2,3-Bis(3-nitro­phen­yl)quinoxaline

Lei, P.; Hu, Z.-Z.; Wang, C.-P.; Chen, X.; Zhang, Z.-Q.

doi:10.1107/S1600536807042055

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2,3-Bis(3-nitrophenyl)quinoxaline

P. Lei, Z.-Z. Hu, C.-P. Wang, X. Chen and Z.-Q. Zhang

The title compound, C₂₀H₁₂N₄O₄, contains two benzene rings ortho bonded to a quinoxaline nucleus. The dihedral angle between the benzene rings is 59.2 (4)°. The two benzene rings adopt a trans configuration with respect to the quinoxaline plane. The formal C—C σ-bond substituted by nitrophenyl groups is shorter than normal C—C bonds and the C(benzene)—C(quinoxaline) bonds. These features are consistent with electron delocalization over the whole molecule.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807042055/bh2119sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536807042055/bh2119Isup2.hkl Contains datablock I

CCDC reference: 663696

checkCIF report

Key indicators

Single-crystal X-ray study
T = 294 K
Mean (C-C) = 0.005 Å
R factor = 0.057
wR factor = 0.190
Data-to-parameter ratio = 11.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N1
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N4
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          5

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

Functionalized quinoxalines possess a wide range of biological activities, including anticancer (Lindsley et al., 2005), antiviral (Loriga et al., 1997), and antibacterial activity (Seitz et al., 2002), and have also be reported to be kinase inhibitors (He et al., 2003). Herein we report the synthesis and molecular structure of a quinoxaline derivative, (I).

In the molecular structure of (I), the two benzene rings attached to the quinoxaline nucleus make a dihedral angle of 59.2 (4)°. The quinoxaline ring is approximately planar, with a r.m.s. deviation of 0.0341 (5) Å. The two benzene rings make dihedral angles of 26.7 (4) and 58.1 (4)°, respectively, with the planar quinoxaline system. The C6—C7 and C14—C15 bond lengths linking nitrophenyl groups to the quionxaline nucleus (Table 1), are slightly shorter than the normal C—C σ bonds, as a consequence of the delocalization over the aromatic rings. Short bond length is also observed for the C7—C14 bond.

The structure of a related molecule, 2,3-diphenylquinoxaline, has been reported previously (Cantalupo et al., 2006; Rajnikant et al., 2006).

Related literature top

For related literature, see: Cantalupo et al. (2006); He et al. (2003); Lindsley et al. (2005); Loriga et al. (1997); Rajnikant et al. (2006); Seitz et al. (2002).

Experimental top

A suspension of 1,2-bis(3-nitrophenyl)ethane-1,2-dione (0.8 mmol) and benzene-1,2-diamine (1.0 mmol) in acetic acid (AcOH, 3 ml) was refluxed for 0.5 h. The mixture was poured into ice-water and a white precipitate was formed. The mixture was neutralized using saturated NaHCO₃ solution. The resulting precipitate was filtered, washed with water, dried and purified by recrystallization using a mixture of ethyl acetate/petroleum ether, giving the target product as light yellow floccules in 35% yield. Colorless crystals of (I) suitable for single-crystal X-ray analysis were grown by slow evaporation of a solution in chloroform/ethanol (1:15 v/v).

Structure description top

The structure of a related molecule, 2,3-diphenylquinoxaline, has been reported previously (Cantalupo et al., 2006; Rajnikant et al., 2006).

For related literature, see: Cantalupo et al. (2006); He et al. (2003); Lindsley et al. (2005); Loriga et al. (1997); Rajnikant et al. (2006); Seitz et al. (2002).

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXTL (Bruker, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL (Bruker, 1997).

Figures top

Fig. 1. View of the molecule of (I) showing the atom-labeling scheme. Displacement ellipsoids are drawn at the 35% probability level.

2,3-Bis(3-nitrophenyl)quinoxaline top

Crystal data top

C₂₀H₁₂N₄O₄	D_x = 1.473 Mg m⁻³
M_r = 372.34	Melting point: 484 K
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 2243 reflections
a = 12.807 (3) Å	θ = 2.3–22.5°
b = 7.6160 (15) Å	µ = 0.11 mm⁻¹
c = 34.430 (7) Å	T = 294 K
V = 3358.2 (12) Å³	Plate, colourless
Z = 8	0.22 × 0.18 × 0.12 mm
F(000) = 1536

Data collection top

Bruker SMART 1000 diffractometer	2948 independent reflections
Radiation source: fine-focus sealed tube	1533 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.083
φ and ω scans	θ_max = 25.0°, θ_min = 1.2°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −12→15
T_min = 0.977, T_max = 0.983	k = −9→6
13448 measured reflections	l = −33→40

Refinement top

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)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.190	H-atom parameters constrained
S = 1.01	w = 1/[σ²(F_o²) + (0.0892P)² + 1.3718P] where P = (F_o² + 2F_c²)/3
2948 reflections	(Δ/σ)_max < 0.001
253 parameters	Δρ_max = 0.39 e Å⁻³
0 restraints	Δρ_min = −0.25 e Å⁻³

Crystal data top

C₂₀H₁₂N₄O₄	V = 3358.2 (12) Å³
M_r = 372.34	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 12.807 (3) Å	µ = 0.11 mm⁻¹
b = 7.6160 (15) Å	T = 294 K
c = 34.430 (7) Å	0.22 × 0.18 × 0.12 mm

Data collection top

Bruker SMART 1000 diffractometer	2948 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 1997)	1533 reflections with I > 2σ(I)
T_min = 0.977, T_max = 0.983	R_int = 0.083
13448 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.057	0 restraints
wR(F²) = 0.190	H-atom parameters constrained
S = 1.01	Δρ_max = 0.39 e Å⁻³
2948 reflections	Δρ_min = −0.25 e Å⁻³
253 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.7566 (4)	1.1964 (7)	−0.02595 (10)	0.1310 (17)
O2	0.8690 (3)	1.0826 (5)	0.01110 (10)	0.0870 (11)
O3	0.2285 (3)	0.8632 (5)	0.18938 (10)	0.0883 (11)
O4	0.1405 (3)	0.7078 (6)	0.14923 (13)	0.1201 (16)
N1	0.7804 (4)	1.1237 (5)	0.00377 (10)	0.0723 (12)
N2	0.7785 (2)	0.8778 (4)	0.13906 (8)	0.0410 (8)
N3	0.6311 (2)	0.7105 (4)	0.18590 (8)	0.0425 (8)
N4	0.2227 (3)	0.7670 (6)	0.16106 (13)	0.0711 (11)
C1	0.7236 (3)	0.9972 (5)	0.06500 (10)	0.0427 (9)
H1	0.7902	0.9501	0.0677	0.051*
C2	0.6987 (3)	1.0903 (5)	0.03248 (11)	0.0510 (10)
C3	0.6010 (4)	1.1591 (5)	0.02666 (13)	0.0622 (12)
H3A	0.5843	1.2163	0.0036	0.075*
C4	0.5285 (3)	1.1413 (5)	0.05580 (13)	0.0639 (12)
H4A	0.4625	1.1908	0.0531	0.077*
C5	0.5536 (3)	1.0506 (5)	0.08894 (12)	0.0532 (11)
H5	0.5040	1.0413	0.1086	0.064*
C6	0.6500 (3)	0.9724 (5)	0.09413 (10)	0.0414 (9)
C7	0.6801 (3)	0.8727 (4)	0.12936 (9)	0.0371 (9)
C8	0.8071 (3)	0.7959 (5)	0.17225 (10)	0.0410 (9)
C9	0.9120 (3)	0.7918 (5)	0.18301 (12)	0.0526 (10)
H9	0.9621	0.8434	0.1671	0.063*
C10	0.9413 (3)	0.7126 (6)	0.21664 (12)	0.0607 (12)
H10	1.0115	0.7093	0.2235	0.073*
C11	0.8674 (4)	0.6365 (6)	0.24082 (12)	0.0590 (11)
H11	0.8884	0.5825	0.2637	0.071*
C12	0.7646 (3)	0.6403 (5)	0.23127 (10)	0.0526 (11)
H12	0.7156	0.5899	0.2478	0.063*
C13	0.7320 (3)	0.7196 (5)	0.19665 (9)	0.0397 (9)
C14	0.6066 (3)	0.7777 (5)	0.15223 (10)	0.0402 (9)
C15	0.5015 (3)	0.7331 (5)	0.13689 (10)	0.0449 (9)
C16	0.4938 (3)	0.6437 (5)	0.10190 (11)	0.0560 (11)
H16	0.5544	0.6162	0.0883	0.067*
C17	0.3983 (4)	0.5947 (6)	0.08668 (12)	0.0633 (12)
H17	0.3946	0.5342	0.0633	0.076*
C18	0.3105 (4)	0.6358 (6)	0.10632 (13)	0.0610 (12)
H18	0.2456	0.6047	0.0964	0.073*
C19	0.3170 (3)	0.7230 (5)	0.14073 (12)	0.0514 (10)
C20	0.4127 (3)	0.7711 (5)	0.15701 (11)	0.0487 (10)
H20	0.4158	0.8274	0.1809	0.058*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.141 (3)	0.177 (4)	0.075 (2)	0.057 (3)	0.027 (2)	0.065 (3)
O2	0.077 (2)	0.101 (3)	0.083 (2)	0.012 (2)	0.027 (2)	0.022 (2)
O3	0.071 (3)	0.119 (3)	0.075 (2)	0.018 (2)	0.0175 (19)	0.005 (2)
O4	0.036 (2)	0.145 (4)	0.180 (4)	−0.012 (2)	0.004 (2)	−0.018 (3)
N1	0.093 (3)	0.074 (3)	0.050 (2)	0.020 (2)	0.012 (2)	0.015 (2)
N2	0.036 (2)	0.0402 (18)	0.0466 (18)	0.0011 (14)	0.0006 (15)	−0.0021 (14)
N3	0.041 (2)	0.0475 (18)	0.0390 (17)	−0.0006 (15)	−0.0014 (14)	−0.0019 (15)
N4	0.053 (3)	0.077 (3)	0.083 (3)	0.006 (2)	0.003 (2)	0.020 (2)
C1	0.042 (2)	0.040 (2)	0.046 (2)	−0.0001 (17)	−0.0010 (19)	−0.0046 (17)
C2	0.065 (3)	0.046 (2)	0.042 (2)	−0.003 (2)	0.005 (2)	0.0032 (19)
C3	0.068 (3)	0.056 (3)	0.063 (3)	0.002 (2)	−0.014 (3)	0.012 (2)
C4	0.048 (3)	0.057 (3)	0.086 (3)	0.007 (2)	−0.004 (3)	0.017 (2)
C5	0.041 (2)	0.051 (2)	0.068 (3)	0.004 (2)	0.005 (2)	0.012 (2)
C6	0.040 (2)	0.039 (2)	0.045 (2)	−0.0027 (17)	−0.0007 (18)	−0.0040 (17)
C7	0.037 (2)	0.035 (2)	0.039 (2)	0.0015 (16)	0.0018 (17)	−0.0036 (16)
C8	0.041 (2)	0.040 (2)	0.042 (2)	0.0037 (17)	−0.0023 (18)	−0.0055 (17)
C9	0.037 (3)	0.056 (2)	0.065 (3)	0.0005 (19)	0.000 (2)	0.000 (2)
C10	0.047 (3)	0.068 (3)	0.068 (3)	0.006 (2)	−0.020 (2)	0.003 (2)
C11	0.067 (3)	0.061 (3)	0.049 (2)	0.003 (2)	−0.013 (2)	0.000 (2)
C12	0.062 (3)	0.052 (3)	0.043 (2)	−0.004 (2)	−0.001 (2)	−0.0020 (18)
C13	0.042 (2)	0.041 (2)	0.0358 (19)	0.0015 (17)	0.0007 (18)	−0.0053 (16)
C14	0.035 (2)	0.040 (2)	0.046 (2)	0.0023 (16)	0.0030 (18)	−0.0037 (17)
C15	0.043 (3)	0.045 (2)	0.047 (2)	−0.0008 (18)	0.0039 (19)	0.0084 (18)
C16	0.049 (3)	0.063 (3)	0.056 (3)	−0.002 (2)	−0.002 (2)	−0.004 (2)
C17	0.068 (3)	0.066 (3)	0.056 (3)	−0.003 (2)	−0.008 (3)	−0.008 (2)
C18	0.051 (3)	0.066 (3)	0.066 (3)	−0.006 (2)	−0.007 (2)	0.013 (2)
C19	0.040 (3)	0.052 (2)	0.062 (3)	0.000 (2)	0.007 (2)	0.014 (2)
C20	0.049 (3)	0.047 (2)	0.050 (2)	0.0025 (19)	0.004 (2)	0.0062 (18)

Geometric parameters (Å, º) top

O1—N1	1.202 (4)	C8—C9	1.394 (5)
O2—N1	1.204 (4)	C8—C13	1.403 (5)
O3—N4	1.222 (5)	C9—C10	1.358 (5)
O4—N4	1.215 (5)	C9—H9	0.9300
N1—C2	1.462 (5)	C10—C11	1.387 (6)
N2—C7	1.304 (4)	C10—H10	0.9300
N2—C8	1.353 (4)	C11—C12	1.357 (5)
N3—C14	1.305 (4)	C11—H11	0.9300
N3—C13	1.346 (4)	C12—C13	1.401 (5)
N4—C19	1.435 (5)	C12—H12	0.9300
C1—C2	1.363 (5)	C14—C15	1.485 (5)
C1—C6	1.389 (5)	C15—C20	1.363 (5)
C1—H1	0.9300	C15—C16	1.387 (5)
C2—C3	1.372 (5)	C16—C17	1.382 (5)
C3—C4	1.373 (6)	C16—H16	0.9300
C3—H3A	0.9300	C17—C18	1.349 (5)
C4—C5	1.372 (5)	C17—H17	0.9300
C4—H4A	0.9300	C18—C19	1.361 (6)
C5—C6	1.383 (5)	C18—H18	0.9300
C5—H5	0.9300	C19—C20	1.397 (5)
C6—C7	1.482 (5)	C20—H20	0.9300
C7—C14	1.425 (5)

O1—N1—O2	122.5 (4)	C8—C9—H9	119.9
O1—N1—C2	118.3 (4)	C9—C10—C11	120.6 (4)
O2—N1—C2	119.2 (4)	C9—C10—H10	119.7
C7—N2—C8	117.7 (3)	C11—C10—H10	119.7
C14—N3—C13	117.0 (3)	C12—C11—C10	120.5 (4)
O4—N4—O3	122.9 (4)	C12—C11—H11	119.7
O4—N4—C19	118.6 (5)	C10—C11—H11	119.7
O3—N4—C19	118.5 (4)	C11—C12—C13	120.3 (4)
C2—C1—C6	120.3 (4)	C11—C12—H12	119.8
C2—C1—H1	119.8	C13—C12—H12	119.8
C6—C1—H1	119.8	N3—C13—C12	119.9 (3)
C1—C2—C3	122.2 (4)	N3—C13—C8	121.0 (3)
C1—C2—N1	118.6 (4)	C12—C13—C8	118.9 (4)
C3—C2—N1	119.2 (4)	N3—C14—C7	122.1 (3)
C2—C3—C4	118.2 (4)	N3—C14—C15	116.4 (3)
C2—C3—H3A	120.9	C7—C14—C15	121.2 (3)
C4—C3—H3A	120.9	C20—C15—C16	119.1 (4)
C5—C4—C3	120.0 (4)	C20—C15—C14	121.8 (3)
C5—C4—H4A	120.0	C16—C15—C14	119.1 (3)
C3—C4—H4A	120.0	C17—C16—C15	121.7 (4)
C4—C5—C6	122.2 (4)	C17—C16—H16	119.2
C4—C5—H5	118.9	C15—C16—H16	119.2
C6—C5—H5	118.9	C18—C17—C16	119.0 (4)
C5—C6—C1	117.0 (3)	C18—C17—H17	120.5
C5—C6—C7	124.0 (3)	C16—C17—H17	120.5
C1—C6—C7	119.0 (3)	C17—C18—C19	119.9 (4)
N2—C7—C14	120.8 (3)	C17—C18—H18	120.0
N2—C7—C6	116.4 (3)	C19—C18—H18	120.0
C14—C7—C6	122.8 (3)	C18—C19—C20	122.1 (4)
N2—C8—C9	119.8 (3)	C18—C19—N4	119.1 (4)
N2—C8—C13	120.7 (3)	C20—C19—N4	118.8 (4)
C9—C8—C13	119.5 (3)	C15—C20—C19	118.2 (4)
C10—C9—C8	120.2 (4)	C15—C20—H20	120.9
C10—C9—H9	119.9	C19—C20—H20	120.9

C6—C1—C2—C3	−1.5 (6)	C11—C12—C13—C8	−0.4 (5)
C6—C1—C2—N1	175.8 (3)	N2—C8—C13—N3	6.7 (5)
O1—N1—C2—C1	175.5 (4)	C9—C8—C13—N3	−175.4 (3)
O2—N1—C2—C1	−6.6 (6)	N2—C8—C13—C12	−178.3 (3)
O1—N1—C2—C3	−7.2 (6)	C9—C8—C13—C12	−0.3 (5)
O2—N1—C2—C3	170.7 (4)	C13—N3—C14—C7	−6.3 (5)
C1—C2—C3—C4	3.8 (6)	C13—N3—C14—C15	167.0 (3)
N1—C2—C3—C4	−173.5 (4)	N2—C7—C14—N3	8.5 (5)
C2—C3—C4—C5	−2.5 (6)	C6—C7—C14—N3	−170.5 (3)
C3—C4—C5—C6	−1.0 (6)	N2—C7—C14—C15	−164.5 (3)
C4—C5—C6—C1	3.3 (6)	C6—C7—C14—C15	16.5 (5)
C4—C5—C6—C7	−179.7 (4)	N3—C14—C15—C20	58.2 (5)
C2—C1—C6—C5	−2.0 (5)	C7—C14—C15—C20	−128.4 (4)
C2—C1—C6—C7	−179.2 (3)	N3—C14—C15—C16	−119.1 (4)
C8—N2—C7—C14	−2.6 (5)	C7—C14—C15—C16	54.4 (5)
C8—N2—C7—C6	176.5 (3)	C20—C15—C16—C17	1.0 (6)
C5—C6—C7—N2	−148.7 (3)	C14—C15—C16—C17	178.3 (4)
C1—C6—C7—N2	28.2 (5)	C15—C16—C17—C18	0.4 (6)
C5—C6—C7—C14	30.3 (5)	C16—C17—C18—C19	−0.6 (6)
C1—C6—C7—C14	−152.8 (3)	C17—C18—C19—C20	−0.6 (6)
C7—N2—C8—C9	177.5 (3)	C17—C18—C19—N4	179.5 (4)
C7—N2—C8—C13	−4.6 (5)	O4—N4—C19—C18	8.2 (6)
N2—C8—C9—C10	178.8 (3)	O3—N4—C19—C18	−171.3 (4)
C13—C8—C9—C10	0.8 (6)	O4—N4—C19—C20	−171.6 (4)
C8—C9—C10—C11	−0.6 (6)	O3—N4—C19—C20	8.8 (6)
C9—C10—C11—C12	−0.1 (6)	C16—C15—C20—C19	−2.1 (5)
C10—C11—C12—C13	0.6 (6)	C14—C15—C20—C19	−179.3 (3)
C14—N3—C13—C12	−176.0 (3)	C18—C19—C20—C15	2.0 (6)
C14—N3—C13—C8	−1.0 (5)	N4—C19—C20—C15	−178.1 (3)
C11—C12—C13—N3	174.7 (3)

Experimental details

Crystal data
Chemical formula	C₂₀H₁₂N₄O₄
M_r	372.34
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	294
a, b, c (Å)	12.807 (3), 7.6160 (15), 34.430 (7)
V (Å³)	3358.2 (12)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.11
Crystal size (mm)	0.22 × 0.18 × 0.12

Data collection
Diffractometer	Bruker SMART 1000
Absorption correction	Multi-scan (SADABS; Bruker, 1997)
T_min, T_max	0.977, 0.983
No. of measured, independent and observed [I > 2σ(I)] reflections	13448, 2948, 1533
R_int	0.083
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.057, 0.190, 1.01
No. of reflections	2948
No. of parameters	253
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.39, −0.25

Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 1997), SHELXTL (Bruker, 1997).

Selected geometric parameters (Å, º) top

C6—C7	1.482 (5)	C14—C15	1.485 (5)
C7—C14	1.425 (5)

N2—C7—C6	116.4 (3)	N3—C14—C15	116.4 (3)

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