2-Isopropyl-3-methyl-quinoxaline 1,4-dioxide.

In the title compound, C(12)H(14)N(2)O(2), the quinoxaline ring system and the C atoms of the methylene and methyl substituents lie on a mirror plane. The crystal packing is stabilized by weak π-π inter-actions [centroid-centroid distance = 3.680 (7) Å].

Related literature

For the preparation, see: Issidorides & Haddadin (1966 ▶). For the biological activity of quinoxaline di-N-oxide compounds, see: Amin et al. (2006 ▶); Edwards et al. (1975 ▶); Glazer & Chappel (1982 ▶).

Experimental

Crystal data

C12H14N2O2

M = 218.25

Orthorhombic,

a = 13.3879 (10) Å

b = 6.8462 (6) Å

c = 11.8861 (9) Å

V = 1089.44 (15) Å3

Z = 4

Mo Kα radiation

μ = 0.09 mm−1

T = 296 K

0.29 × 0.27 × 0.26 mm

Data collection

Bruker APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T min = 0.651, T max = 0.745

10376 measured reflections

1446 independent reflections

1062 reflections with I > 2σ(I)

R int = 0.019

Refinement

R[F 2 > 2σ(F 2)] = 0.057

wR(F 2) = 0.203

S = 1.17

1446 reflections

96 parameters

1 restraint

H-atom parameters constrained

Δρmax = 0.38 e Å−3

Δρmin = −0.35 e Å−3

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810023706/jh2164sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810023706/jh2164Isup2.hkl

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

C12H14N2O2	Dx = 1.331 Mg m−3
Mr = 218.25	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pnma	Cell parameters from 4638 reflections
a = 13.3879 (10) Å	θ = 3.0–27.9°
b = 6.8462 (6) Å	µ = 0.09 mm−1
c = 11.8861 (9) Å	T = 296 K
V = 1089.44 (15) Å3	Block, colourless
Z = 4	0.29 × 0.27 × 0.26 mm
F(000) = 464

Bruker APEXII CCD area-detector diffractometer	1446 independent reflections
Radiation source: fine-focus sealed tube	1062 reflections with I > 2σ(I)
graphite	Rint = 0.019
φ and ω scans	θmax = 28.6°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −18→17
Tmin = 0.651, Tmax = 0.745	k = −9→9
10376 measured reflections	l = −16→16

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)] = 0.057	H-atom parameters constrained
wR(F2) = 0.203	w = 1/[σ2(Fo2) + (0.0863P)2 + 0.4481P] where P = (Fo2 + 2Fc2)/3
S = 1.17	(Δ/σ)max < 0.001
1446 reflections	Δρmax = 0.38 e Å−3
96 parameters	Δρmin = −0.35 e Å−3
1 restraint	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.011 (4)

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	0.9509 (2)	0.2500	1.1853 (3)	0.0603 (8)
H11	0.9026	0.2500	1.2416	0.072*
C2	1.0499 (3)	0.2500	1.2128 (4)	0.0731 (10)
H2	1.0689	0.2500	1.2880	0.088*
C3	1.1212 (2)	0.2500	1.1306 (4)	0.0723 (11)
H3	1.1883	0.2500	1.1510	0.087*
C4	1.0962 (2)	0.2500	1.0186 (4)	0.0641 (9)
H4	1.1454	0.2500	0.9633	0.077*
C5	0.99369 (19)	0.2500	0.9893 (2)	0.0449 (6)
C6	0.92245 (18)	0.2500	1.0730 (2)	0.0440 (6)
C7	0.79331 (18)	0.2500	0.9352 (2)	0.0427 (6)
C8	0.8664 (2)	0.2500	0.8500 (2)	0.0481 (6)
C9	0.8419 (3)	0.2500	0.7287 (3)	0.0705 (9)
H9A	0.9023	0.2500	0.6845	0.080*
H9B	0.8034	0.1355	0.7099	0.080*
C10	0.6836 (2)	0.2500	0.9063 (3)	0.0551 (7)
H10	0.6798	0.2500	0.8240	0.066*
C11	0.63084 (17)	0.0655 (4)	0.9452 (2)	0.0777 (8)
H11A	0.6657	−0.0468	0.9169	0.117*
H11B	0.5636	0.0652	0.9173	0.117*
H11C	0.6299	0.0615	1.0259	0.117*
N1	0.82094 (15)	0.2500	1.04424 (19)	0.0445 (6)
N2	0.96482 (17)	0.2500	0.8772 (2)	0.0513 (6)
O1	0.75580 (15)	0.2500	1.12490 (18)	0.0681 (7)
O2	1.03357 (18)	0.2500	0.8002 (2)	0.0809 (8)

	U11	U22	U33	U12	U13	U23
C1	0.0617 (17)	0.0652 (18)	0.0539 (18)	0.000	−0.0125 (14)	0.000
C2	0.067 (2)	0.066 (2)	0.085 (3)	0.000	−0.0309 (19)	0.000
C3	0.0494 (16)	0.0531 (16)	0.114 (3)	0.000	−0.0284 (19)	0.000
C4	0.0403 (13)	0.0433 (14)	0.109 (3)	0.000	0.0089 (16)	0.000
C5	0.0405 (12)	0.0326 (11)	0.0616 (17)	0.000	0.0047 (11)	0.000
C6	0.0389 (12)	0.0377 (12)	0.0553 (15)	0.000	−0.0038 (11)	0.000
C7	0.0408 (12)	0.0438 (12)	0.0434 (14)	0.000	−0.0006 (10)	0.000
C8	0.0557 (14)	0.0409 (12)	0.0477 (15)	0.000	0.0076 (12)	0.000
C9	0.084 (2)	0.081 (2)	0.0466 (17)	0.000	0.0075 (16)	0.000
C10	0.0409 (13)	0.0706 (18)	0.0537 (17)	0.000	−0.0040 (12)	0.000
C11	0.0525 (11)	0.0818 (17)	0.099 (2)	−0.0170 (11)	−0.0097 (12)	0.0027 (15)
N1	0.0368 (10)	0.0509 (12)	0.0457 (12)	0.000	0.0050 (9)	0.000
N2	0.0485 (12)	0.0406 (11)	0.0648 (15)	0.000	0.0196 (11)	0.000
O1	0.0461 (10)	0.1067 (18)	0.0516 (12)	0.000	0.0126 (9)	0.000
O2	0.0716 (15)	0.0876 (17)	0.0836 (18)	0.000	0.0422 (13)	0.000

C1—C2	1.365 (4)	C7—C10	1.508 (4)
C1—C6	1.389 (4)	C8—N2	1.357 (4)
C1—H11	0.9300	C8—C9	1.479 (4)
C2—C3	1.366 (6)	C9—H9A	0.964 (4)
C2—H2	0.9300	C9—H9B	0.964 (2)
C3—C4	1.373 (5)	C10—C11i	1.519 (3)
C3—H3	0.9300	C10—C11	1.519 (3)
C4—C5	1.416 (4)	C10—H10	0.9800
C4—H4	0.9300	C11—H11A	0.9600
C5—C6	1.378 (4)	C11—H11B	0.9600
C5—N2	1.387 (4)	C11—H11C	0.9600
C6—N1	1.401 (3)	N1—O1	1.296 (3)
C7—N1	1.348 (3)	N2—O2	1.298 (3)
C7—C8	1.409 (4)
C2—C1—C6	119.7 (3)	C7—C8—C9	123.1 (3)
C2—C1—H11	120.1	C8—C9—H9A	110.2 (3)
C6—C1—H11	120.1	C8—C9—H9B	110.1 (2)
C1—C2—C3	120.5 (3)	H9A—C9—H9B	108.8 (2)
C1—C2—H2	119.7	C7—C10—C11i	112.56 (16)
C3—C2—H2	119.7	C7—C10—C11	112.56 (16)
C2—C3—C4	121.5 (3)	C11i—C10—C11	112.5 (3)
C2—C3—H3	119.2	C7—C10—H10	106.2
C4—C3—H3	119.2	C11i—C10—H10	106.2
C3—C4—C5	118.4 (3)	C11—C10—H10	106.2
C3—C4—H4	120.8	C10—C11—H11A	109.5
C5—C4—H4	120.8	C10—C11—H11B	109.5
C6—C5—N2	120.0 (2)	H11A—C11—H11B	109.5
C6—C5—C4	119.6 (3)	C10—C11—H11C	109.5
N2—C5—C4	120.4 (3)	H11A—C11—H11C	109.5
C5—C6—C1	120.3 (3)	H11B—C11—H11C	109.5
C5—C6—N1	119.7 (3)	O1—N1—C7	121.8 (2)
C1—C6—N1	120.0 (3)	O1—N1—C6	118.2 (2)
N1—C7—C8	120.0 (2)	C7—N1—C6	120.0 (2)
N1—C7—C10	119.1 (2)	O2—N2—C8	121.4 (3)
C8—C7—C10	120.9 (3)	O2—N2—C5	118.7 (2)
N2—C8—C7	120.2 (3)	C8—N2—C5	120.0 (2)
N2—C8—C9	116.6 (3)
C6—C1—C2—C3	0.000 (2)	C8—C7—C10—C11	115.8 (2)
C1—C2—C3—C4	0.000 (2)	C8—C7—N1—O1	180.0
C2—C3—C4—C5	0.000 (1)	C10—C7—N1—O1	0.0
C3—C4—C5—C6	0.000 (1)	C8—C7—N1—C6	0.0
C3—C4—C5—N2	180.000 (1)	C10—C7—N1—C6	180.0
N2—C5—C6—C1	180.0	C5—C6—N1—O1	180.0
C4—C5—C6—C1	0.000 (1)	C1—C6—N1—O1	0.0
N2—C5—C6—N1	0.0	C5—C6—N1—C7	0.0
C4—C5—C6—N1	180.0	C1—C6—N1—C7	180.0
C2—C1—C6—C5	0.000 (1)	C7—C8—N2—O2	180.0
C2—C1—C6—N1	180.0	C9—C8—N2—O2	0.0
N1—C7—C8—N2	0.0	C7—C8—N2—C5	0.0
C10—C7—C8—N2	180.0	C9—C8—N2—C5	180.0
N1—C7—C8—C9	180.0	C6—C5—N2—O2	180.0
C10—C7—C8—C9	0.0	C4—C5—N2—O2	0.0
N1—C7—C10—C11i	64.2 (2)	C6—C5—N2—C8	0.0
C8—C7—C10—C11i	−115.8 (2)	C4—C5—N2—C8	180.0
N1—C7—C10—C11	−64.2 (2)