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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoIUCrDATA
ISSN: 2414-3146
Volume 1| Part 4| April 2016| x160567
doi:10.1107/S2414314616005678

1-Ethyl-5-nitro-1H-indazole

Mohammed Boulhaoua,a* Mohamed El Hafi,a Mohammed Benchidmi,a El Mokhtar Essassia and Joel T. Magueb

aLaboratoire de Chimie Organique Hétérocyclique, URAC 21, Pôle de Compétence Pharmacochimie, Av. Ibn Battouta, BP 1014, Faculté des Sciences, Université Mohammed V, Rabat, Morocco, and bDepartment of Chemistry, Tulane University, New Orleans, LA 70118, USA
*Correspondence e-mail: mboulhaoua@gmail.com

Edited by E. R. T. Tiekink, Sunway University, Malaysia (Received 15 March 2016; accepted 5 April 2016; online 12 April 2016)

In the title mol­ecule, C9H9N3O2, the nitro substituent is twisted by 4.0 (2)° out of the plane of the indazolyl moiety; the ethyl group is perpendicular to the indazolyl plane, with the N—N—C—C torsion angle being 101.4 (2)°. In the mol­ecular packing, C—H⋯O hydrogen bonds lead to supra­molecular chains along [001]. Globally, mol­ecules assemble into layers in the bc plane. π–π inter­actions between five- and six-membered rings consolidate the three-dimensional packing [inter-centroid distance = 3.591 (1) Å]. The sample was refined as an inversion twin.

CCDC reference: 1472479

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

As a continuation of our research work devoted to the development of N-substituted indazoles (El Brahmi et al., 2012[El Brahmi, N., Benchidmi, M., Essassi, E. M., Ladeira, S. & El Ammari, L. (2012). Acta Cryst. E68, o3368.]; Boulhaoua et al., 2015[Boulhaoua, M., Benchidmi, M., Essassi, E. M., Saadi, M. & El Ammari, L. (2015). Acta Cryst. E71, o780-o781.]), we have studied the action of bromo­ethane towards 5-nitro-1H-indazole under phase-transfer catalysis conditions using tetra-n-butyl­ammonium iodide (TBAI) as catalyst and potassium carbonate as base. This readily leads to the title compound (Fig. 1[link]) in good yield. The nitro substituent is twisted 4.0 (2)° out of the plane of the indazolyl moiety while the ethyl group is twisted well out of that plane and away from N2 as indicated by the N2—N1—C8—C9 torsion angle of 101.4 (2)°. The mol­ecules pack in layers in the bc plane being partially assembled through C3—H3⋯O1(−x + [{3\over 2}], −y + 2, z + [{1\over 2}]) hydrogen bonds (Table 1[link] and Fig. 2[link]). The layers inter­act via offset π–π-stacking between the C2–C7 ring in one layer and the (C1,C2,N1,N2,C7) ring (related by the symmetry operation [{1\over 2}] + x, [{3\over 2}] − y, 1 − z) in the next. The distance between the ring centroids is 3.591 (1) Å, the dihedral angle between the planes is 6.82 (9)° and the `slippage' is 1.08 Å.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
C3—H3⋯O1i 0.95 2.38 3.237 (2) 150
Symmetry code: (i) [-x+{\script{3\over 2}}, -y+2, z+{\script{1\over 2}}].
[Figure 1]
Figure 1
The title mol­ecule with labelling scheme and 50% probability ellipsoids.
[Figure 2]
Figure 2
Packing viewed along the a axis with inter­molecular C—H⋯O hydrogen bonds shown as dashed lines.

Synthesis and crystallization

To a solution of 5-nitro-1H-indazole (0.5 g, 3 mmol) in DMF (15 ml) was added bromo­ethane (0.22 ml, 3 mmol), potassium carbonate (0.83 g, 6 mmol) and a catalytic qu­antity of tetra-n-butyl­ammonium iodide. The mixture was stirred at room temperature for 48 h. The solution was filtered and the solvent removed under reduced pressure. The solid product was purified by recrystallization from ethanol to afford the title compound as pale-pink crystals (yield: 70%; m.p. = 392–394 K).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. The sample was refined as an inversion twin.

Table 2
Experimental details

Crystal data
Chemical formula C9H9N3O2
Mr 191.19
Crystal system, space group Orthorhombic, P212121
Temperature (K) 150
a, b, c (Å) 6.7563 (1), 11.2307 (2), 11.7323 (3)
V (Å3) 890.22 (3)
Z 4
Radiation type Cu Kα
μ (mm−1) 0.87
Crystal size (mm) 0.17 × 0.13 × 0.06
 
Data collection
Diffractometer Bruker D8 VENTURE PHOTON 100 CMOS
Absorption correction Multi-scan (SADABS; Bruker, 2016[Bruker (2016). APEX3, SAINT and SADABS. Bruker AXS, Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.87, 0.95
No. of measured, independent and observed [I > 2σ(I)] reflections 6805, 1751, 1689
Rint 0.029
(sin θ/λ)max (Å−1) 0.618
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.032, 0.083, 1.14
No. of reflections 1751
No. of parameters 129
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.17, −0.21
Absolute structure Refined as an inversion twin
Absolute structure parameter 0.3 (3)
Computer programs: APEX3 (Bruker, 2016[Bruker (2016). APEX3, SAINT and SADABS. Bruker AXS, Inc., Madison, Wisconsin, USA.]), SAINT (Bruker, 2016[Bruker (2016). APEX3, SAINT and SADABS. Bruker AXS, Inc., Madison, Wisconsin, USA.]), SAINT (Bruker, 2016[Bruker (2016). APEX3, SAINT and SADABS. Bruker AXS, Inc., Madison, Wisconsin, USA.]), SHELXT (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL2014 (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]), DIAMOND (Brandenburg & Putz, 2012[Brandenburg, K. & Putz, H. (2012). DIAMOND. Crystal Impact GbR, Bonn, Germany.]), SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).

Structural data

CCDC reference: 1472479

Crystal structure: contains datablocks global, I. DOI: 10.1107/S2414314616005678/tk4008sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2414314616005678/tk4008Isup2.hkl

Supporting information file. DOI: 10.1107/S2414314616005678/tk4008Isup3.cdx

Supporting information file. DOI: 10.1107/S2414314616005678/tk4008Isup4.cml

checkCIF report


Experimental top

To a solution of 5-nitro-1H-indazole (0.5 g, 3 mmol) in DMF (15 ml) was added bromoethane (0.22 ml, 3 mmol), potassium carbonate (0.83 g, 6 mmol) and a catalytic quantity of tetra-n-butylammonium iodide. The mixture was stirred at room temperature for 48 h. The solution was filtered and the solvent removed under reduced pressure. The solid product was purified by recrystallization from ethanol to afford the title compound as pale-pink crystals (yield: 70%; m.p. = 392–394 K).

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 2. The sample was refined as an inversion twin.

Structure description top

As a continuation of our research work devoted to the development of N-substituted indazoles (El Brahmi et al., 2012; Boulhaoua et al., 2015), we have studied the action of bromoethane towards 5-nitro-1H-indazole under phase-transfer catalysis conditions using tetra-n-butylammonium iodide (TBAI) as catalyst and potassium carbonate as base. This readily leads to the title compound (Fig. 1) in good yield. The nitro substituent is twisted 4.0 (2)° out of the plane of the indazolyl moiety while the ethyl group is twisted well out of that plane and away from N2 as indicated by the N2—N1—C8—C9 torsion angle of 101.4 (2)°. The molecules pack in layers in the bc plane being partially assembled through C3—H3···O1(-x + 3/2, -y + 2, z + 1/2) hydrogen bonds (Table 1 and Fig. 2). The layers interact via offset π–π-stacking between the C2–C7 ring in one layer and the (C1,C2,N1,N2,C7) ring (related by the symmetry operation 1/2 + x, 3/2 - y, 1 - z) in the next. The distance between the ring centroids is 3.591 (1) Å, the dihedral angle between the planes is 6.82 (9)° and the `slippage' is 1.08 Å.

Computing details top

Data collection: APEX3 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg & Putz, 2012); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The title molecule with labelling scheme and 50% probability ellipsoids.
[Figure 2] Fig. 2. Packing viewed along the a axis with intermolecular C—H···O hydrogen bonds shown as dashed lines.
1-Ethyl-5-nitro-1H-indazole top
Crystal data top
C9H9N3O2Dx = 1.427 Mg m−3
Mr = 191.19Cu Kα radiation, λ = 1.54178 Å
Orthorhombic, P212121Cell parameters from 5857 reflections
a = 6.7563 (1) Åθ = 5.5–72.3°
b = 11.2307 (2) ŵ = 0.87 mm−1
c = 11.7323 (3) ÅT = 150 K
V = 890.22 (3) Å3Thick plate, pale-pink
Z = 40.17 × 0.13 × 0.06 mm
F(000) = 400
Data collection top
Bruker D8 VENTURE PHOTON 100 CMOS
diffractometer		1751 independent reflections
Radiation source: INCOATEC IµS micro–focus source1689 reflections with I > 2σ(I)
Mirror monochromatorRint = 0.029
Detector resolution: 10.4167 pixels mm-1θmax = 72.2°, θmin = 5.5°
ω scansh = −7→8
Absorption correction: multi-scan
(SADABS; Bruker, 2016)		k = −13→13
Tmin = 0.87, Tmax = 0.95l = −14→13
6805 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.032H-atom parameters constrained
wR(F2) = 0.083 w = 1/[σ2(Fo2) + (0.0501P)2 + 0.0784P]
where P = (Fo2 + 2Fc2)/3
S = 1.14(Δ/σ)max < 0.001
1751 reflectionsΔρmax = 0.17 e Å−3
129 parametersΔρmin = −0.21 e Å−3
0 restraintsAbsolute structure: Refined as an inversion twin
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.3 (3)
Crystal data top
C9H9N3O2V = 890.22 (3) Å3
Mr = 191.19Z = 4
Orthorhombic, P212121Cu Kα radiation
a = 6.7563 (1) ŵ = 0.87 mm−1
b = 11.2307 (2) ÅT = 150 K
c = 11.7323 (3) Å0.17 × 0.13 × 0.06 mm
Data collection top
Bruker D8 VENTURE PHOTON 100 CMOS
diffractometer		1751 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2016)		1689 reflections with I > 2σ(I)
Tmin = 0.87, Tmax = 0.95Rint = 0.029
6805 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.032H-atom parameters constrained
wR(F2) = 0.083Δρmax = 0.17 e Å−3
S = 1.14Δρmin = −0.21 e Å−3
1751 reflectionsAbsolute structure: Refined as an inversion twin
129 parametersAbsolute structure parameter: 0.3 (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. 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 > 2sigma(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. H-atoms attached to carbon were placed in calculated positions (C—H = 0.95 - 0.99 Å) and included as riding contributions with isotropic displacement parameters 1.2 - 1.5 times those of the attached atoms. Refined as a 2-component inversion twin.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.7819 (3)0.97368 (13)0.19153 (11)0.0424 (4)
O20.7456 (2)1.06296 (11)0.35322 (11)0.0365 (3)
N10.7976 (2)0.54673 (13)0.52816 (12)0.0262 (3)
N20.7894 (2)0.58370 (14)0.63935 (12)0.0283 (3)
N30.7670 (2)0.97218 (13)0.29620 (13)0.0280 (3)
C10.7770 (3)0.70071 (15)0.63659 (14)0.0259 (4)
H10.76900.75000.70230.031*
C20.7771 (2)0.74371 (15)0.52275 (14)0.0215 (3)
C30.7705 (2)0.85588 (15)0.47110 (13)0.0218 (3)
H30.76330.92710.51450.026*
C40.7749 (2)0.85723 (15)0.35380 (14)0.0233 (3)
C50.7852 (3)0.75368 (16)0.28580 (14)0.0273 (4)
H50.78700.76060.20510.033*
C60.7925 (3)0.64353 (17)0.33526 (14)0.0271 (4)
H60.79950.57290.29090.033*
C70.7891 (2)0.63988 (15)0.45514 (14)0.0231 (3)
C80.8223 (3)0.42079 (16)0.50072 (17)0.0309 (4)
H8A0.87750.37920.56800.037*
H8B0.91910.41310.43780.037*
C90.6321 (3)0.3606 (2)0.4662 (2)0.0404 (5)
H9A0.53670.36570.52890.061*
H9B0.65840.27680.44860.061*
H9C0.57770.40020.39870.061*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0605 (10)0.0423 (8)0.0245 (6)−0.0015 (8)0.0002 (7)0.0091 (5)
O20.0481 (8)0.0226 (6)0.0386 (7)0.0004 (6)−0.0015 (7)0.0010 (5)
N10.0279 (7)0.0210 (7)0.0298 (7)0.0007 (6)0.0013 (6)0.0016 (6)
N20.0283 (8)0.0293 (7)0.0274 (7)0.0004 (6)0.0016 (6)0.0026 (6)
N30.0282 (7)0.0276 (8)0.0282 (7)−0.0023 (7)−0.0014 (6)0.0037 (6)
C10.0261 (8)0.0278 (8)0.0238 (8)0.0010 (7)0.0020 (7)0.0002 (6)
C20.0188 (7)0.0218 (8)0.0239 (7)−0.0004 (6)−0.0005 (6)−0.0019 (6)
C30.0206 (7)0.0212 (7)0.0238 (7)−0.0001 (7)−0.0002 (6)−0.0024 (6)
C40.0219 (7)0.0231 (8)0.0249 (7)−0.0004 (7)−0.0004 (6)0.0026 (6)
C50.0291 (9)0.0316 (9)0.0213 (7)−0.0008 (8)−0.0003 (7)−0.0032 (6)
C60.0289 (9)0.0251 (8)0.0274 (8)−0.0003 (8)−0.0002 (6)−0.0066 (7)
C70.0204 (7)0.0214 (8)0.0275 (8)0.0004 (7)0.0005 (6)−0.0011 (6)
C80.0311 (9)0.0189 (9)0.0427 (10)0.0025 (7)0.0049 (7)−0.0002 (7)
C90.0389 (10)0.0277 (10)0.0545 (12)−0.0042 (9)−0.0001 (9)−0.0083 (10)
Geometric parameters (Å, º) top
O1—N31.2322 (19)C3—H30.9500
O2—N31.228 (2)C4—C51.412 (2)
N1—C71.353 (2)C5—C61.367 (3)
N1—N21.370 (2)C5—H50.9500
N1—C81.460 (2)C6—C71.407 (2)
N2—C11.317 (2)C6—H60.9500
N3—C41.458 (2)C8—C91.507 (3)
C1—C21.420 (2)C8—H8A0.9900
C1—H10.9500C8—H8B0.9900
C2—C31.399 (2)C9—H9A0.9800
C2—C71.413 (2)C9—H9B0.9800
C3—C41.377 (2)C9—H9C0.9800
C7—N1—N2111.52 (14)C6—C5—H5119.8
C7—N1—C8127.88 (15)C4—C5—H5119.8
N2—N1—C8120.54 (14)C5—C6—C7116.74 (16)
C1—N2—N1106.35 (14)C5—C6—H6121.6
O2—N3—O1122.76 (15)C7—C6—H6121.6
O2—N3—C4119.14 (14)N1—C7—C6130.88 (17)
O1—N3—C4118.10 (14)N1—C7—C2106.56 (14)
N2—C1—C2111.25 (15)C6—C7—C2122.55 (17)
N2—C1—H1124.4N1—C8—C9113.35 (16)
C2—C1—H1124.4N1—C8—H8A108.9
C3—C2—C7120.14 (14)C9—C8—H8A108.9
C3—C2—C1135.54 (15)N1—C8—H8B108.9
C7—C2—C1104.32 (14)C9—C8—H8B108.9
C4—C3—C2116.25 (15)H8A—C8—H8B107.7
C4—C3—H3121.9C8—C9—H9A109.5
C2—C3—H3121.9C8—C9—H9B109.5
C3—C4—C5123.84 (16)H9A—C9—H9B109.5
C3—C4—N3118.18 (15)C8—C9—H9C109.5
C5—C4—N3117.98 (14)H9A—C9—H9C109.5
C6—C5—C4120.48 (15)H9B—C9—H9C109.5
C7—N1—N2—C1−0.37 (19)N3—C4—C5—C6−179.87 (16)
C8—N1—N2—C1176.88 (17)C4—C5—C6—C70.0 (2)
N1—N2—C1—C2−0.1 (2)N2—N1—C7—C6−179.89 (17)
N2—C1—C2—C3−178.72 (18)C8—N1—C7—C63.1 (3)
N2—C1—C2—C70.54 (19)N2—N1—C7—C20.70 (18)
C7—C2—C3—C40.4 (2)C8—N1—C7—C2−176.29 (17)
C1—C2—C3—C4179.61 (17)C5—C6—C7—N1−178.80 (17)
C2—C3—C4—C50.1 (2)C5—C6—C7—C20.5 (2)
C2—C3—C4—N3179.61 (14)C3—C2—C7—N1178.67 (15)
O2—N3—C4—C3−4.0 (2)C1—C2—C7—N1−0.73 (17)
O1—N3—C4—C3176.12 (16)C3—C2—C7—C6−0.8 (2)
O2—N3—C4—C5175.51 (17)C1—C2—C7—C6179.81 (15)
O1—N3—C4—C5−4.4 (2)C7—N1—C8—C9−81.9 (2)
C3—C4—C5—C6−0.4 (3)N2—N1—C8—C9101.4 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C3—H3···O1i0.952.383.237 (2)150
Symmetry code: (i) −x+3/2, −y+2, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C3—H3···O1i0.952.383.237 (2)150
Symmetry code: (i) −x+3/2, −y+2, z+1/2.

Experimental details

Crystal data
Chemical formulaC9H9N3O2
Mr191.19
Crystal system, space groupOrthorhombic, P212121
Temperature (K)150
a, b, c (Å)6.7563 (1), 11.2307 (2), 11.7323 (3)
V (Å3)890.22 (3)
Z4
Radiation typeCu Kα
µ (mm−1)0.87
Crystal size (mm)0.17 × 0.13 × 0.06
Data collection
DiffractometerBruker D8 VENTURE PHOTON 100 CMOS
Absorption correctionMulti-scan
(SADABS; Bruker, 2016)
Tmin, Tmax0.87, 0.95
No. of measured, independent and
observed [I > 2σ(I)] reflections		6805, 1751, 1689
Rint0.029
(sin θ/λ)max (Å−1)0.618
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.032, 0.083, 1.14
No. of reflections1751
No. of parameters129
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.17, −0.21
Absolute structureRefined as an inversion twin
Absolute structure parameter0.3 (3)

Computer programs: APEX3 (Bruker, 2016), SAINT (Bruker, 2016), SAINT (Bruker, 2016), SHELXT (Sheldrick, 2015a), SHELXL2014 (Sheldrick, 2015b), DIAMOND (Brandenburg & Putz, 2012), SHELXTL (Sheldrick, 2008).

 

Acknowledgements

The support of NSF–MRI Grant No. 1228232 for the purchase of the diffractometer and Tulane University for support of the Tulane Crystallography Laboratory are gratefully acknowledged.

References

First citationBoulhaoua, M., Benchidmi, M., Essassi, E. M., Saadi, M. & El Ammari, L. (2015). Acta Cryst. E71, o780–o781.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationBrandenburg, K. & Putz, H. (2012). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
 First citationBruker (2016). APEX3, SAINT and SADABS. Bruker AXS, Inc., Madison, Wisconsin, USA.  Google Scholar
 First citationEl Brahmi, N., Benchidmi, M., Essassi, E. M., Ladeira, S. & El Ammari, L. (2012). Acta Cryst. E68, o3368.  CSD CrossRef IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2015a). Acta Cryst. A71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2015b). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoIUCrDATA
ISSN: 2414-3146
Volume 1| Part 4| April 2016| x160567
doi:10.1107/S2414314616005678
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