3-(4-Fluoro-phen-yl)-6-meth-oxy-2-(4-pyrid-yl)quinoxaline.

In the title compound, C(20)H(14)FN(3)O, the quinoxaline system makes dihedral angles of 32.38 (7) and 48.04 (7)° with the 4-fluoro-phenyl and pyridine rings, respectively. The 4-fluoro-phenyl ring makes a dihedral angle of 57.77 (9)° with the pyridine ring. In the crystal, the mol-ecules form dimeric C-H⋯N hydrogen-bonded R(2) (2)(20) ring motifs lying about crystallographic inversion centers. The dimeric units stack via π-π inter-actions between methoxy-phenyl rings and pyridine-fluoro-phenyl rings with centroid-centroid distances of 3.720 (1) and 3.823 (1) Å, respectively. The respective average perpendicular distances are 3.421 and 3.378 Å, with dihedral angles between the rings of 1.31 (9) and 11.64 (9)°.

Related literature

Many chinoxaline derivatives have been prepared and their biological activity have been studied, see: He et al. (2003 ▶); Kim et al. (2004 ▶). For inter­molecular C—H⋯N hydrogen bonds, see: Taylor & Kennard (1982 ▶). For distinct ring motifs formed via O—H⋯N hydrogen bonds, see: Habib & Janiak (2008 ▶); Friščič & MacGillivray (2003 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C20H14FN3O

M = 331.34

Orthorhombic,

a = 7.3886 (4) Å

b = 12.2071 (8) Å

c = 34.562 (6) Å

V = 3117.3 (6) Å3

Z = 8

Cu Kα radiation

μ = 0.80 mm−1

T = 193 K

0.45 × 0.22 × 0.13 mm

Data collection

Enraf–Nonius CAD-4 diffractometer

Absorption correction: none

2950 measured reflections

2950 independent reflections

2542 reflections with I > 2σ(I)

3 standard reflections frequency: 60 min intensity decay: 2%

Refinement

R[F 2 > 2σ(F 2)] = 0.044

wR(F 2) = 0.124

S = 1.05

2950 reflections

228 parameters

H-atom parameters constrained

Δρmax = 0.32 e Å−3

Δρmin = −0.24 e Å−3

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ▶); cell refinement: CAD-4 Software; data reduction: CORINC (Dräger & Gattow, 1971 ▶); program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: PLATON.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809022119/si2176sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809022119/si2176Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C20H14FN3O	F(000) = 1376
Mr = 331.34	Dx = 1.412 Mg m−3
Orthorhombic, Pbca	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 25 reflections
a = 7.3886 (4) Å	θ = 61–69°
b = 12.2071 (8) Å	µ = 0.80 mm−1
c = 34.562 (6) Å	T = 193 K
V = 3117.3 (6) Å3	Plate, colourless
Z = 8	0.45 × 0.22 × 0.13 mm

Enraf–Nonius CAD-4 diffractometer	Rint = 0.0000
Radiation source: FR571 rotating anode	θmax = 70.1°, θmin = 2.6°
graphite	h = 0→8
ω/2θ scans	k = 0→14
2950 measured reflections	l = 0→42
2950 independent reflections	3 standard reflections every 60 min
2542 reflections with I > 2σ(I)	intensity decay: 2%

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)] = 0.044	H-atom parameters constrained
wR(F2) = 0.124	w = 1/[σ2(Fo2) + (0.063P)2 + 1.8096P] where P = (Fo2 + 2Fc2)/3
S = 1.05	(Δ/σ)max < 0.001
2950 reflections	Δρmax = 0.32 e Å−3
228 parameters	Δρmin = −0.24 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0024 (2)

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > σ(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	0.0332 (2)	0.08992 (13)	0.65003 (5)	0.0212 (4)
C2	0.1240 (2)	−0.01069 (13)	0.64015 (5)	0.0234 (4)
N3	0.1695 (2)	−0.08283 (11)	0.66708 (4)	0.0248 (3)
C4	0.1415 (2)	−0.05500 (14)	0.70477 (5)	0.0241 (4)
C5	0.1912 (2)	−0.12816 (15)	0.73464 (5)	0.0280 (4)
H5	0.2383	−0.1984	0.7284	0.034*
C6	0.1717 (3)	−0.09798 (15)	0.77228 (5)	0.0290 (4)
H6	0.2040	−0.1478	0.7922	0.035*
C7	0.1034 (2)	0.00738 (15)	0.78208 (5)	0.0257 (4)
C8	0.0529 (2)	0.07962 (14)	0.75376 (5)	0.0253 (4)
H8	0.0074	0.1499	0.7604	0.030*
C9	0.0691 (2)	0.04866 (14)	0.71462 (5)	0.0224 (4)
N10	0.01133 (19)	0.11909 (11)	0.68664 (4)	0.0228 (3)
C11	−0.0457 (2)	0.16507 (13)	0.62087 (5)	0.0214 (4)
C12	−0.0501 (2)	0.27756 (14)	0.62867 (5)	0.0240 (4)
H12	0.0020	0.3047	0.6519	0.029*
C13	−0.1297 (3)	0.34958 (14)	0.60292 (5)	0.0277 (4)
H13	−0.1341	0.4258	0.6084	0.033*
C14	−0.2026 (2)	0.30841 (15)	0.56913 (5)	0.0277 (4)
C15	−0.2047 (3)	0.19825 (15)	0.56049 (5)	0.0286 (4)
H15	−0.2590	0.1720	0.5374	0.034*
C16	−0.1249 (2)	0.12698 (14)	0.58669 (5)	0.0258 (4)
H16	−0.1240	0.0507	0.5813	0.031*
F17	−0.27461 (17)	0.37943 (9)	0.54317 (3)	0.0401 (3)
C18	0.1841 (2)	−0.03833 (14)	0.60030 (5)	0.0239 (4)
C19	0.1592 (3)	−0.14261 (14)	0.58520 (5)	0.0286 (4)
H19	0.0981	−0.1973	0.5998	0.034*
C20	0.2249 (3)	−0.16553 (15)	0.54863 (5)	0.0340 (4)
H20	0.2038	−0.2367	0.5385	0.041*
N21	0.3161 (2)	−0.09438 (13)	0.52658 (5)	0.0344 (4)
C22	0.3408 (3)	0.00561 (15)	0.54154 (5)	0.0317 (4)
H22	0.4053	0.0580	0.5266	0.038*
C23	0.2776 (2)	0.03680 (14)	0.57757 (5)	0.0272 (4)
H23	0.2979	0.1091	0.5867	0.033*
O24	0.09436 (18)	0.02718 (11)	0.82084 (3)	0.0324 (3)
C25	0.0370 (3)	0.13400 (17)	0.83218 (6)	0.0356 (5)
H25A	0.1183	0.1888	0.8209	0.053*
H25B	0.0400	0.1398	0.8605	0.053*
H25C	−0.0866	0.1468	0.8230	0.053*

	U11	U22	U33	U12	U13	U23
C1	0.0199 (8)	0.0226 (8)	0.0211 (8)	−0.0022 (6)	0.0009 (6)	−0.0003 (6)
C2	0.0229 (8)	0.0223 (8)	0.0248 (8)	−0.0015 (7)	0.0009 (7)	0.0012 (6)
N3	0.0253 (7)	0.0243 (7)	0.0249 (7)	0.0000 (6)	0.0026 (6)	0.0024 (6)
C4	0.0201 (8)	0.0264 (8)	0.0259 (8)	−0.0007 (7)	0.0018 (6)	0.0031 (7)
C5	0.0270 (9)	0.0260 (8)	0.0311 (9)	0.0018 (7)	0.0026 (7)	0.0058 (7)
C6	0.0267 (9)	0.0313 (9)	0.0289 (9)	0.0013 (8)	−0.0004 (7)	0.0100 (7)
C7	0.0207 (8)	0.0355 (10)	0.0209 (8)	−0.0039 (7)	0.0012 (7)	0.0049 (7)
C8	0.0237 (8)	0.0265 (8)	0.0257 (8)	−0.0004 (7)	0.0014 (7)	0.0011 (7)
C9	0.0184 (8)	0.0254 (8)	0.0234 (8)	−0.0022 (7)	0.0004 (6)	0.0038 (7)
N10	0.0225 (7)	0.0237 (7)	0.0221 (7)	−0.0001 (6)	0.0002 (6)	0.0013 (6)
C11	0.0195 (8)	0.0225 (8)	0.0220 (8)	−0.0002 (6)	0.0024 (6)	−0.0002 (6)
C12	0.0225 (8)	0.0248 (8)	0.0246 (8)	−0.0003 (6)	0.0000 (7)	−0.0019 (7)
C13	0.0293 (9)	0.0226 (8)	0.0312 (9)	0.0019 (7)	0.0014 (7)	−0.0001 (7)
C14	0.0258 (9)	0.0310 (9)	0.0263 (9)	0.0045 (7)	−0.0004 (7)	0.0068 (7)
C15	0.0283 (10)	0.0354 (9)	0.0221 (8)	0.0011 (8)	−0.0029 (7)	−0.0020 (7)
C16	0.0258 (9)	0.0245 (8)	0.0272 (8)	−0.0004 (7)	0.0006 (7)	−0.0031 (7)
F17	0.0459 (7)	0.0397 (6)	0.0347 (6)	0.0119 (5)	−0.0078 (5)	0.0092 (5)
C18	0.0219 (8)	0.0235 (8)	0.0262 (9)	0.0030 (7)	−0.0012 (7)	0.0001 (7)
C19	0.0318 (10)	0.0241 (9)	0.0300 (9)	−0.0010 (7)	0.0004 (8)	0.0014 (7)
C20	0.0444 (12)	0.0253 (9)	0.0323 (9)	−0.0019 (8)	−0.0002 (9)	−0.0058 (8)
N21	0.0429 (10)	0.0319 (8)	0.0284 (8)	0.0021 (7)	0.0025 (7)	−0.0039 (7)
C22	0.0369 (11)	0.0293 (9)	0.0288 (9)	−0.0010 (8)	0.0053 (8)	0.0017 (7)
C23	0.0303 (9)	0.0228 (8)	0.0284 (9)	−0.0008 (7)	0.0011 (7)	−0.0022 (7)
O24	0.0350 (7)	0.0406 (8)	0.0216 (6)	0.0003 (6)	−0.0003 (5)	0.0052 (5)
C25	0.0353 (11)	0.0436 (11)	0.0279 (9)	0.0009 (9)	0.0001 (8)	−0.0011 (8)

C1—N10	1.324 (2)	C13—C14	1.381 (3)
C1—C2	1.440 (2)	C13—H13	0.9500
C1—C11	1.482 (2)	C14—F17	1.356 (2)
C2—N3	1.325 (2)	C14—C15	1.378 (3)
C2—C18	1.486 (2)	C15—C16	1.387 (2)
N3—C4	1.362 (2)	C15—H15	0.9500
C4—C5	1.414 (2)	C16—H16	0.9500
C4—C9	1.416 (2)	C18—C19	1.388 (2)
C5—C6	1.360 (3)	C18—C23	1.391 (2)
C5—H5	0.9500	C19—C20	1.382 (3)
C6—C7	1.423 (3)	C19—H19	0.9500
C6—H6	0.9500	C20—N21	1.338 (3)
C7—O24	1.363 (2)	C20—H20	0.9500
C7—C8	1.369 (2)	N21—C22	1.338 (2)
C8—C9	1.410 (2)	C22—C23	1.384 (3)
C8—H8	0.9500	C22—H22	0.9500
C9—N10	1.363 (2)	C23—H23	0.9500
C11—C16	1.398 (2)	O24—C25	1.426 (2)
C11—C12	1.400 (2)	C25—H25A	0.9800
C12—C13	1.382 (2)	C25—H25B	0.9800
C12—H12	0.9500	C25—H25C	0.9800
N10—C1—C2	120.82 (15)	C12—C13—H13	120.7
N10—C1—C11	115.80 (15)	F17—C14—C15	118.43 (16)
C2—C1—C11	123.35 (15)	F17—C14—C13	118.67 (16)
N3—C2—C1	121.23 (15)	C15—C14—C13	122.89 (16)
N3—C2—C18	115.13 (15)	C14—C15—C16	117.77 (17)
C1—C2—C18	123.52 (15)	C14—C15—H15	121.1
C2—N3—C4	117.89 (15)	C16—C15—H15	121.1
N3—C4—C5	120.10 (16)	C15—C16—C11	121.39 (16)
N3—C4—C9	120.69 (15)	C15—C16—H16	119.3
C5—C4—C9	119.16 (16)	C11—C16—H16	119.3
C6—C5—C4	120.00 (17)	C19—C18—C23	117.26 (16)
C6—C5—H5	120.0	C19—C18—C2	121.15 (16)
C4—C5—H5	120.0	C23—C18—C2	121.47 (15)
C5—C6—C7	120.69 (16)	C20—C19—C18	118.88 (17)
C5—C6—H6	119.7	C20—C19—H19	120.6
C7—C6—H6	119.7	C18—C19—H19	120.6
O24—C7—C8	125.10 (17)	N21—C20—C19	124.49 (17)
O24—C7—C6	114.32 (15)	N21—C20—H20	117.8
C8—C7—C6	120.58 (16)	C19—C20—H20	117.8
C7—C8—C9	119.36 (16)	C20—N21—C22	116.18 (16)
C7—C8—H8	120.3	N21—C22—C23	123.54 (17)
C9—C8—H8	120.3	N21—C22—H22	118.2
N10—C9—C8	119.04 (15)	C23—C22—H22	118.2
N10—C9—C4	120.78 (15)	C22—C23—C18	119.64 (16)
C8—C9—C4	120.17 (15)	C22—C23—H23	120.2
C1—N10—C9	118.06 (15)	C18—C23—H23	120.2
C16—C11—C12	118.64 (16)	C7—O24—C25	116.56 (14)
C16—C11—C1	122.23 (15)	O24—C25—H25A	109.5
C12—C11—C1	119.03 (15)	O24—C25—H25B	109.5
C13—C12—C11	120.66 (16)	H25A—C25—H25B	109.5
C13—C12—H12	119.7	O24—C25—H25C	109.5
C11—C12—H12	119.7	H25A—C25—H25C	109.5
C14—C13—C12	118.61 (16)	H25B—C25—H25C	109.5
C14—C13—H13	120.7
N10—C1—C2—N3	7.9 (3)	N10—C1—C11—C12	32.8 (2)
C11—C1—C2—N3	−170.22 (16)	C2—C1—C11—C12	−149.01 (16)
N10—C1—C2—C18	−167.94 (16)	C16—C11—C12—C13	−0.6 (3)
C11—C1—C2—C18	13.9 (3)	C1—C11—C12—C13	−177.19 (16)
C1—C2—N3—C4	−5.4 (2)	C11—C12—C13—C14	−0.8 (3)
C18—C2—N3—C4	170.78 (15)	C12—C13—C14—F17	−177.56 (16)
C2—N3—C4—C5	−178.67 (16)	C12—C13—C14—C15	2.1 (3)
C2—N3—C4—C9	−1.1 (2)	F17—C14—C15—C16	177.79 (16)
N3—C4—C5—C6	176.67 (16)	C13—C14—C15—C16	−1.9 (3)
C9—C4—C5—C6	−1.0 (3)	C14—C15—C16—C11	0.4 (3)
C4—C5—C6—C7	−0.7 (3)	C12—C11—C16—C15	0.8 (3)
C5—C6—C7—O24	−178.82 (16)	C1—C11—C16—C15	177.30 (16)
C5—C6—C7—C8	1.2 (3)	N3—C2—C18—C19	46.7 (2)
O24—C7—C8—C9	−179.94 (15)	C1—C2—C18—C19	−137.24 (18)
C6—C7—C8—C9	0.0 (3)	N3—C2—C18—C23	−129.12 (18)
C7—C8—C9—N10	177.21 (16)	C1—C2—C18—C23	47.0 (3)
C7—C8—C9—C4	−1.7 (3)	C23—C18—C19—C20	−1.1 (3)
N3—C4—C9—N10	5.7 (3)	C2—C18—C19—C20	−177.09 (17)
C5—C4—C9—N10	−176.72 (16)	C18—C19—C20—N21	1.7 (3)
N3—C4—C9—C8	−175.42 (15)	C19—C20—N21—C22	−1.0 (3)
C5—C4—C9—C8	2.2 (3)	C20—N21—C22—C23	−0.1 (3)
C2—C1—N10—C9	−3.2 (2)	N21—C22—C23—C18	0.6 (3)
C11—C1—N10—C9	175.05 (14)	C19—C18—C23—C22	0.1 (3)
C8—C9—N10—C1	177.83 (15)	C2—C18—C23—C22	176.04 (17)
C4—C9—N10—C1	−3.2 (2)	C8—C7—O24—C25	−3.7 (3)
N10—C1—C11—C16	−143.69 (17)	C6—C7—O24—C25	176.37 (16)
C2—C1—C11—C16	34.5 (2)

D—H···A	D—H	H···A	D···A	D—H···A
C15—H15···N21i	0.95	2.44	3.368 (3)	165

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C15—H15⋯N21i	0.95	2.44	3.368 (3)	165

Symmetry code: (i) .