4-Methyl-3-nitro­pyridin-2-amine

Abstract

In the title compound, C₆H₇N₃O₂, the dihedral angle between the nitro group and the pyridine ring is 15.5 (3)° and an intra­molecular N—H⋯O hydrogen bond occurs. In the crystal, inversion dimers linked by two N—H⋯N hydrogen bonds occur, resulting in R ₂ ²(8) rings. The packing is stabilized by aromatic π–π stacking [centroid–centroid distance = 3.5666 (15) Å] and a short N—O⋯π contact is seen.

Related literature

For a related structure, see: Kvick & Noordik (1977 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

• C₆H₇N₃O₂

• M _r = 153.15

• Monoclinic,

• a = 7.3776 (6) Å

• b = 12.8673 (11) Å

• c = 7.3884 (6) Å

• β = 104.364 (4)°

• V = 679.45 (10) ų

• Z = 4

• Mo Kα radiation

• μ = 0.12 mm⁻¹

• T = 296 K

• 0.25 × 0.10 × 0.08 mm

Data collection

• Bruker Kappa APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.985, T _max = 0.992

• 7483 measured reflections

• 1677 independent reflections

• 759 reflections with I > 2σ(I)

• R _int = 0.055

Refinement

• R[F ² > 2σ(F ²)] = 0.056

• wR(F ²) = 0.173

• S = 1.00

• 1677 reflections

• 107 parameters

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

• Δρ_max = 0.39 e Å⁻³

• Δρ_min = −0.32 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; 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.

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
N2—H2A⋯N1i	0.88 (3)	2.17 (4)	3.045 (4)	174 (3)
N2—H2B⋯O1	0.85 (3)	2.01 (3)	2.612 (4)	127 (2)
N3—O2⋯Cg1ii	1.20 (1)	3.27 (1)	3.681 (12)	100 (1)

Symmetry codes: (i) ; (ii) . Cg1 is the centroid of the pyridine ring.

supplementary crystallographic information

Comment

Pyridines form a very important class of heterocyclic compounds. In it are included various vitamins, enzymes, pharmaceuticals, dyes, agrochemicals and other products. The title compound (I), (Fig. 1) is nitro substituted 2-Amino-4-methylpyridine.

The crystal structure of (II) 2-Amino-4-methylpyridine (Kvick & Noordik, 1977) has been reported. In (I), the pyridine ring A (C1—C5/N1) is planar with Rms deviation of 0.0135 Å. The amino N-atom and the methyl C-atom deviates from the plane of ring A by -0.0551 (37) Å and -0.044 (4) Å, respectively. The dihedral angle between ring A and nitro group B (O1/N3/O2) is 15.53 (27)°. The title compound consists of dimers due to inversion related intermolecular H-bonds of N–H···N type forming ring motifs R₂²(8) (Bernstein et al., 1995). The interamoleculr H-bond of N–H···O type completes R₁¹(6) ring motif (Fig. 2). The molecules are stabilized due to π–π-interactions with centroid to centroid distance of 3.5666 (15) Å [CgA···CgAⁱ: symmetry code i = 2 - x, -y, -z] and N–O···π interactions (Table 1).

Experimental

2-Amino-4-picoline (1.1 g, 0.01 mol) was dissolved in 10 ml of concentrated nitric and sulfuric acid (1:1) and cooled to 278 K. The mixture was left overnight and the resultant nitramino product was further treated with 5 ml of conc. sulfuric acid at room temperature for 3 h and poured over 250 g of crushed ice. The precipitates obtained were collected by filtration and subjected to steam distillation. The title compound was obtained as yellow needles of (I) on cooling the distillate to room temperature.

Refinement

The coordinates of the H-atoms of the NH₂ group were located in a difference map and refined. The other H-atoms were positioned geometrically (C—H = 0.93—0.96 Å) and refined as riding with U_iso(H) = 1.2U_eq(C, N).

Figures

Fig. 1.

View of (I) with displacement ellipsoids drawn at the 50% probability level. H-atoms are shown by small spheres of arbitrary radii. Intermolecular H-bond is shown by dotted lines.

Fig. 2.

The partial packing of (I), which shows that molecules form dimers.

Crystal data

C6H7N3O2	F(000) = 320
Mr = 153.15	Dx = 1.497 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1677 reflections
a = 7.3776 (6) Å	θ = 3.2–28.3°
b = 12.8673 (11) Å	µ = 0.12 mm−1
c = 7.3884 (6) Å	T = 296 K
β = 104.364 (4)°	Needle, yellow
V = 679.45 (10) Å3	0.25 × 0.10 × 0.08 mm
Z = 4

Data collection

Bruker Kappa APEXII CCD diffractometer	1677 independent reflections
Radiation source: fine-focus sealed tube	759 reflections with I > 2σ(I)
graphite	Rint = 0.055
Detector resolution: 7.40 pixels mm-1	θmax = 28.3°, θmin = 3.2°
ω scans	h = −9→9
Absorption correction: multi-scan (SADABS; Bruker, 2005)	k = −17→17
Tmin = 0.985, Tmax = 0.992	l = −9→9
7483 measured reflections

Refinement

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)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.173	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	w = 1/[σ2(Fo2) + (0.0745P)2 + 0.0769P] where P = (Fo2 + 2Fc2)/3
1677 reflections	(Δ/σ)max < 0.001
107 parameters	Δρmax = 0.39 e Å−3
0 restraints	Δρmin = −0.31 e Å−3

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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	0.9915 (3)	−0.20091 (18)	0.2978 (3)	0.0860 (10)
O2	1.2249 (3)	−0.11801 (19)	0.4483 (4)	0.0904 (10)
N1	0.7197 (3)	0.06783 (18)	0.0831 (3)	0.0426 (8)
N2	0.6845 (4)	−0.1039 (2)	0.1310 (3)	0.0529 (9)
N3	1.0759 (3)	−0.11908 (19)	0.3358 (3)	0.0475 (9)
C1	0.8004 (4)	−0.0221 (2)	0.1552 (3)	0.0386 (8)
C2	0.9935 (3)	−0.0238 (2)	0.2507 (3)	0.0378 (9)
C3	1.1041 (3)	0.0656 (2)	0.2608 (3)	0.0405 (9)
C4	1.0135 (4)	0.1542 (2)	0.1803 (4)	0.0480 (10)
C5	0.8246 (4)	0.1511 (2)	0.0979 (4)	0.0472 (10)
C6	1.3108 (4)	0.0719 (3)	0.3480 (4)	0.0555 (10)
H2A	0.570 (5)	−0.089 (2)	0.066 (4)	0.0635*
H2B	0.730 (4)	−0.164 (2)	0.156 (4)	0.0635*
H4	1.07986	0.21582	0.18170	0.0576*
H5	0.76702	0.21275	0.04899	0.0566*
H6A	1.35738	0.13785	0.31888	0.0666*
H6B	1.37365	0.01708	0.29973	0.0666*
H6C	1.33334	0.06475	0.48107	0.0666*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0667 (16)	0.0497 (16)	0.127 (2)	−0.0025 (12)	−0.0035 (14)	0.0240 (14)
O2	0.0609 (15)	0.0759 (19)	0.110 (2)	0.0105 (13)	−0.0247 (14)	0.0200 (14)
N1	0.0373 (12)	0.0424 (14)	0.0475 (13)	0.0041 (11)	0.0096 (10)	−0.0006 (11)
N2	0.0399 (13)	0.0506 (17)	0.0639 (16)	−0.0020 (13)	0.0048 (12)	0.0097 (14)
N3	0.0416 (14)	0.0502 (17)	0.0506 (14)	0.0091 (12)	0.0110 (12)	0.0076 (12)
C1	0.0355 (14)	0.0427 (16)	0.0394 (14)	0.0019 (13)	0.0126 (11)	−0.0016 (12)
C2	0.0356 (15)	0.0404 (16)	0.0378 (14)	0.0070 (12)	0.0101 (11)	0.0004 (12)
C3	0.0361 (14)	0.0500 (18)	0.0354 (14)	0.0038 (13)	0.0090 (11)	−0.0046 (12)
C4	0.0493 (18)	0.0399 (17)	0.0547 (17)	−0.0042 (14)	0.0126 (14)	−0.0032 (14)
C5	0.0495 (18)	0.0421 (17)	0.0492 (16)	0.0105 (14)	0.0110 (13)	−0.0001 (13)
C6	0.0391 (16)	0.066 (2)	0.0589 (18)	−0.0051 (14)	0.0077 (13)	−0.0058 (16)

Geometric parameters (Å, °)

O1—N3	1.220 (3)	C2—C3	1.402 (4)
O2—N3	1.203 (3)	C3—C4	1.380 (4)
N1—C1	1.349 (3)	C3—C6	1.503 (4)
N1—C5	1.310 (4)	C4—C5	1.376 (4)
N2—C1	1.340 (4)	C4—H4	0.9300
N3—C2	1.442 (3)	C5—H5	0.9300
N2—H2B	0.85 (3)	C6—H6A	0.9600
N2—H2A	0.88 (3)	C6—H6B	0.9600
C1—C2	1.425 (4)	C6—H6C	0.9600
C1—N1—C5	118.4 (2)	C2—C3—C4	116.2 (2)
O1—N3—O2	119.7 (2)	C4—C3—C6	118.2 (3)
O1—N3—C2	119.9 (2)	C3—C4—C5	119.7 (2)
O2—N3—C2	120.4 (2)	N1—C5—C4	125.0 (3)
H2A—N2—H2B	126 (3)	C3—C4—H4	120.00
C1—N2—H2A	113.3 (18)	C5—C4—H4	120.00
C1—N2—H2B	119 (2)	N1—C5—H5	118.00
N1—C1—N2	114.6 (3)	C4—C5—H5	118.00
N1—C1—C2	119.9 (2)	C3—C6—H6A	109.00
N2—C1—C2	125.5 (2)	C3—C6—H6B	109.00
N3—C2—C1	119.4 (2)	C3—C6—H6C	109.00
N3—C2—C3	119.9 (2)	H6A—C6—H6B	109.00
C1—C2—C3	120.8 (2)	H6A—C6—H6C	109.00
C2—C3—C6	125.6 (2)	H6B—C6—H6C	109.00
C5—N1—C1—N2	−178.7 (2)	N2—C1—C2—N3	−2.1 (4)
C5—N1—C1—C2	2.3 (4)	N2—C1—C2—C3	177.2 (2)
C1—N1—C5—C4	0.8 (4)	N3—C2—C3—C4	−178.3 (2)
O1—N3—C2—C1	13.3 (3)	N3—C2—C3—C6	2.8 (4)
O1—N3—C2—C3	−166.0 (2)	C1—C2—C3—C4	2.4 (3)
O2—N3—C2—C1	−164.5 (2)	C1—C2—C3—C6	−176.4 (2)
O2—N3—C2—C3	16.2 (4)	C2—C3—C4—C5	0.5 (4)
N1—C1—C2—N3	176.7 (2)	C6—C3—C4—C5	179.5 (3)
N1—C1—C2—C3	−4.0 (3)	C3—C4—C5—N1	−2.3 (5)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···N1i	0.88 (3)	2.17 (4)	3.045 (4)	174 (3)
N2—H2B···O1	0.85 (3)	2.01 (3)	2.612 (4)	127 (2)
N3—O2···Cg1ii	1.203 (3)	3.2743 (3)	3.681 (12)	100.16 (17)

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