—C2 | 1.359 (2) | C10—H10A | 0.9600 |
N2—C3 | 1.406 (2) | C10—H10B | 0.9600 |
N2—C11 | 1.473 (2) | C10—H10C | 0.9600 |
C1—C2 | 1.516 (3) | C11—H11A | 0.9700 |
C3—C4 | 1.391 (2) | C11—H11B | 0.9700 |
C3—C8 | 1.402 (2) | C11—C12 | 1.510 (3) |
C4—H4 | 0.9300 | C12—H12A | 0.9600 |
C4—C5 | 1.380 (2) | C12—H12B | 0.9600 |
C5—C6 | 1.373 (3) | C12—H12C | 0.9600 |
C6—H6 | 0.9300 | ||
C1—N1—C8 | 122.40 (15) | C3—C8—N1 | 119.77 (14) |
C1—N1—C9 | 116.90 (15) | C7—C8—N1 | 120.93 (16) |
C8—N1—C9 | 120.69 (14) | C7—C8—C3 | 119.30 (16) |
C2—N2—C3 | 122.07 (15) | N1—C9—H9A | 109.2 |
C2—N2—C11 | 116.65 (14) | N1—C9—H9B | 109.2 |
C3—N2—C11 | 121.12 (14) | N1—C9—C10 | 112.20 (16) |
O1—C1—N1 | 123.32 (18) | H9A—C9—H9B | 107.9 |
O1—C1—C2 | 119.13 (16) | C10—C9—H9A | 109.2 |
N1—C1—C2 | 117.55 (16) | C10—C9—H9B | 109.2 |
O2—C2—N2 | 122.68 (18) | C9—C10—H10A | 109.5 |
O2—C2—C1 | 118.88 (17) | C9—C10—H10B | 109.5 |
N2—C2—C1 | 118.43 (15) | C9—C10—H10C | 109.5 |
C4—C3—N2 | 120.94 (15) | H10A—C10—H10B | 109.5 |
C4—C3—C8 | 119.39 (15) | H10A—C10—H10C | 109.5 |
C8—C3—N2 | 119.67 (15) | H10B—C10—H10C | 109.5 |
C3—C4—H4 | 120.3 | N2—C11—H11A | 109.3 |
C5—C4—C3 | 119.45 (17) | N2—C11—H11B | 109.3 |
C5—C4—H4 | 120.3 | N2—C11—C12 | 111.54 (15) |
C4—C5—Cl1 | 118.37 (15) | H11A—C11—H11B | 108.0 |
C6—C5—Cl1 | 119.48 (14) | C12—C11—H11A | 109.3 |
C6—C5—C4 | 122.15 (17) | C12—C11—H11B | 109.3 |
C5—C6—H6 | 120.7 | C11—C12—H12A | 109.5 |
C5—C6—C7 | 118.69 (16) | C11—C12—H12B | 109.5 |
C7—C6—H6 | 120.7 | C11—C12—H12C | 109.5 |
C6—C7—H7 | 119.5 | H12A—C12—H12B | 109.5 |
C6—C7—C8 | 121.02 (17) | H12A—C12—H12C | 109.5 |
C8—C7—H7 | 119.5 | H12B—C12—H12C | 109.5 |
Cl1—C5—C6—C7 | −179.16 (13) | C4—C3—C8—N1 | −179.12 (14) |
O1—C1—C2—O2 | 2.5 (3) | C4—C3—C8—C7 | 0.8 (2) |
O1—C1—C2—N2 | −177.21 (17) | C4—C5—C6—C7 | 0.7 (3) |
N1—C1—C2—O2 | −177.15 (16) | C5—C6—C7—C8 | 0.1 (2) |
N1—C1—C2—N2 | 3.1 (2) | C6—C7—C8—N1 | 179.05 (15) |
N2—C3—C4—C5 | −179.83 (13) | C6—C7—C8—C3 | −0.9 (2) |
N2—C3—C8—N1 | 0.7 (2) | C8—N1—C1—O1 | 179.63 (17) |
N2—C3—C8—C7 | −179.38 (13) | C8—N1—C1—C2 | −0.7 (2) |
C1—N1—C8—C3 | −1.2 (2) | C8—N1—C9—C10 | −81.9 (2) |
C1—N1—C8—C7 | 178.90 (14) | C8—C3—C4—C5 | 0.0 (2) |
C1—N1—C9—C10 | 97.43 (19) | C9—N1—C1—O1 | 0.3 (3) |
C2—N2—C3—C4 | −178.34 (15) | C9—N1—C1—C2 | 179.98 (15) |
C2—N2—C3—C8 | 1.8 (2) | C9—N1—C8—C3 | 178.14 (14) |
C2—N2—C11—C12 | 93.20 (19) | C9—N1—C8—C7 | −1.8 (2) |
C3—N2—C2—O2 | 176.57 (16) | C11—N2—C2—O2 | 1.1 (3) |
C3—N2—C2—C1 | −3.7 (2) | C11—N2—C2—C1 | −179.15 (15) |
C3—N2—C11—C12 | −82.3 (2) | C11—N2—C3—C4 | −3.1 (2) |
C3—C4—C5—Cl1 | 179.10 (12) | C11—N2—C3—C8 | 177.12 (14) |
C3—C4—C5—C6 | −0.8 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7···O2i | 0.93 | 2.53 | 3.440 (2) | 167 |
C9—H9B···O2i | 0.97 | 2.35 | 3.180 (2) | 144 |
Symmetry code: (i) x−1/2, −y+1, z. |
Acknowledgements
JPJ acknowledges the NSF–MRI program (Grant No. CHE-1039027) for funds to purchase the X-ray diffractometer.
References
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