3-(4-Meth­oxy­phen­yl)pyrido[2,3-b]pyrazine

Abstract

In the title mol­ecule, C₁₄H₁₁N₃O, the benzene ring is twisted by 14.0 (2)° from the plane through the fused ring system. In the crystal, π–π inter­actions [centroid–centroid distances = 3.609 (1), 3.639 (1) and 3.735 (1) Å] form stacks of mol­ecules propagating along the b axis. The crystal packing is further stabilized by weak inter­molecular C—H⋯O and C—H⋯N hydrogen bonds.

Related literature

For a related structure, see: Koch et al. (2009 ▶). For the pharma­cological properties of quinoxaline compounds, see: Kleim et al. (1995 ▶); Abasolo et al. (1987 ▶); Rodrigo et al. (2002 ▶).

Experimental

Crystal data

• C₁₄H₁₁N₃O

• M _r = 237.26

• Monoclinic,

• a = 6.4486 (13) Å

• b = 7.3265 (15) Å

• c = 24.216 (6) Å

• β = 99.31 (3)°

• V = 1129.0 (4) ų

• Z = 4

• Mo Kα radiation

• μ = 0.09 mm⁻¹

• T = 153 K

• 0.20 × 0.18 × 0.12 mm

Data collection

• Rigaku Saturn CCD area-detector diffractometer

• Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005 ▶) T _min = 0.982, T _max = 0.989

• 9650 measured reflections

• 2677 independent reflections

• 2221 reflections with I > 2σ(I)

• R _int = 0.034

Refinement

• R[F ² > 2σ(F ²)] = 0.049

• wR(F ²) = 0.146

• S = 1.09

• 2677 reflections

• 165 parameters

• H-atom parameters constrained

• Δρ_max = 0.39 e Å⁻³

• Δρ_min = −0.27 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C6—H6⋯N3i	0.95	2.54	3.361 (2)	145
C3—H3⋯O1ii	0.95	2.44	3.123 (2)	129

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

Functionalized quinoxalines represent an important class of nitrogen-containing heterocycle which display a broad spectrum of biological activity. Similar structure had been reported by Koch (Koch et al., 2009). Quinoxaline derivatives were found to exhibit antimicrobial (Kleim et al. 1995), antitumor (Abasolo et al.,1987), and antituberculous activity (Rodrigo et al., 2002). Here, we report the synthesis and crystal structure of the title compound, (I) (Fig. 1).

The molecular structure of title compound (I) is as shown in Fig.1. The dihedral angle between the pyrido[2,3-b]pyrazine ring and benzene ring is 14.0 (2)°. The O atom attached to the phenyl ring don't deviate the phenyl ring with an r.m.s deviation of 0.0047 (3) Å. As a result of π-π conjugation, the C_sp²-O bond [O1—C9 = 1.3656 (13) Å] is significantly shorter than the C_sp³-O bond [O1—C14 = 1.4266 (15) Å]. The crystal structure is stabilized by weak C—H···N and C—H···O intermolecular interactions and π-π interactions between the Cg1 (centroid of N1/C1—C5) and Cg2 (centroid of C1/C2/N3/C6/C7/N2). Selected geometric parameters are shown in Table 1.

Experimental

A suspension of 2-(4-methoxyphenyl)-2-oxoacetaldehyde (2.0 mmol) and pyridine-2,3-diamine (3.0 mmol) in ethanol (5 ml) was stirred at room temperature. The reaction progress was monitored via TLC. The resulting precipitate was filtered off, washed with cold ethanol, dried and purified to give the target product as light yellow solid in 93% yield. Crystals of (I) suitable for single-crystal X-ray analysis were grown by slow evaporation of a solution in chloroform-ethanol (1:1).

Refinement

All H atoms were positioned geometrically (C—H = 0.95–0.98 Å) and allowed to ride on their parent atoms, with U_iso(H) = 1.2-1.5U_eq of the parent atom.

Figures

Fig. 1.

View of the molecule of (I) showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.

Crystal data

C14H11N3O	F(000) = 496
Mr = 237.26	Dx = 1.396 Mg m−3
Monoclinic, P21/c	Melting point: 428 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 6.4486 (13) Å	Cell parameters from 3162 reflections
b = 7.3265 (15) Å	θ = 2.6–27.9°
c = 24.216 (6) Å	µ = 0.09 mm−1
β = 99.31 (3)°	T = 153 K
V = 1129.0 (4) Å3	Prism, colourless
Z = 4	0.20 × 0.18 × 0.12 mm

Data collection

Rigaku Saturn CCD area-detector diffractometer	2677 independent reflections
Radiation source: rotating anode	2221 reflections with I > 2σ(I)
multilayer	Rint = 0.034
Detector resolution: 7.31 pixels mm-1	θmax = 27.9°, θmin = 1.7°
φ and ω scans	h = −8→8
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005)	k = −9→9
Tmin = 0.982, Tmax = 0.989	l = −19→31
9650 measured reflections

Refinement

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)] = 0.049	H-atom parameters constrained
wR(F2) = 0.146	w = 1/[σ2(Fo2) + (0.0916P)2 + 0.0926P] where P = (Fo2 + 2Fc2)/3
S = 1.09	(Δ/σ)max = 0.001
2677 reflections	Δρmax = 0.39 e Å−3
165 parameters	Δρmin = −0.27 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: 0.194 (16)

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.71204 (14)	0.63090 (12)	0.31035 (3)	0.0269 (3)
N1	1.25315 (15)	0.85321 (13)	0.01789 (4)	0.0217 (3)
N2	1.03617 (15)	0.75236 (12)	0.07944 (4)	0.0194 (3)
N3	0.73020 (15)	0.63878 (13)	−0.01163 (4)	0.0212 (3)
C1	1.06896 (17)	0.77325 (15)	0.02545 (5)	0.0180 (3)
C2	0.91672 (17)	0.71404 (15)	−0.02001 (5)	0.0187 (3)
C3	0.95826 (18)	0.73760 (16)	−0.07480 (5)	0.0221 (3)
H3	0.8603	0.6979	−0.1061	0.027*
C4	1.14169 (19)	0.81838 (16)	−0.08199 (5)	0.0237 (3)
H4	1.1734	0.8377	−0.1185	0.028*
C5	1.28488 (19)	0.87344 (16)	−0.03427 (5)	0.0228 (3)
H5	1.4127	0.9288	−0.0402	0.027*
C6	0.70072 (18)	0.62433 (15)	0.04042 (5)	0.0211 (3)
H6	0.5715	0.5753	0.0477	0.025*
C7	0.85538 (17)	0.67952 (15)	0.08691 (5)	0.0181 (3)
C8	0.81251 (17)	0.65886 (15)	0.14497 (5)	0.0193 (3)
C9	0.93848 (19)	0.75321 (17)	0.18866 (5)	0.0245 (3)
H9	1.0513	0.8266	0.1806	0.029*
C10	0.90077 (19)	0.74085 (17)	0.24297 (5)	0.0253 (3)
H10	0.9865	0.8063	0.2719	0.030*
C11	0.73669 (19)	0.63212 (15)	0.25539 (5)	0.0210 (3)
C12	0.61082 (19)	0.53616 (16)	0.21299 (5)	0.0235 (3)
H12	0.4993	0.4616	0.2213	0.028*
C13	0.65008 (18)	0.55069 (16)	0.15829 (5)	0.0227 (3)
H13	0.5640	0.4852	0.1294	0.027*
C14	0.5489 (2)	0.52103 (19)	0.32631 (5)	0.0320 (3)
H14A	0.4121	0.5671	0.3081	0.048*
H14B	0.5564	0.5260	0.3670	0.048*
H14C	0.5662	0.3945	0.3147	0.048*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0318 (5)	0.0324 (5)	0.0180 (5)	−0.0071 (4)	0.0082 (3)	−0.0017 (3)
N1	0.0205 (5)	0.0225 (5)	0.0226 (5)	−0.0010 (4)	0.0050 (4)	−0.0004 (4)
N2	0.0200 (5)	0.0199 (5)	0.0185 (5)	−0.0010 (4)	0.0034 (4)	−0.0008 (4)
N3	0.0191 (5)	0.0233 (5)	0.0204 (5)	−0.0008 (4)	0.0013 (4)	0.0005 (4)
C1	0.0182 (5)	0.0172 (5)	0.0186 (6)	0.0012 (4)	0.0024 (4)	−0.0007 (4)
C2	0.0189 (5)	0.0167 (5)	0.0203 (6)	0.0017 (4)	0.0026 (4)	0.0005 (4)
C3	0.0245 (6)	0.0225 (6)	0.0185 (6)	0.0018 (4)	0.0008 (4)	0.0003 (4)
C4	0.0280 (6)	0.0241 (6)	0.0201 (6)	0.0021 (5)	0.0069 (4)	0.0019 (5)
C5	0.0218 (6)	0.0223 (6)	0.0253 (6)	−0.0002 (4)	0.0069 (4)	0.0002 (4)
C6	0.0183 (5)	0.0229 (6)	0.0220 (6)	−0.0020 (4)	0.0029 (4)	0.0001 (4)
C7	0.0185 (5)	0.0164 (5)	0.0194 (6)	0.0005 (4)	0.0032 (4)	−0.0010 (4)
C8	0.0203 (5)	0.0194 (5)	0.0183 (6)	−0.0003 (4)	0.0032 (4)	−0.0011 (4)
C9	0.0241 (6)	0.0278 (6)	0.0218 (6)	−0.0078 (5)	0.0046 (4)	−0.0012 (4)
C10	0.0277 (6)	0.0283 (7)	0.0192 (6)	−0.0066 (5)	0.0015 (5)	−0.0032 (5)
C11	0.0244 (6)	0.0216 (6)	0.0178 (6)	0.0007 (4)	0.0058 (4)	0.0000 (4)
C12	0.0242 (6)	0.0230 (6)	0.0247 (6)	−0.0053 (4)	0.0080 (5)	−0.0017 (5)
C13	0.0247 (6)	0.0229 (6)	0.0209 (6)	−0.0045 (4)	0.0048 (4)	−0.0041 (4)
C14	0.0340 (7)	0.0412 (8)	0.0241 (6)	−0.0085 (6)	0.0141 (5)	−0.0009 (5)

Geometric parameters (Å, °)

O1—C11	1.3656 (13)	C6—H6	0.9500
O1—C14	1.4266 (15)	C7—C8	1.4838 (15)
N1—C5	1.3203 (15)	C8—C13	1.3924 (16)
N1—C1	1.3630 (14)	C8—C9	1.4069 (16)
N2—C7	1.3210 (14)	C9—C10	1.3786 (16)
N2—C1	1.3662 (14)	C9—H9	0.9500
N3—C6	1.3089 (15)	C10—C11	1.3955 (16)
N3—C2	1.3678 (15)	C10—H10	0.9500
C1—C2	1.4192 (16)	C11—C12	1.3921 (17)
C2—C3	1.4061 (15)	C12—C13	1.3922 (16)
C3—C4	1.3588 (17)	C12—H12	0.9500
C3—H3	0.9500	C13—H13	0.9500
C4—C5	1.4161 (17)	C14—H14A	0.9800
C4—H4	0.9500	C14—H14B	0.9800
C5—H5	0.9500	C14—H14C	0.9800
C6—C7	1.4361 (16)
Cg1···Cg2i	3.639 (1)	Cg2···Cg2ii	3.735 (1)
Cg1···Cg2ii	3.609 (1)
C11—O1—C14	118.35 (9)	C13—C8—C9	118.02 (11)
C5—N1—C1	116.75 (10)	C13—C8—C7	122.69 (10)
C7—N2—C1	116.94 (10)	C9—C8—C7	119.28 (10)
C6—N3—C2	116.34 (9)	C10—C9—C8	121.05 (11)
N1—C1—N2	116.73 (10)	C10—C9—H9	119.5
N1—C1—C2	122.39 (11)	C8—C9—H9	119.5
N2—C1—C2	120.88 (10)	C9—C10—C11	120.00 (11)
N3—C2—C3	119.72 (10)	C9—C10—H10	120.0
N3—C2—C1	121.51 (11)	C11—C10—H10	120.0
C3—C2—C1	118.75 (11)	O1—C11—C12	124.73 (11)
C4—C3—C2	118.49 (11)	O1—C11—C10	115.19 (10)
C4—C3—H3	120.8	C12—C11—C10	120.08 (11)
C2—C3—H3	120.8	C11—C12—C13	119.28 (11)
C3—C4—C5	119.06 (11)	C11—C12—H12	120.4
C3—C4—H4	120.5	C13—C12—H12	120.4
C5—C4—H4	120.5	C12—C13—C8	121.56 (11)
N1—C5—C4	124.56 (11)	C12—C13—H13	119.2
N1—C5—H5	117.7	C8—C13—H13	119.2
C4—C5—H5	117.7	O1—C14—H14A	109.5
N3—C6—C7	122.78 (11)	O1—C14—H14B	109.5
N3—C6—H6	118.6	H14A—C14—H14B	109.5
C7—C6—H6	118.6	O1—C14—H14C	109.5
N2—C7—C6	121.51 (11)	H14A—C14—H14C	109.5
N2—C7—C8	118.35 (10)	H14B—C14—H14C	109.5
C6—C7—C8	120.13 (10)
C5—N1—C1—N2	−179.99 (9)	N3—C6—C7—N2	1.49 (17)
C5—N1—C1—C2	−0.10 (17)	N3—C6—C7—C8	−179.77 (10)
C7—N2—C1—N1	178.19 (9)	N2—C7—C8—C13	−166.08 (10)
C7—N2—C1—C2	−1.70 (16)	C6—C7—C8—C13	15.13 (16)
C6—N3—C2—C3	−178.71 (10)	N2—C7—C8—C9	14.63 (16)
C6—N3—C2—C1	−0.13 (17)	C6—C7—C8—C9	−164.15 (11)
N1—C1—C2—N3	−178.12 (9)	C13—C8—C9—C10	−0.79 (17)
N2—C1—C2—N3	1.77 (17)	C7—C8—C9—C10	178.54 (10)
N1—C1—C2—C3	0.47 (17)	C8—C9—C10—C11	0.59 (18)
N2—C1—C2—C3	−179.64 (9)	C14—O1—C11—C12	1.36 (17)
N3—C2—C3—C4	177.79 (10)	C14—O1—C11—C10	−179.27 (10)
C1—C2—C3—C4	−0.83 (17)	C9—C10—C11—O1	−179.45 (10)
C2—C3—C4—C5	0.83 (17)	C9—C10—C11—C12	−0.05 (18)
C1—N1—C5—C4	0.10 (17)	O1—C11—C12—C13	179.06 (10)
C3—C4—C5—N1	−0.48 (18)	C10—C11—C12—C13	−0.28 (17)
C2—N3—C6—C7	−1.43 (16)	C11—C12—C13—C8	0.06 (17)
C1—N2—C7—C6	0.18 (16)	C9—C8—C13—C12	0.46 (17)
C1—N2—C7—C8	−178.59 (9)	C7—C8—C13—C12	−178.84 (10)

Symmetry codes: (i) −x+2, −y+2, −z; (ii) −x+2, −y+1, −z.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···N3iii	0.95	2.54	3.361 (2)	145
C3—H3···O1iv	0.95	2.44	3.123 (2)	129

Symmetry codes: (iii) −x+1, −y+1, −z; (iv) x, −y+3/2, z−1/2.