2-Chloro-4-nitro­pyridine N-oxide

Shafer, S.K.; Lynch, W.E.; Padgett, C.W.

doi:10.1107/S2414314618000160

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 3| Part 1| January 2018| x180016

https://doi.org/10.1107/S2414314618000160

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2-Chloro-4-nitropyridine N-oxide

Sarah K Shafer,^a Will E Lynch ^a and Clifford W Padgett ^a ^*

^aGeorgia Southern University, 11935 Abercorn St. Savanah GA 31419, USA
^*Correspondence e-mail: clifford.padgett@armstrong.edu

Edited by E. R. T. Tiekink, Sunway University, Malaysia (Received 17 December 2017; accepted 3 January 2018; online 9 January 2018)

In the title compound, C₅H₃ClN₂O₃ (systematic name: 2-chloro-4-nitropyridin-1-ium-1-olate), the nitro group is essentially coplanar with the aromatic ring, with a twist angle of 6.48 (8)°. The molecular packing exhibits a herringbone pattern with the zigzag running along the b axis; here, there are no short contacts, hydrogen bonds, or π–π interactions.

Keywords: crystal structure; pyridine N-oxide; herringbone pattern.

CCDC reference: 1814493

Structure description

Pyridine N-oxide and related compounds have garnered much interest in organic chemistry since their preparation was first reported by Meisenheimer (1926 ). A number of recent publications have highlighted their utility in organic transformations such as reactions with Grignard reagents (Andersson et al., 2011 ), aromatic ring substitutions (Shibata & Takano, 2015 ) and aromatic coupling reactions (Wang & Zhang, 2015 ). Further, numerous uses in pharmaceutical applications have been realised throughout the years, such as the recent report of uses as an emerging class of therapeutic agents, including thrombin as a potential clotting inhibitor drug (Mfuh & Larionov, 2015 ).

In the title compound (Fig. 1), the nitro group is essentially coplanar with the aromatic ring, with a twist angle of 6.48 (8)°. The crystal structure (Fig. 2) exhibits a herringbone pattern with the zigzag running along the b axis. The herringbone layer-to-layer distance is 2.947 (4) Å with a shift of 5.155 (5) Å. Neighboring molecules of the herringbone are tilted at a 47.08 (10)° (ring-to-ring) angle to each other. The chloro group in one of herringbone chains points to the chloro group in the neighboring one, with a Cl⋯Cl intermolecular distance of 3.708 (2) Å. In the bends of the chains, the N-oxide aligns with the nitro group with an O⋯O distance of 2.922 (3) Å. There are no other short contacts, hydrogen bonds, or π–π interactions.

Figure 1
A view of the molecular structure of the title compound, with the atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2
Molecular packing diagram of title compound viewed along the c axis.

This structure is similar to the previously reported structure of 2,6-dichloro-4-nitropyridine N-oxide (Prichard et al., 2015 ).

Synthesis and crystallization

2-Chloro-4-nitropyridine N-oxide was purchased from Sigma–Aldrich and 0.10 g was dissolved in approximately 50 ml of chloroform. Diffraction-quality crystals were obtained by slow evaporation of the solvent.

Refinement

Crystal data, data collection, and structure refinement details are summarized in Table 1.

Table 1
Experimental details

Crystal data
Chemical formula	C₅H₃ClN₂O₃
M_r	174.54
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	176
a, b, c (Å)	5.9238 (14), 9.735 (2), 22.444 (8)
V (Å³)	1294.3 (5)
Z	8
Radiation type	Mo Kα
μ (mm⁻¹)	0.54
Crystal size (mm)	0.34 × 0.18 × 0.08

Data collection
Diffractometer	Rigaku XtalLab mini CCD
Absorption correction	Multi-scan (REQAB;Rigaku, 1998 )
T_min, T_max	0.741, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	11029, 1485, 1088
R_int	0.111
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.050, 0.132, 1.06
No. of reflections	1484
No. of parameters	100
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.33, −0.33
Computer programs: CrystalClear (Rigaku, 2009 ), SHELXT (Sheldrick, 2015b ), SHELXL (Sheldrick, 2015a ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 1814493

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314618000160/tk4042sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314618000160/tk4042Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314618000160/tk4042Isup3.cml

checkCIF report

Computing details top

Data collection: CrystalClear (Rigaku, 2009); cell refinement: CrystalClear (Rigaku, 2009); data reduction: CrystalClear (Rigaku, 2009); program(s) used to solve structure: SHELXT (Sheldrick, 2015b); program(s) used to refine structure: SHELXL (Sheldrick, 2015a); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

2-Chloro-4-nitropyridine N-oxide top

Crystal data top

C₅H₃ClN₂O₃	D_x = 1.791 Mg m⁻³
M_r = 174.54	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbca	Cell parameters from 2672 reflections
a = 5.9238 (14) Å	θ = 2.1–27.5°
b = 9.735 (2) Å	µ = 0.54 mm⁻¹
c = 22.444 (8) Å	T = 176 K
V = 1294.3 (5) Å³	Prism, colorless
Z = 8	0.34 × 0.18 × 0.08 mm
F(000) = 704

Data collection top

Rigaku XtalLab mini CCD diffractometer	1088 reflections with I > 2σ(I)
ω scans	R_int = 0.111
Absorption correction: multi-scan (REQAB;Rigaku, 1998)	θ_max = 27.5°, θ_min = 1.8°
T_min = 0.741, T_max = 1.000	h = −7→7
11029 measured reflections	k = −12→12
1485 independent reflections	l = −28→28

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.050	H-atom parameters constrained
wR(F²) = 0.132	w = 1/[σ²(F_o²) + (0.056P)² + 0.245P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max < 0.001
1484 reflections	Δρ_max = 0.33 e Å⁻³
100 parameters	Δρ_min = −0.33 e Å⁻³
0 restraints

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Carbon-bound H-atoms were placed in calculated positions (C—H = 0.95 Å) and were included in the refinement in the riding model approximation,with U_iso(H) set to 1.2U_equiv(C)

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

	x	y	z	U_iso*/U_eq
Cl1	0.84970 (12)	0.41241 (8)	0.70078 (3)	0.0328 (3)
O1	1.0061 (3)	0.4471 (2)	0.58347 (8)	0.0308 (5)
O2	0.1310 (3)	0.7204 (2)	0.67343 (9)	0.0394 (6)
O3	0.1031 (3)	0.7656 (2)	0.57923 (8)	0.0327 (5)
N1	0.8139 (3)	0.5062 (2)	0.59237 (9)	0.0230 (5)
N2	0.2001 (4)	0.7138 (2)	0.62205 (9)	0.0272 (5)
C1	0.7126 (4)	0.5030 (3)	0.64730 (10)	0.0241 (6)
C2	0.5117 (4)	0.5703 (3)	0.65747 (11)	0.0249 (6)
H2	0.445346	0.569168	0.695020	0.030*
C3	0.4116 (4)	0.6391 (3)	0.61119 (11)	0.0244 (6)
C4	0.5083 (4)	0.6418 (3)	0.55541 (11)	0.0252 (6)
H4	0.438517	0.688058	0.524175	0.030*
C5	0.7094 (4)	0.5752 (3)	0.54681 (11)	0.0257 (6)
H5	0.776304	0.576716	0.509329	0.031*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0334 (4)	0.0350 (4)	0.0301 (4)	0.0086 (3)	−0.0052 (3)	0.0017 (3)
O1	0.0223 (10)	0.0284 (11)	0.0418 (12)	0.0070 (9)	0.0068 (8)	−0.0018 (8)
O2	0.0331 (12)	0.0453 (14)	0.0397 (12)	0.0094 (10)	0.0090 (9)	−0.0013 (10)
O3	0.0255 (10)	0.0300 (11)	0.0425 (12)	0.0013 (9)	−0.0069 (8)	0.0048 (9)
N1	0.0210 (12)	0.0174 (11)	0.0307 (11)	−0.0014 (10)	0.0032 (8)	−0.0024 (9)
N2	0.0209 (12)	0.0248 (12)	0.0360 (13)	−0.0017 (10)	0.0012 (9)	−0.0006 (10)
C1	0.0261 (14)	0.0212 (13)	0.0249 (12)	−0.0009 (12)	−0.0037 (10)	−0.0013 (10)
C2	0.0235 (14)	0.0258 (14)	0.0255 (13)	−0.0027 (12)	0.0021 (10)	−0.0012 (10)
C3	0.0198 (13)	0.0225 (13)	0.0308 (14)	−0.0016 (11)	−0.0006 (11)	−0.0030 (10)
C4	0.0253 (14)	0.0247 (14)	0.0257 (14)	−0.0017 (11)	−0.0033 (10)	0.0017 (10)
C5	0.0279 (14)	0.0269 (14)	0.0224 (13)	−0.0050 (12)	0.0026 (10)	0.0003 (11)

Geometric parameters (Å, º) top

Cl1—C1	1.697 (3)	C1—C2	1.378 (4)
O1—N1	1.291 (3)	C2—H2	0.9300
O2—N2	1.225 (3)	C2—C3	1.371 (4)
O3—N2	1.228 (3)	C3—C4	1.377 (4)
N1—C1	1.372 (4)	C4—H4	0.9300
N1—C5	1.371 (3)	C4—C5	1.370 (4)
N2—C3	1.469 (4)	C5—H5	0.9300

O1—N1—C1	121.0 (2)	C3—C2—H2	120.6
O1—N1—C5	120.1 (2)	C2—C3—N2	119.0 (2)
C5—N1—C1	118.9 (2)	C2—C3—C4	121.2 (3)
O2—N2—O3	124.0 (3)	C4—C3—N2	119.7 (2)
O2—N2—C3	117.9 (2)	C3—C4—H4	120.6
O3—N2—C3	118.2 (2)	C5—C4—C3	118.7 (2)
N1—C1—Cl1	116.0 (2)	C5—C4—H4	120.6
N1—C1—C2	121.1 (2)	N1—C5—H5	119.4
C2—C1—Cl1	122.9 (2)	C4—C5—N1	121.3 (2)
C1—C2—H2	120.6	C4—C5—H5	119.4
C3—C2—C1	118.7 (2)

Funding information

The authors acknowledge financial support from Armstrong State University.

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