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ISSN: 2056-9890

4-[(2,5-Di­methyl­anilino)acet­yl]-3,4-di­hydro­quinoxalin-2(1H)-one

aInstitute of Chemistry, University of the Punjab, New Campus, Lahore, Pakistan, and bInstitute of Chemistry, Gomal University, D. I. Khan, Pakistan
*Correspondence e-mail: munawaralimunawar@yahoo.com

(Received 1 November 2009; accepted 2 November 2009; online 7 November 2009)

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—H⋯O hydrogen bonds lead to R22(8) loops.

Related literature

For background to the biological activity of quinoxalines, see: Khan (2008[Khan, A. S. (2008). Eur. J. Med. Chem. 43, 2040-2044.]); Miyashiro et al. (2009[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.]). For graph-set notation, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]).

[Scheme 1]

Experimental

Crystal data
  • C18H19N3O2

  • Mr = 309.36

  • Triclinic, [P \overline 1]

  • a = 5.3806 (2) Å

  • b = 12.3580 (6) Å

  • c = 13.2812 (6) Å

  • α = 62.878 (2)°

  • β = 84.135 (2)°

  • γ = 80.835 (3)°

  • V = 775.53 (6) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 296 K

  • 0.38 × 0.17 × 0.06 mm

Data collection
  • Bruker Kappa APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2007[Bruker (2007). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.967, Tmax = 0.995

  • 16710 measured reflections

  • 3803 independent reflections

  • 2277 reflections with I > 2σ(I)

  • Rint = 0.032

Refinement
  • R[F2 > 2σ(F2)] = 0.048

  • wR(F2) = 0.140

  • S = 1.02

  • 3803 reflections

  • 216 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.17 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA 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 code: (i) -x+1, -y, -z+1.

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2007[Bruker (2007). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and PLATON.

Supporting information


Comment top

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.

Related literature top

For background to the biological activity of quinoxalines, see: Khan (2008); Miyashiro et al. (2009). For graph-set notation, see: Bernstein et al. (1995).

Experimental top

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.

Refinement top

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)

Computing details top

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).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing 50% displacement ellipsoids.
[Figure 2] 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.
4-[(2,5-Dimethylanilino)acetyl]-3,4-dihydroquinoxalin-2(1H)-one top
Crystal data top
C18H19N3O2Z = 2
Mr = 309.36F(000) = 328
Triclinic, P1Dx = 1.325 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 5.3806 (2) ÅCell parameters from 3605 reflections
b = 12.3580 (6) Åθ = 3.1–25.1°
c = 13.2812 (6) ŵ = 0.09 mm1
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
Data collection top
Bruker Kappa APEXII CCD
diffractometer
3803 independent reflections
Radiation source: fine-focus sealed tube2277 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.032
ϕ and ω scansθmax = 28.3°, θmin = 3.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
h = 77
Tmin = 0.967, Tmax = 0.995k = 1616
16710 measured reflectionsl = 1717
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.048Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.140H 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 parametersΔρmax = 0.21 e Å3
0 restraintsΔρmin = 0.17 e Å3
Crystal data top
C18H19N3O2γ = 80.835 (3)°
Mr = 309.36V = 775.53 (6) Å3
Triclinic, P1Z = 2
a = 5.3806 (2) ÅMo Kα radiation
b = 12.3580 (6) ŵ = 0.09 mm1
c = 13.2812 (6) ÅT = 296 K
α = 62.878 (2)°0.38 × 0.17 × 0.06 mm
β = 84.135 (2)°
Data collection top
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 = 0.995Rint = 0.032
16710 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.140H atoms treated by a mixture of independent and constrained refinement
S = 1.02Δρmax = 0.21 e Å3
3803 reflectionsΔρmin = 0.17 e Å3
216 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.3267 (3)0.03248 (15)0.21118 (13)0.0375 (4)
C20.2304 (3)0.09075 (17)0.15875 (15)0.0474 (4)
H20.25280.06320.08090.057*
C30.1012 (4)0.18983 (18)0.22234 (17)0.0565 (5)
H30.03500.22830.18700.068*
C40.0695 (4)0.23204 (18)0.33759 (17)0.0595 (5)
H40.01910.29840.37980.071*
C50.1690 (3)0.17607 (17)0.39049 (15)0.0527 (5)
H50.14860.20500.46850.063*
C60.2993 (3)0.07679 (15)0.32755 (13)0.0402 (4)
C70.5923 (3)0.04788 (16)0.33477 (14)0.0432 (4)
C80.6625 (3)0.07691 (18)0.21398 (13)0.0478 (5)
H8A0.71480.15810.17600.057*
H8B0.80510.01900.21190.057*
C90.3822 (3)0.16519 (16)0.05055 (13)0.0394 (4)
C100.5334 (3)0.27254 (16)0.00272 (13)0.0441 (4)
H10A0.51180.31700.04240.053*
H10B0.71100.24330.00600.053*
C110.5571 (3)0.45478 (16)0.18728 (14)0.0446 (4)
C120.4976 (3)0.51241 (17)0.30190 (15)0.0487 (4)
C130.6002 (4)0.61824 (19)0.37152 (17)0.0605 (5)
H130.56290.65750.44780.073*
C140.7563 (4)0.66854 (19)0.33251 (18)0.0630 (6)
H140.81780.74150.38190.076*
C150.8211 (3)0.61092 (17)0.22080 (17)0.0521 (5)
C160.7209 (3)0.50364 (17)0.14910 (15)0.0487 (4)
H160.76430.46330.07350.058*
C170.9978 (4)0.6614 (2)0.1771 (2)0.0713 (6)
H17A0.94900.64540.10050.107*
H17B0.99070.74830.22350.107*
H17C1.16640.62290.17950.107*
C180.3267 (4)0.4598 (2)0.34590 (16)0.0609 (5)
H18A0.39820.37820.33240.091*
H18B0.30800.51010.42570.091*
H18C0.16480.45730.30770.091*
N10.4033 (3)0.02041 (14)0.38128 (12)0.0479 (4)
N20.4571 (2)0.07258 (12)0.15222 (11)0.0388 (3)
N30.4475 (3)0.35148 (15)0.11433 (13)0.0580 (5)
O10.7078 (2)0.08343 (13)0.38634 (10)0.0589 (4)
O20.2018 (2)0.16278 (12)0.00335 (10)0.0550 (4)
H1N0.366 (4)0.0432 (18)0.4561 (19)0.066*
H2N0.339 (4)0.3255 (19)0.1377 (17)0.066*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0355 (8)0.0409 (9)0.0372 (9)0.0074 (7)0.0020 (6)0.0174 (7)
C20.0535 (10)0.0532 (11)0.0437 (10)0.0114 (8)0.0022 (8)0.0272 (9)
C30.0680 (12)0.0528 (11)0.0600 (12)0.0194 (10)0.0072 (9)0.0305 (10)
C40.0696 (13)0.0527 (12)0.0557 (12)0.0274 (10)0.0070 (10)0.0167 (10)
C50.0595 (11)0.0560 (12)0.0393 (10)0.0209 (9)0.0047 (8)0.0137 (9)
C60.0400 (9)0.0454 (10)0.0383 (9)0.0101 (7)0.0055 (7)0.0191 (8)
C70.0443 (9)0.0476 (10)0.0390 (9)0.0101 (8)0.0091 (7)0.0175 (8)
C80.0396 (9)0.0648 (12)0.0395 (10)0.0183 (8)0.0044 (7)0.0194 (9)
C90.0400 (9)0.0481 (10)0.0342 (9)0.0092 (7)0.0001 (7)0.0211 (8)
C100.0457 (9)0.0514 (11)0.0371 (9)0.0142 (8)0.0029 (7)0.0187 (8)
C110.0459 (10)0.0438 (10)0.0424 (10)0.0066 (8)0.0030 (7)0.0173 (8)
C120.0508 (10)0.0496 (11)0.0418 (10)0.0020 (8)0.0040 (8)0.0181 (8)
C130.0656 (13)0.0581 (12)0.0431 (11)0.0049 (10)0.0028 (9)0.0106 (9)
C140.0669 (13)0.0493 (12)0.0608 (13)0.0165 (10)0.0107 (10)0.0142 (10)
C150.0487 (10)0.0501 (11)0.0614 (12)0.0123 (8)0.0078 (9)0.0284 (10)
C160.0520 (10)0.0515 (11)0.0437 (10)0.0136 (9)0.0019 (8)0.0200 (9)
C170.0663 (13)0.0734 (15)0.0898 (17)0.0316 (11)0.0121 (12)0.0459 (13)
C180.0656 (12)0.0696 (14)0.0475 (11)0.0066 (10)0.0132 (9)0.0247 (10)
N10.0548 (9)0.0629 (10)0.0327 (8)0.0240 (8)0.0006 (6)0.0224 (7)
N20.0381 (7)0.0471 (8)0.0331 (7)0.0131 (6)0.0024 (5)0.0169 (6)
N30.0679 (11)0.0545 (10)0.0456 (9)0.0250 (8)0.0165 (8)0.0090 (8)
O10.0667 (8)0.0757 (9)0.0453 (7)0.0334 (7)0.0050 (6)0.0283 (7)
O20.0546 (7)0.0619 (8)0.0449 (7)0.0206 (6)0.0148 (6)0.0140 (6)
Geometric parameters (Å, º) top
C1—C61.385 (2)C10—H10A0.9700
C1—C21.386 (2)C10—H10B0.9700
C1—N21.4290 (19)C11—N31.383 (2)
C2—C31.380 (2)C11—C161.392 (2)
C2—H20.9300C11—C121.402 (2)
C3—C41.375 (3)C12—C131.376 (3)
C3—H30.9300C12—C181.502 (2)
C4—C51.377 (2)C13—C141.382 (3)
C4—H40.9300C13—H130.9300
C5—C61.384 (2)C14—C151.376 (3)
C5—H50.9300C14—H140.9300
C6—N11.402 (2)C15—C161.388 (2)
C7—O11.2233 (18)C15—C171.504 (3)
C7—N11.341 (2)C16—H160.9300
C7—C81.496 (2)C17—H17A0.9600
C8—N21.4632 (18)C17—H17B0.9600
C8—H8A0.9700C17—H17C0.9600
C8—H8B0.9700C18—H18A0.9600
C9—O21.2192 (17)C18—H18B0.9600
C9—N21.361 (2)C18—H18C0.9600
C9—C101.514 (2)N1—H1N0.91 (2)
C10—N31.429 (2)N3—H2N0.85 (2)
C6—C1—C2119.61 (15)C16—C11—C12119.56 (16)
C6—C1—N2116.51 (13)C13—C12—C11117.64 (17)
C2—C1—N2123.89 (15)C13—C12—C18121.72 (17)
C3—C2—C1119.81 (16)C11—C12—C18120.64 (16)
C3—C2—H2120.1C12—C13—C14122.58 (18)
C1—C2—H2120.1C12—C13—H13118.7
C4—C3—C2120.47 (16)C14—C13—H13118.7
C4—C3—H3119.8C15—C14—C13120.20 (18)
C2—C3—H3119.8C15—C14—H14119.9
C3—C4—C5120.01 (17)C13—C14—H14119.9
C3—C4—H4120.0C14—C15—C16118.20 (17)
C5—C4—H4120.0C14—C15—C17121.24 (18)
C4—C5—C6119.99 (17)C16—C15—C17120.56 (18)
C4—C5—H5120.0C15—C16—C11121.77 (17)
C6—C5—H5120.0C15—C16—H16119.1
C5—C6—C1120.08 (15)C11—C16—H16119.1
C5—C6—N1120.15 (15)C15—C17—H17A109.5
C1—C6—N1119.77 (14)C15—C17—H17B109.5
O1—C7—N1123.53 (16)H17A—C17—H17B109.5
O1—C7—C8120.51 (15)C15—C17—H17C109.5
N1—C7—C8115.94 (14)H17A—C17—H17C109.5
N2—C8—C7113.34 (13)H17B—C17—H17C109.5
N2—C8—H8A108.9C12—C18—H18A109.5
C7—C8—H8A108.9C12—C18—H18B109.5
N2—C8—H8B108.9H18A—C18—H18B109.5
C7—C8—H8B108.9C12—C18—H18C109.5
H8A—C8—H8B107.7H18A—C18—H18C109.5
O2—C9—N2122.03 (15)H18B—C18—H18C109.5
O2—C9—C10120.83 (15)C7—N1—C6122.90 (15)
N2—C9—C10117.14 (13)C7—N1—H1N116.9 (12)
N3—C10—C9108.72 (12)C6—N1—H1N118.9 (12)
N3—C10—H10A109.9C9—N2—C1122.08 (12)
C9—C10—H10A109.9C9—N2—C8123.03 (13)
N3—C10—H10B109.9C1—N2—C8114.71 (13)
C9—C10—H10B109.9C11—N3—C10122.78 (14)
H10A—C10—H10B108.3C11—N3—H2N120.7 (14)
N3—C11—C16121.54 (16)C10—N3—H2N115.9 (14)
N3—C11—C12118.89 (16)
C6—C1—C2—C32.1 (3)C13—C14—C15—C17177.88 (19)
N2—C1—C2—C3178.28 (16)C14—C15—C16—C110.6 (3)
C1—C2—C3—C40.7 (3)C17—C15—C16—C11179.95 (17)
C2—C3—C4—C50.6 (3)N3—C11—C16—C15176.58 (18)
C3—C4—C5—C60.5 (3)C12—C11—C16—C152.3 (3)
C4—C5—C6—C10.9 (3)O1—C7—N1—C6169.54 (17)
C4—C5—C6—N1179.29 (17)C8—C7—N1—C68.9 (3)
C2—C1—C6—C52.2 (3)C5—C6—N1—C7158.51 (17)
N2—C1—C6—C5178.14 (15)C1—C6—N1—C721.7 (3)
C2—C1—C6—N1178.03 (16)O2—C9—N2—C11.1 (3)
N2—C1—C6—N11.6 (2)C10—C9—N2—C1179.09 (14)
O1—C7—C8—N2157.17 (17)O2—C9—N2—C8175.90 (16)
N1—C7—C8—N224.4 (2)C10—C9—N2—C84.3 (2)
O2—C9—C10—N37.3 (2)C6—C1—N2—C9140.30 (16)
N2—C9—C10—N3172.49 (15)C2—C1—N2—C940.0 (2)
N3—C11—C12—C13177.03 (18)C6—C1—N2—C834.9 (2)
C16—C11—C12—C131.9 (3)C2—C1—N2—C8144.75 (17)
N3—C11—C12—C182.7 (3)C7—C8—N2—C9129.03 (17)
C16—C11—C12—C18178.41 (17)C7—C8—N2—C146.1 (2)
C11—C12—C13—C140.2 (3)C16—C11—N3—C1014.3 (3)
C18—C12—C13—C14179.55 (19)C12—C11—N3—C10166.82 (18)
C12—C13—C14—C151.9 (3)C9—C10—N3—C11176.65 (17)
C13—C14—C15—C161.5 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H2N···O20.85 (2)2.20 (2)2.620 (2)110.0 (16)
N1—H1N···O1i0.91 (2)1.93 (2)2.8405 (19)176.9 (18)
Symmetry code: (i) x+1, y, z+1.

Experimental details

Crystal data
Chemical formulaC18H19N3O2
Mr309.36
Crystal system, space groupTriclinic, P1
Temperature (K)296
a, b, c (Å)5.3806 (2), 12.3580 (6), 13.2812 (6)
α, β, γ (°)62.878 (2), 84.135 (2), 80.835 (3)
V3)775.53 (6)
Z2
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.38 × 0.17 × 0.06
Data collection
DiffractometerBruker Kappa APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2007)
Tmin, Tmax0.967, 0.995
No. of measured, independent and
observed [I > 2σ(I)] reflections
16710, 3803, 2277
Rint0.032
(sin θ/λ)max1)0.667
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.140, 1.02
No. of reflections3803
No. of parameters216
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.21, 0.17

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H2N···O20.85 (2)2.20 (2)2.620 (2)110.0 (16)
N1—H1N···O1i0.91 (2)1.93 (2)2.8405 (19)176.9 (18)
Symmetry code: (i) x+1, y, z+1.
 

Acknowledgements

WN acknowledges the Higher Education Commission, Pakistan, for providing funding for this research.

References

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