5-Nitro-1-(prop-2-yn-1-yl)-1H-indazole

The packing of the title mol­ecule, C₁₀H₇N₃O₂, features the formation of weak dimers via pairwise C—H⋯O inter­actions across centers of symmetry. The prop-2-yn-1-yl moiety is twisted out of the plane of the indazole unit by 78.53 (17)°.

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Chemical scheme

Structure description

Recently there has been considerable inter­est in the chemistry of indazoles. This is undoubtedly due to a broad variety of biological functions of indazole derivatives such as anti-inflammatory (Schmidt et al., 2008), anti­bacterial (Shafakat Ali et al., 2012) and anti­tumor activities (Abbassi et al., 2014). The present work is a continuation of our work on indazole derivatives (El Brahmi et al., 2011). In contrast to 1-(5-nitro-1H-indazol-1-yl)ethanone, the nitro group here is within a degree of planarity with the indazole moiety (Fig. 1). However, the prop-2-yn-1-yl moiety is twisted out of the plane of the indazole unit by 78.53 (17)°. In the crystal, mol­ecules are linked by pairs of C3—H3⋯O2 inter­actions, forming inversion dimers (Fig. 2 and Table 1).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O2^i	0.95	2.47	3.298 (2)	146
Symmetry code: (i) -x+2, -y+1, -z+1.

Figure 1 The title mol­ecule with the atom-labeling scheme and 50% probability ellipsoids.

Figure 2 Packing viewed down the a axis with C—H⋯O inter­actions shown as dotted lines.

Synthesis and crystallization

To a solution of 5-nitro-1H-indazole (1 g, 6.13 mmol) in acetone (30 ml) was added potassium hydroxide (0.38 g, 6.8 mmol). After 15 min of stirring at room temperature, propargyl bromide (1.09 ml, 12.26 mmol) was added dropwise. Upon disappearance of the starting material as indicated by TLC, the resulting mixture was evaporated. The crude material was dissolved with EtOAc (50 ml), washed with water and brine, dried over MgSO4 and the solvent was evaporated in vacuo. The resulting residue was purified by column chromatography (EtOAc/hexane 1/9). The title compound was recrystallized from ethanol at room temperature giving colorless crystals (yield: 57%; m.p. 355–357 K).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. Trial refinements with both the single component reflection file extracted from the full data set by TWINABS and with the full twinned data set indicated that the former refinement gave better results, as judged by lower values for R₁, wR₂, su's and residual features in the final difference map.

Table 2
Experimental details

Crystal data
Chemical formula	C10H7N3O2
Mr	201.19
Crystal system, space group	Monoclinic, P21/n
Temperature (K)	150
a, b, c (Å)	4.0105 (1), 21.0705 (7), 10.7451 (4)
β (°)	96.323 (2)
V (Å^3)	902.47 (5)
Z	4
Radiation type	Cu Kα
μ (mm^−1)	0.90
Crystal size (mm)	0.22 × 0.17 × 0.14
Data collection
Diffractometer	Bruker D8 VENTURE PHOTON 100 CMOS
Absorption correction	Multi-scan (TWINABS; Sheldrick, 2009)
Tmin, Tmax	0.58, 0.88
No. of measured, independent and observed [I > 2σ(I)] reflections	11748, 1747, 1561
Rint	0.045
(sin θ/λ)max (Å^−1)	0.618
Refinement
R[F^2 > 2σ(F^2)], wR(F^2), S	0.044, 0.124, 1.04
No. of reflections	1747
No. of parameters	141
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å^−3)	0.22, −0.21
Computer programs: APEX3 and SAINT (Bruker, 2016), CELL_NOW (Sheldrick, 2008a), SHELXT (Sheldrick, 2015a), SHELXL2014 (Sheldrick, 2015b), DIAMOND (Brandenburg & Putz, 2012) and SHELXTL (Sheldrick, 2008b).

Structural data

S1. Experimental

To a solution of 5-nitro-1H-indazole (1 g, 6.13 mmol) in acetone (30 ml) was added potassium hydroxide (0.38 g, 6.8 mmol). After 15 min of stirring at room temperature, propargyl bromide (1.09 ml, 12.26 mmol) was added dropwise. Upon disappearance of the starting material as indicated by TLC, the resulting mixture was evaporated. The crude material was dissolved with EtOAc (50 ml), washed with water and brine, dried over MgSO4 and the solvent was evaporated in vacuo. The resulting residue was purified by column chromatography (EtOAc/hexane 1/9). The title compound was recrystallized from ethanol at room temperature giving colorless crystals (yield: 57%; m.p. 355–357 K).

S2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. Trial refinements with both the single component reflection file extracted from the full data set by TWINABS and with the full twinned data set indicated that the former refinement gave better results, as judged by lower values for R₁, wR₂, su's and residual features in the final difference map.

Structure description

Recently there has been considerable interest in the chemistry of indazoles. This is undoubtedly due to a broad variety of biological functions of indazole derivatives such as anti-inflammatory (Schmidt et al., 2008), antibacterial (Shafakat Ali et al., 2012) and antitumor activities (Abbassi et al., 2014). The present work is a continuation of our work on indazole derivatives (El Brahmi et al., 2011). In contrast to 1-(5-nitro-1H-indazol-1-yl)ethanone, the nitro group here is within a degree of planarity with the indazole moiety (Fig. 1). However, the prop-2-yn-1-yl moiety is twisted out of the plane of the indazole unit by 78.53 (17)°. In the crystal, the molecules form weak dimers via pairwise C3—H3···O2 interactions across centers of symmetry (Fig. 2 and Table 1).

Computing details

Data collection: APEX3 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016) and CELL_NOW (Sheldrick, 2008a); 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, 2008b).

Figures

	Fig. 1. The title molecule with the atom-labeling scheme and 50% probability ellipsoids.
	Fig. 2. Packing viewed down the a axis with C—H···O interactions shown as dotted lines.

5-Nitro-1-(prop-2-yn-1-yl)-1H-indazole

Crystal data

C10H7N3O2	F(000) = 416
Mr = 201.19	Dx = 1.481 Mg m^−3
Monoclinic, P21/n	Cu Kα radiation, λ = 1.54178 Å
a = 4.0105 (1) Å	Cell parameters from 6907 reflections
b = 21.0705 (7) Å	θ = 4.2–72.4°
c = 10.7451 (4) Å	µ = 0.90 mm^−1
β = 96.323 (2)°	T = 150 K
V = 902.47 (5) Å^3	Block, colourless
Z = 4	0.22 × 0.17 × 0.14 mm

Data collection

Bruker D8 VENTURE PHOTON 100 CMOS diffractometer	1747 independent reflections
Radiation source: INCOATEC IµS micro–focus source	1561 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.045
Detector resolution: 10.4167 pixels mm^-1	θmax = 72.4°, θmin = 4.2°
ω scans	h = −4→4
Absorption correction: multi-scan (TWINABS; Sheldrick, 2009)	k = −26→26
Tmin = 0.58, Tmax = 0.88	l = −12→−2
11748 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.044	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.124	w = 1/[σ^2(Fo^2) + (0.0769P)^2 + 0.2542P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max < 0.001
1747 reflections	Δρmax = 0.22 e Å^−3
141 parameters	Δρmin = −0.20 e Å^−3
0 restraints	Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0086 (15)

Special details

Experimental. Analysis of 644 reflections having I/σ(I) > 12 and chosen from the full data set with CELL_NOW (Sheldrick, 2008) showed the crystal to belong to the monoclinic system and to be twinned by a 180° rotation about the a axis. The raw data were processed using the multi-component version of SAINT under control of the two-component orientation file generated by CELL_NOW.

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. H-atoms attached to aromatic and carbon atoms were placed in calculated positions (C—H = 0.95 − 0.99 Å) and included as riding contributions with isotropic displacement parameters 1.2 times those of the attached atoms. Trial refinements with both the single component reflection file extracted from the full data set by TWINABS and with the full twinned data set indicated that the former refinement gave better results as judged by lower values for R1, wR2, su's and residual features in the final difference map.

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

	x	y	z	Uiso*/Ueq
O1	0.6905 (4)	0.49477 (6)	0.13174 (12)	0.0456 (4)
O2	0.9003 (3)	0.52591 (5)	0.31507 (11)	0.0416 (4)
N1	0.2066 (3)	0.28236 (6)	0.47196 (12)	0.0268 (3)
N2	0.3207 (4)	0.29212 (6)	0.59556 (12)	0.0315 (3)
N3	0.7330 (3)	0.48851 (6)	0.24594 (13)	0.0299 (3)
C1	0.4940 (4)	0.34546 (7)	0.59953 (15)	0.0318 (4)
H1	0.6022	0.3638	0.6740	0.038*
C2	0.4980 (4)	0.37187 (7)	0.47786 (14)	0.0255 (3)
C3	0.6386 (4)	0.42590 (7)	0.42929 (14)	0.0261 (4)
H3	0.7658	0.4556	0.4815	0.031*
C4	0.5824 (4)	0.43369 (6)	0.30145 (14)	0.0251 (4)
C5	0.3948 (4)	0.39102 (7)	0.22039 (14)	0.0272 (4)
H5	0.3651	0.3990	0.1329	0.033*
C6	0.2552 (4)	0.33801 (7)	0.26761 (14)	0.0262 (4)
H6	0.1280	0.3087	0.2146	0.031*
C7	0.3087 (4)	0.32901 (6)	0.39784 (15)	0.0241 (3)
C8	−0.0010 (4)	0.22729 (7)	0.43653 (16)	0.0305 (4)
H8A	−0.1252	0.2349	0.3530	0.037*
H8B	−0.1677	0.2221	0.4972	0.037*
C9	0.1934 (4)	0.16838 (7)	0.43243 (14)	0.0276 (4)
C10	0.3423 (4)	0.12015 (7)	0.42753 (16)	0.0327 (4)
H10	0.462 (5)	0.0839 (10)	0.4232 (18)	0.043 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0688 (10)	0.0379 (7)	0.0298 (6)	−0.0131 (6)	0.0035 (6)	0.0046 (5)
O2	0.0524 (8)	0.0313 (6)	0.0400 (7)	−0.0131 (5)	0.0002 (6)	−0.0025 (5)
N1	0.0272 (7)	0.0240 (6)	0.0296 (7)	0.0018 (5)	0.0058 (5)	−0.0004 (5)
N2	0.0380 (8)	0.0301 (7)	0.0269 (7)	0.0044 (5)	0.0055 (6)	0.0007 (5)
N3	0.0340 (7)	0.0247 (7)	0.0312 (7)	0.0007 (5)	0.0046 (5)	−0.0007 (5)
C1	0.0400 (9)	0.0278 (8)	0.0276 (8)	0.0028 (6)	0.0039 (7)	−0.0011 (6)
C2	0.0273 (7)	0.0225 (7)	0.0268 (8)	0.0043 (5)	0.0040 (6)	−0.0036 (6)
C3	0.0284 (8)	0.0221 (7)	0.0274 (8)	0.0030 (5)	0.0017 (6)	−0.0048 (6)
C4	0.0252 (8)	0.0209 (7)	0.0296 (8)	0.0029 (5)	0.0052 (6)	−0.0011 (6)
C5	0.0287 (8)	0.0282 (8)	0.0251 (7)	0.0028 (5)	0.0042 (6)	−0.0026 (6)
C6	0.0246 (8)	0.0267 (7)	0.0274 (8)	0.0007 (5)	0.0033 (6)	−0.0055 (6)
C7	0.0233 (7)	0.0208 (7)	0.0291 (8)	0.0043 (5)	0.0066 (6)	−0.0018 (5)
C8	0.0258 (8)	0.0265 (7)	0.0402 (9)	−0.0016 (6)	0.0082 (6)	−0.0001 (6)
C9	0.0299 (8)	0.0266 (8)	0.0268 (8)	−0.0042 (6)	0.0058 (6)	0.0014 (6)
C10	0.0374 (9)	0.0265 (8)	0.0342 (9)	0.0022 (6)	0.0031 (7)	−0.0020 (6)

Geometric parameters (Å, º)

O1—N3	1.2272 (18)	C3—H3	0.9500
O2—N3	1.2302 (18)	C4—C5	1.410 (2)
N1—C7	1.3564 (19)	C5—C6	1.372 (2)
N1—N2	1.3718 (18)	C5—H5	0.9500
N1—C8	1.4542 (19)	C6—C7	1.405 (2)
N2—C1	1.320 (2)	C6—H6	0.9500
N3—C4	1.4608 (19)	C8—C9	1.469 (2)
C1—C2	1.423 (2)	C8—H8A	0.9900
C1—H1	0.9500	C8—H8B	0.9900
C2—C3	1.397 (2)	C9—C10	1.183 (2)
C2—C7	1.410 (2)	C10—H10	0.91 (2)
C3—C4	1.377 (2)
C7—N1—N2	111.70 (12)	C5—C4—N3	117.93 (13)
C7—N1—C8	128.73 (14)	C6—C5—C4	120.17 (14)
N2—N1—C8	119.56 (13)	C6—C5—H5	119.9
C1—N2—N1	106.10 (13)	C4—C5—H5	119.9
O1—N3—O2	122.77 (13)	C5—C6—C7	117.03 (14)
O1—N3—C4	118.37 (13)	C5—C6—H6	121.5
O2—N3—C4	118.85 (13)	C7—C6—H6	121.5
N2—C1—C2	111.26 (14)	N1—C7—C6	131.27 (14)
N2—C1—H1	124.4	N1—C7—C2	106.46 (14)
C2—C1—H1	124.4	C6—C7—C2	122.28 (14)
C3—C2—C7	120.44 (14)	N1—C8—C9	113.07 (13)
C3—C2—C1	135.07 (14)	N1—C8—H8A	109.0
C7—C2—C1	104.48 (14)	C9—C8—H8A	109.0
C4—C3—C2	116.19 (14)	N1—C8—H8B	109.0
C4—C3—H3	121.9	C9—C8—H8B	109.0
C2—C3—H3	121.9	H8A—C8—H8B	107.8
C3—C4—C5	123.89 (14)	C10—C9—C8	178.21 (17)
C3—C4—N3	118.16 (13)	C9—C10—H10	178.1 (14)
C7—N1—N2—C1	0.38 (17)	N3—C4—C5—C6	178.43 (13)
C8—N1—N2—C1	−178.83 (13)	C4—C5—C6—C7	0.0 (2)
N1—N2—C1—C2	−0.14 (18)	N2—N1—C7—C6	179.25 (14)
N2—C1—C2—C3	179.98 (16)	C8—N1—C7—C6	−1.6 (3)
N2—C1—C2—C7	−0.13 (18)	N2—N1—C7—C2	−0.47 (16)
C7—C2—C3—C4	−0.4 (2)	C8—N1—C7—C2	178.66 (13)
C1—C2—C3—C4	179.45 (16)	C5—C6—C7—N1	−179.96 (14)
C2—C3—C4—C5	0.2 (2)	C5—C6—C7—C2	−0.3 (2)
C2—C3—C4—N3	−178.21 (12)	C3—C2—C7—N1	−179.74 (13)
O1—N3—C4—C3	178.20 (14)	C1—C2—C7—N1	0.35 (16)
O2—N3—C4—C3	−0.8 (2)	C3—C2—C7—C6	0.5 (2)
O1—N3—C4—C5	−0.3 (2)	C1—C2—C7—C6	−179.39 (14)
O2—N3—C4—C5	−179.27 (14)	C7—N1—C8—C9	102.40 (18)
C3—C4—C5—C6	0.1 (2)	N2—N1—C8—C9	−78.53 (17)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O2^i	0.95	2.47	3.298 (2)	146

Symmetry code: (i) −x+2, −y+1, −z+1.