Acta Cryst. (2009). E65, o3006 [ doi:10.1107/S1600536809045991 ]
In the title compound, C18H19N3O2, the dihedral angle between the benzene rings is 20.47 (10)° and an intramolecular N-H
O hydrogen bond occurs, generating an S(5) ring. In the crystal, inversion dimers linked by pairs of N-HO hydrogen bonds lead to R22(8) loops.
2,5 Dimethyl aniline (0.67 g, 5.57 mmol) added to the suspension of 4-(Chloroacetyl)-3,4-dihydroquinoxalin-2 (1H)-one (1.25 g, 5.57 mmol and NaHCO3 (0.7 g, 8.35 mmol) in 2-propanol. The reaction mixture was refluxed for 8 h. Then reaction was monitored by TLC (CHCl3 and ethylacetate). The solid obtained on cooling was filtered, washed with chloroform and methanol. Colourless chunks of (I) were grown from an acetone DMF mixture by slow evaporation at room temperature.
The H-atoms for the aromatic (C—H = 0.93), methylene (C—H = 0.97) and methyl carbon (C—H = 0.96) atoms were geometrically placed and treated as riding atoms: with Uiso(H) = 1.2Ueq for aromatic and methylene carbon atoms and Uiso(H) = 1.5Ueq for methyl carbon atoms. The (N—H 0.85 (2)–0.91 (2) atoms were freely refined with Uiso(H) = 1.2Ueq (parent N-atom)
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).
![[Figure 1]](./hb5210fig1thm.gif)
| Fig. 1. The molecular structure of (I) showing 50% displacement ellipsoids. |
![[Figure 2]](./hb5210fig2thm.gif)
| Fig. 2. Packing diagram for (I) showing the intermolecular and intramolecular hydrogen bonding using dashed lines. The hydrogen atoms not involved in hydrogen bonding have been omitted for clarity. |
| C18H19N3O2 | Z = 2 |
| Mr = 309.36 | F(000) = 328 |
| Triclinic, P1 | Dx = 1.325 Mg m−3 |
| Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
| a = 5.3806 (2) Å | Cell parameters from 3605 reflections |
| b = 12.3580 (6) Å | θ = 3.1–25.1° |
| c = 13.2812 (6) Å | µ = 0.09 mm−1 |
| α = 62.878 (2)° | T = 296 K |
| β = 84.135 (2)° | Chunk, colourless |
| γ = 80.835 (3)° | 0.38 × 0.17 × 0.06 mm |
| V = 775.53 (6) Å3 |
| Bruker Kappa APEXII CCD diffractometer | 3803 independent reflections |
| Radiation source: fine-focus sealed tube | 2277 reflections with I > 2σ(I) |
| graphite | Rint = 0.032 |
| φ and ω scans | θmax = 28.3°, θmin = 3.1° |
| Absorption correction: multi-scan (SADABS; Bruker, 2007) | h = −7→7 |
| Tmin = 0.967, Tmax = 0.995 | k = −16→16 |
| 16710 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)] = 0.048 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.140 | H atoms treated by a mixture of independent and constrained refinement |
| S = 1.02 | w = 1/[σ2(Fo2) + (0.0583P)2 + 0.1485P] where P = (Fo2 + 2Fc2)/3 |
| 3803 reflections | (Δ/σ)max < 0.001 |
| 216 parameters | Δρmax = 0.21 e Å−3 |
| 0 restraints | Δρmin = −0.17 e Å−3 |
| C18H19N3O2 | γ = 80.835 (3)° |
| Mr = 309.36 | V = 775.53 (6) Å3 |
| Triclinic, P1 | Z = 2 |
| a = 5.3806 (2) Å | Mo Kα radiation |
| b = 12.3580 (6) Å | µ = 0.09 mm−1 |
| c = 13.2812 (6) Å | T = 296 K |
| α = 62.878 (2)° | 0.38 × 0.17 × 0.06 mm |
| β = 84.135 (2)° |
| Bruker Kappa APEXII CCD diffractometer | 3803 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2007) | 2277 reflections with I > 2σ(I) |
| Tmin = 0.967, Tmax = 0.995 | Rint = 0.032 |
| 16710 measured reflections | θmax = 28.3° |
| R[F2 > 2σ(F2)] = 0.048 | H atoms treated by a mixture of independent and constrained refinement |
| wR(F2) = 0.140 | Δρmax = 0.21 e Å−3 |
| S = 1.02 | Δρmin = −0.17 e Å−3 |
| 3803 reflections | Absolute structure: ? |
| 216 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 | 0.3267 (3) | −0.03248 (15) | 0.21118 (13) | 0.0375 (4) | |
| C2 | 0.2304 (3) | −0.09075 (17) | 0.15875 (15) | 0.0474 (4) | |
| H2 | 0.2528 | −0.0632 | 0.0809 | 0.057* | |
| C3 | 0.1012 (4) | −0.18983 (18) | 0.22234 (17) | 0.0565 (5) | |
| H3 | 0.0350 | −0.2283 | 0.1870 | 0.068* | |
| C4 | 0.0695 (4) | −0.23204 (18) | 0.33759 (17) | 0.0595 (5) | |
| H4 | −0.0191 | −0.2984 | 0.3798 | 0.071* | |
| C5 | 0.1690 (3) | −0.17607 (17) | 0.39049 (15) | 0.0527 (5) | |
| H5 | 0.1486 | −0.2050 | 0.4685 | 0.063* | |
| C6 | 0.2993 (3) | −0.07679 (15) | 0.32755 (13) | 0.0402 (4) | |
| C7 | 0.5923 (3) | 0.04788 (16) | 0.33477 (14) | 0.0432 (4) | |
| C8 | 0.6625 (3) | 0.07691 (18) | 0.21398 (13) | 0.0478 (5) | |
| H8A | 0.7148 | 0.1581 | 0.1760 | 0.057* | |
| H8B | 0.8051 | 0.0190 | 0.2119 | 0.057* | |
| C9 | 0.3822 (3) | 0.16519 (16) | 0.05055 (13) | 0.0394 (4) | |
| C10 | 0.5334 (3) | 0.27254 (16) | −0.00272 (13) | 0.0441 (4) | |
| H10A | 0.5118 | 0.3170 | 0.0424 | 0.053* | |
| H10B | 0.7110 | 0.2433 | −0.0060 | 0.053* | |
| C11 | 0.5571 (3) | 0.45478 (16) | −0.18728 (14) | 0.0446 (4) | |
| C12 | 0.4976 (3) | 0.51241 (17) | −0.30190 (15) | 0.0487 (4) | |
| C13 | 0.6002 (4) | 0.61824 (19) | −0.37152 (17) | 0.0605 (5) | |
| H13 | 0.5629 | 0.6575 | −0.4478 | 0.073* | |
| C14 | 0.7563 (4) | 0.66854 (19) | −0.33251 (18) | 0.0630 (6) | |
| H14 | 0.8178 | 0.7415 | −0.3819 | 0.076* | |
| C15 | 0.8211 (3) | 0.61092 (17) | −0.22080 (17) | 0.0521 (5) | |
| C16 | 0.7209 (3) | 0.50364 (17) | −0.14910 (15) | 0.0487 (4) | |
| H16 | 0.7643 | 0.4633 | −0.0735 | 0.058* | |
| C17 | 0.9978 (4) | 0.6614 (2) | −0.1771 (2) | 0.0713 (6) | |
| H17A | 0.9490 | 0.6454 | −0.1005 | 0.107* | |
| H17B | 0.9907 | 0.7483 | −0.2235 | 0.107* | |
| H17C | 1.1664 | 0.6229 | −0.1795 | 0.107* | |
| C18 | 0.3267 (4) | 0.4598 (2) | −0.34590 (16) | 0.0609 (5) | |
| H18A | 0.3982 | 0.3782 | −0.3324 | 0.091* | |
| H18B | 0.3080 | 0.5101 | −0.4257 | 0.091* | |
| H18C | 0.1648 | 0.4573 | −0.3077 | 0.091* | |
| N1 | 0.4033 (3) | −0.02041 (14) | 0.38128 (12) | 0.0479 (4) | |
| N2 | 0.4571 (2) | 0.07258 (12) | 0.15222 (11) | 0.0388 (3) | |
| N3 | 0.4475 (3) | 0.35148 (15) | −0.11433 (13) | 0.0580 (5) | |
| O1 | 0.7078 (2) | 0.08343 (13) | 0.38634 (10) | 0.0589 (4) | |
| O2 | 0.2018 (2) | 0.16278 (12) | 0.00335 (10) | 0.0550 (4) | |
| H1N | 0.366 (4) | −0.0432 (18) | 0.4561 (19) | 0.066* | |
| H2N | 0.339 (4) | 0.3255 (19) | −0.1377 (17) | 0.066* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| C1 | 0.0355 (8) | 0.0409 (9) | 0.0372 (9) | −0.0074 (7) | −0.0020 (6) | −0.0174 (7) |
| C2 | 0.0535 (10) | 0.0532 (11) | 0.0437 (10) | −0.0114 (8) | −0.0022 (8) | −0.0272 (9) |
| C3 | 0.0680 (12) | 0.0528 (11) | 0.0600 (12) | −0.0194 (10) | −0.0072 (9) | −0.0305 (10) |
| C4 | 0.0696 (13) | 0.0527 (12) | 0.0557 (12) | −0.0274 (10) | −0.0070 (10) | −0.0167 (10) |
| C5 | 0.0595 (11) | 0.0560 (12) | 0.0393 (10) | −0.0209 (9) | −0.0047 (8) | −0.0137 (9) |
| C6 | 0.0400 (9) | 0.0454 (10) | 0.0383 (9) | −0.0101 (7) | −0.0055 (7) | −0.0191 (8) |
| C7 | 0.0443 (9) | 0.0476 (10) | 0.0390 (9) | −0.0101 (8) | −0.0091 (7) | −0.0175 (8) |
| C8 | 0.0396 (9) | 0.0648 (12) | 0.0395 (10) | −0.0183 (8) | −0.0044 (7) | −0.0194 (9) |
| C9 | 0.0400 (9) | 0.0481 (10) | 0.0342 (9) | −0.0092 (7) | −0.0001 (7) | −0.0211 (8) |
| C10 | 0.0457 (9) | 0.0514 (11) | 0.0371 (9) | −0.0142 (8) | −0.0029 (7) | −0.0187 (8) |
| C11 | 0.0459 (10) | 0.0438 (10) | 0.0424 (10) | −0.0066 (8) | −0.0030 (7) | −0.0173 (8) |
| C12 | 0.0508 (10) | 0.0496 (11) | 0.0418 (10) | −0.0020 (8) | −0.0040 (8) | −0.0181 (8) |
| C13 | 0.0656 (13) | 0.0581 (12) | 0.0431 (11) | −0.0049 (10) | −0.0028 (9) | −0.0106 (9) |
| C14 | 0.0669 (13) | 0.0493 (12) | 0.0608 (13) | −0.0165 (10) | 0.0107 (10) | −0.0142 (10) |
| C15 | 0.0487 (10) | 0.0501 (11) | 0.0614 (12) | −0.0123 (8) | 0.0078 (9) | −0.0284 (10) |
| C16 | 0.0520 (10) | 0.0515 (11) | 0.0437 (10) | −0.0136 (9) | −0.0019 (8) | −0.0200 (9) |
| C17 | 0.0663 (13) | 0.0734 (15) | 0.0898 (17) | −0.0316 (11) | 0.0121 (12) | −0.0459 (13) |
| C18 | 0.0656 (12) | 0.0696 (14) | 0.0475 (11) | −0.0066 (10) | −0.0132 (9) | −0.0247 (10) |
| N1 | 0.0548 (9) | 0.0629 (10) | 0.0327 (8) | −0.0240 (8) | 0.0006 (6) | −0.0224 (7) |
| N2 | 0.0381 (7) | 0.0471 (8) | 0.0331 (7) | −0.0131 (6) | −0.0024 (5) | −0.0169 (6) |
| N3 | 0.0679 (11) | 0.0545 (10) | 0.0456 (9) | −0.0250 (8) | −0.0165 (8) | −0.0090 (8) |
| O1 | 0.0667 (8) | 0.0757 (9) | 0.0453 (7) | −0.0334 (7) | −0.0050 (6) | −0.0283 (7) |
| O2 | 0.0546 (7) | 0.0619 (8) | 0.0449 (7) | −0.0206 (6) | −0.0148 (6) | −0.0140 (6) |
| C1—C6 | 1.385 (2) | C10—H10A | 0.9700 |
| C1—C2 | 1.386 (2) | C10—H10B | 0.9700 |
| C1—N2 | 1.4290 (19) | C11—N3 | 1.383 (2) |
| C2—C3 | 1.380 (2) | C11—C16 | 1.392 (2) |
| C2—H2 | 0.9300 | C11—C12 | 1.402 (2) |
| C3—C4 | 1.375 (3) | C12—C13 | 1.376 (3) |
| C3—H3 | 0.9300 | C12—C18 | 1.502 (2) |
| C4—C5 | 1.377 (2) | C13—C14 | 1.382 (3) |
| C4—H4 | 0.9300 | C13—H13 | 0.9300 |
| C5—C6 | 1.384 (2) | C14—C15 | 1.376 (3) |
| C5—H5 | 0.9300 | C14—H14 | 0.9300 |
| C6—N1 | 1.402 (2) | C15—C16 | 1.388 (2) |
| C7—O1 | 1.2233 (18) | C15—C17 | 1.504 (3) |
| C7—N1 | 1.341 (2) | C16—H16 | 0.9300 |
| C7—C8 | 1.496 (2) | C17—H17A | 0.9600 |
| C8—N2 | 1.4632 (18) | C17—H17B | 0.9600 |
| C8—H8A | 0.9700 | C17—H17C | 0.9600 |
| C8—H8B | 0.9700 | C18—H18A | 0.9600 |
| C9—O2 | 1.2192 (17) | C18—H18B | 0.9600 |
| C9—N2 | 1.361 (2) | C18—H18C | 0.9600 |
| C9—C10 | 1.514 (2) | N1—H1N | 0.91 (2) |
| C10—N3 | 1.429 (2) | N3—H2N | 0.85 (2) |
| C6—C1—C2 | 119.61 (15) | C16—C11—C12 | 119.56 (16) |
| C6—C1—N2 | 116.51 (13) | C13—C12—C11 | 117.64 (17) |
| C2—C1—N2 | 123.89 (15) | C13—C12—C18 | 121.72 (17) |
| C3—C2—C1 | 119.81 (16) | C11—C12—C18 | 120.64 (16) |
| C3—C2—H2 | 120.1 | C12—C13—C14 | 122.58 (18) |
| C1—C2—H2 | 120.1 | C12—C13—H13 | 118.7 |
| C4—C3—C2 | 120.47 (16) | C14—C13—H13 | 118.7 |
| C4—C3—H3 | 119.8 | C15—C14—C13 | 120.20 (18) |
| C2—C3—H3 | 119.8 | C15—C14—H14 | 119.9 |
| C3—C4—C5 | 120.01 (17) | C13—C14—H14 | 119.9 |
| C3—C4—H4 | 120.0 | C14—C15—C16 | 118.20 (17) |
| C5—C4—H4 | 120.0 | C14—C15—C17 | 121.24 (18) |
| C4—C5—C6 | 119.99 (17) | C16—C15—C17 | 120.56 (18) |
| C4—C5—H5 | 120.0 | C15—C16—C11 | 121.77 (17) |
| C6—C5—H5 | 120.0 | C15—C16—H16 | 119.1 |
| C5—C6—C1 | 120.08 (15) | C11—C16—H16 | 119.1 |
| C5—C6—N1 | 120.15 (15) | C15—C17—H17A | 109.5 |
| C1—C6—N1 | 119.77 (14) | C15—C17—H17B | 109.5 |
| O1—C7—N1 | 123.53 (16) | H17A—C17—H17B | 109.5 |
| O1—C7—C8 | 120.51 (15) | C15—C17—H17C | 109.5 |
| N1—C7—C8 | 115.94 (14) | H17A—C17—H17C | 109.5 |
| N2—C8—C7 | 113.34 (13) | H17B—C17—H17C | 109.5 |
| N2—C8—H8A | 108.9 | C12—C18—H18A | 109.5 |
| C7—C8—H8A | 108.9 | C12—C18—H18B | 109.5 |
| N2—C8—H8B | 108.9 | H18A—C18—H18B | 109.5 |
| C7—C8—H8B | 108.9 | C12—C18—H18C | 109.5 |
| H8A—C8—H8B | 107.7 | H18A—C18—H18C | 109.5 |
| O2—C9—N2 | 122.03 (15) | H18B—C18—H18C | 109.5 |
| O2—C9—C10 | 120.83 (15) | C7—N1—C6 | 122.90 (15) |
| N2—C9—C10 | 117.14 (13) | C7—N1—H1N | 116.9 (12) |
| N3—C10—C9 | 108.72 (12) | C6—N1—H1N | 118.9 (12) |
| N3—C10—H10A | 109.9 | C9—N2—C1 | 122.08 (12) |
| C9—C10—H10A | 109.9 | C9—N2—C8 | 123.03 (13) |
| N3—C10—H10B | 109.9 | C1—N2—C8 | 114.71 (13) |
| C9—C10—H10B | 109.9 | C11—N3—C10 | 122.78 (14) |
| H10A—C10—H10B | 108.3 | C11—N3—H2N | 120.7 (14) |
| N3—C11—C16 | 121.54 (16) | C10—N3—H2N | 115.9 (14) |
| N3—C11—C12 | 118.89 (16) | ||
| C6—C1—C2—C3 | 2.1 (3) | C13—C14—C15—C17 | 177.88 (19) |
| N2—C1—C2—C3 | −178.28 (16) | C14—C15—C16—C11 | −0.6 (3) |
| C1—C2—C3—C4 | −0.7 (3) | C17—C15—C16—C11 | −179.95 (17) |
| C2—C3—C4—C5 | −0.6 (3) | N3—C11—C16—C15 | −176.58 (18) |
| C3—C4—C5—C6 | 0.5 (3) | C12—C11—C16—C15 | 2.3 (3) |
| C4—C5—C6—C1 | 0.9 (3) | O1—C7—N1—C6 | −169.54 (17) |
| C4—C5—C6—N1 | −179.29 (17) | C8—C7—N1—C6 | 8.9 (3) |
| C2—C1—C6—C5 | −2.2 (3) | C5—C6—N1—C7 | 158.51 (17) |
| N2—C1—C6—C5 | 178.14 (15) | C1—C6—N1—C7 | −21.7 (3) |
| C2—C1—C6—N1 | 178.03 (16) | O2—C9—N2—C1 | −1.1 (3) |
| N2—C1—C6—N1 | −1.6 (2) | C10—C9—N2—C1 | 179.09 (14) |
| O1—C7—C8—N2 | −157.17 (17) | O2—C9—N2—C8 | −175.90 (16) |
| N1—C7—C8—N2 | 24.4 (2) | C10—C9—N2—C8 | 4.3 (2) |
| O2—C9—C10—N3 | −7.3 (2) | C6—C1—N2—C9 | −140.30 (16) |
| N2—C9—C10—N3 | 172.49 (15) | C2—C1—N2—C9 | 40.0 (2) |
| N3—C11—C12—C13 | 177.03 (18) | C6—C1—N2—C8 | 34.9 (2) |
| C16—C11—C12—C13 | −1.9 (3) | C2—C1—N2—C8 | −144.75 (17) |
| N3—C11—C12—C18 | −2.7 (3) | C7—C8—N2—C9 | 129.03 (17) |
| C16—C11—C12—C18 | 178.41 (17) | C7—C8—N2—C1 | −46.1 (2) |
| C11—C12—C13—C14 | −0.2 (3) | C16—C11—N3—C10 | −14.3 (3) |
| C18—C12—C13—C14 | 179.55 (19) | C12—C11—N3—C10 | 166.82 (18) |
| C12—C13—C14—C15 | 1.9 (3) | C9—C10—N3—C11 | −176.65 (17) |
| C13—C14—C15—C16 | −1.5 (3) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N3—H2N···O2 | 0.85 (2) | 2.20 (2) | 2.620 (2) | 110.0 (16) |
| N1—H1N···O1i | 0.91 (2) | 1.93 (2) | 2.8405 (19) | 176.9 (18) |
| Symmetry codes: (i) −x+1, −y, −z+1. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N3—H2N···O2 | 0.85 (2) | 2.20 (2) | 2.620 (2) | 110.0 (16) |
| N1—H1N···O1i | 0.91 (2) | 1.93 (2) | 2.8405 (19) | 176.9 (18) |
| Symmetry codes: (i) −x+1, −y, −z+1. |
WN acknowledges the Higher Education Commission, Pakistan, for providing funding for this research.
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.
Bruker (2007). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.
Khan, A. S. (2008). Eur. J. Med. Chem. 43, 2040–2044.
Miyashiro, J., Woods, K. W., Park, C. H., Liu, X., Shi, Y., Johnson, E. F., Bouska, J. J., Olson, A. M., Luo, Y., Fry, E. H., Giranda, V. L. & Penning, T. D. (2009). Bioorg. Med. Chem. Lett. 19, 4050-4054.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Spek, A. L. (2009). Acta Cryst. D65, 148–155.
Quinoxalines represent an important class of nitrogen hetrocycles possessing wide range of biological activities (e.g. Khan, 2008). Moreover, several quinoxalines have been reported as inhibitors of, e.g. poly(ADP-ribose)polymerase-1 (Miyashiro et al., 2009). During our research we tried to synthesize novel quinoxaline derivatives which may possess enhanced biological activities.
The pyrazinone ring in the quinoxaline system have gained envelop shape to some extent with the r.m.s. deviation (0.1637 A°). The intramolecular hydrogen bonding present in the molecule give rise to the formation of five membered ring motif S(5) (Bernstein, et al., 1995) which is oriented at a dihedral angle of 28.13 (0.24) ° with respect to pyrazinone ring. The dihedral angle between planar p-xylene and pyrazinone ring is 21.31 (0.09) °. Further more symmetry related N–H···O type hydrogen bonding helps to stabilize the crystal structure of the molecule by forming eight membered ring motif R228.