5-Amino-1-(2,6-dichloro-4-nitro­phen­yl)pyrazole-3-carbonitrile

In the title compound, C₁₀H₅Cl₂N₅O₂, the dihedral angle between the pyrazole and benzene ring planes is 80.59 (12)°. The crystal structure is stabilized by N—H...N and N—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.058
• wR factor = 0.144
• Data-to-parameter ratio = 12.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.53
PLAT371_ALERT_2_C Long   C(sp2)-C(sp1) Bond  C7     -   C10    ...       1.45 Ang.
PLAT431_ALERT_2_C Short Inter HL..A Contact  Cl2    ..  O1      ..       3.10 Ang.
PLAT710_ALERT_4_C Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #         37
            N3  -C7  -C10 -N4    171.00  7.00   1.555   1.555   1.555   1.555
PLAT710_ALERT_4_C Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #         38
            C8  -C7  -C10 -N4     -8.00  8.00   1.555   1.555   1.555   1.555

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          3

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The molecular structure of the title compound is similar to 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole, an important starting material for the insecticide fipronil (Clavel et al., 2003; Hatton et al., 1993). The molecule is shown in Fig. 1. It contains two essentially planar rings. The dihedral angle between the pyrazole and benzene ring planes is 80.59 (12)°.

Related literature

For related literature, see: Clavel et al. (2003); Hatton et al. (1993); Hainzl & Casida (1996); Zhong et al. (2005).

S2. Experimental

A suspension of nitrosyl sulfuric acid prepared from sodium nitrite (0.055 mol) and concentrated sulfuric acid (1.5 ml) was diluted with acetic acid (5 ml), cooled to 283 K, and stirred mechanically. To this was added a solution of 2,6-dichloro-4-nitroaniline (0.05 mol) in acetic acid (20 ml) dropwise over 15 minutes at room temperature. This mixture was heated to 335 K for 20 minutes and poured onto a stirred solution of ethyl 2,3-dicyanopropionate (0.05 mol) in acetic acid (10 ml) and water (30 ml) at room temperature. After 15 minutes, water (20 ml) was added, and the oily layer separated. The aqueous solution was then extracted with dichloromethane (30 ml) and the extracts combined with the oil and washed with ammonia solution (to pH=9). The organic phase was then stirred with ammonia (5 ml) for 2 h, and the dichloromethane layer then separated. This was washed with water (30 ml), 1 N hydrochloric acid (30 ml), dried over anhydrous magnesium sulfate, filtered, and evaporated in vacuo to give an oily solid. Crytstallization from ethanol-acetone gave the title compound. Total yield was 81%. Yellow single crystals suitable for X-ray analysis were obtained by slow evaporation of an anhydrous ethanol-acetone (2:1) solution. ¹H NMR (CD₃COCD₃, δ, p.p.m.): 8.51 (s,2H), 6.07 (s,1H), 5.84 (s,2H).; ¹³C NMR (CD₃COCD₃, δ, p.p.m.): 149.2, 148.7, 137.6, 136.2, 131.0, 126.8, 123.7, 113.6, 91.28

S3. Refinement

The two H atoms of the N5 atom were located from difference-density maps and refined with N—H and H···H distances restrained to be 0.85±0.02 Å and 1.45±0.01 Å, respectively, and with U_iso = 1.2U_eq(parent atom). The other H atoms were positioned geometrically and allowed to ride on their parent atoms at distances of Csp²—H = 0.93 Å with U_iso = 1.2U_eq(parent atom).

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2002); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

Fig. 1. The molecular structure showing the atom numbering scheme and displacement ellipsoids at the 50% probability level. Hydrogen atoms are shown as spheres of an arbitrary size.

5-Amino-1-(2,6-dichloro-4-nitrophenyl)pyrazole-3-carbonitrile

Crystal data

C10H5Cl2N5O2	F(000) = 1200
Mr = 298.09	Dx = 1.580 Mg m^−3
Monoclinic, C2/c	Melting point: 473 K
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 13.1756 (13) Å	Cell parameters from 2235 reflections
b = 10.5514 (13) Å	θ = 2.5–24.8°
c = 18.0297 (19) Å	µ = 0.52 mm^−1
β = 91.356 (3)°	T = 298 K
V = 2505.8 (5) Å^3	Block, colorless
Z = 8	0.38 × 0.22 × 0.18 mm

Data collection

Bruker APEX area-detector diffractometer	2211 independent reflections
Radiation source: fine-focus sealed tube	1902 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.026
φ and ω scans	θmax = 25.0°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −15→13
Tmin = 0.826, Tmax = 0.912	k = −12→7
6435 measured reflections	l = −21→20

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.058	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.144	H atoms treated by a mixture of independent and constrained refinement
S = 1.12	w = 1/[σ^2(Fo^2) + (0.0609P)^2 + 3.910P] where P = (Fo^2 + 2Fc^2)/3
2211 reflections	(Δ/σ)max = 0.001
178 parameters	Δρmax = 0.31 e Å^−3
3 restraints	Δρmin = −0.22 e Å^−3

Special details

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.

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

	x	y	z	Uiso*/Ueq
Cl1	−0.08877 (7)	0.03784 (11)	0.32992 (5)	0.0741 (4)
Cl2	0.11826 (9)	0.31258 (15)	0.53159 (6)	0.1012 (5)
O1	−0.3095 (2)	0.0874 (3)	0.5636 (2)	0.0915 (11)
O2	−0.2151 (3)	0.1648 (3)	0.6505 (2)	0.1226 (15)
N1	−0.2305 (3)	0.1292 (3)	0.5878 (2)	0.0732 (10)
N2	0.07792 (16)	0.2094 (2)	0.38293 (12)	0.0389 (6)
N3	0.15519 (17)	0.1271 (2)	0.36863 (13)	0.0409 (6)
N4	0.3713 (2)	0.1004 (3)	0.26417 (18)	0.0640 (8)
N5	0.0188 (2)	0.4179 (3)	0.35515 (18)	0.0650 (9)
H5A	−0.0377 (17)	0.394 (3)	0.3703 (17)	0.055*
H5B	0.021 (2)	0.481 (2)	0.3264 (16)	0.055*
C1	−0.1449 (3)	0.1407 (3)	0.53566 (19)	0.0516 (8)
C2	−0.1559 (2)	0.0850 (3)	0.4670 (2)	0.0521 (8)
H2	−0.2125	0.0359	0.4548	0.063*
C3	−0.0794 (2)	0.1046 (3)	0.41680 (16)	0.0440 (7)
C4	0.0038 (2)	0.1778 (3)	0.43599 (15)	0.0390 (7)
C5	0.0124 (2)	0.2279 (3)	0.50711 (17)	0.0512 (8)
C6	−0.0625 (3)	0.2094 (3)	0.55791 (18)	0.0582 (9)
H6	−0.0570	0.2427	0.6056	0.070*
C7	0.20940 (19)	0.1928 (3)	0.32125 (15)	0.0381 (7)
C8	0.1712 (2)	0.3121 (3)	0.30524 (16)	0.0441 (7)
H8	0.1980	0.3727	0.2738	0.053*
C9	0.0852 (2)	0.3210 (3)	0.34607 (16)	0.0411 (7)
C10	0.3002 (2)	0.1386 (3)	0.29029 (17)	0.0457 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0674 (6)	0.1008 (8)	0.0544 (5)	−0.0178 (5)	0.0048 (4)	−0.0114 (5)
Cl2	0.0827 (8)	0.1520 (13)	0.0691 (7)	−0.0495 (8)	0.0077 (5)	−0.0275 (7)
O1	0.0604 (17)	0.083 (2)	0.133 (3)	0.0106 (16)	0.0556 (18)	0.0401 (19)
O2	0.169 (4)	0.103 (3)	0.101 (3)	−0.035 (2)	0.102 (3)	−0.031 (2)
N1	0.081 (2)	0.0444 (17)	0.097 (3)	0.0071 (17)	0.058 (2)	0.0161 (18)
N2	0.0303 (11)	0.0462 (14)	0.0410 (13)	0.0048 (11)	0.0171 (10)	0.0092 (11)
N3	0.0336 (12)	0.0446 (14)	0.0451 (13)	0.0059 (11)	0.0134 (10)	0.0073 (11)
N4	0.0459 (16)	0.0627 (19)	0.085 (2)	0.0149 (14)	0.0321 (15)	0.0002 (16)
N5	0.0541 (17)	0.0606 (19)	0.082 (2)	0.0221 (15)	0.0395 (16)	0.0264 (16)
C1	0.0544 (19)	0.0429 (17)	0.059 (2)	0.0120 (16)	0.0341 (16)	0.0148 (16)
C2	0.0373 (16)	0.0468 (18)	0.073 (2)	−0.0015 (14)	0.0162 (15)	0.0138 (16)
C3	0.0388 (16)	0.0491 (18)	0.0445 (16)	0.0020 (14)	0.0106 (12)	0.0096 (14)
C4	0.0333 (14)	0.0444 (16)	0.0397 (15)	0.0064 (13)	0.0115 (12)	0.0094 (13)
C5	0.0479 (17)	0.062 (2)	0.0443 (17)	−0.0040 (16)	0.0131 (14)	0.0003 (15)
C6	0.071 (2)	0.061 (2)	0.0433 (18)	0.0038 (19)	0.0199 (16)	0.0036 (16)
C7	0.0305 (14)	0.0446 (16)	0.0395 (15)	0.0035 (12)	0.0109 (11)	−0.0005 (13)
C8	0.0403 (15)	0.0450 (17)	0.0480 (17)	0.0046 (14)	0.0198 (13)	0.0087 (14)
C9	0.0349 (14)	0.0460 (17)	0.0431 (16)	0.0069 (13)	0.0143 (12)	0.0066 (14)
C10	0.0421 (17)	0.0447 (17)	0.0507 (17)	0.0034 (14)	0.0128 (14)	0.0044 (14)

Geometric parameters (Å, º)

Cl1—C3	1.719 (3)	C1—C6	1.358 (5)
Cl2—C5	1.706 (3)	C1—C2	1.374 (5)
O1—N1	1.203 (5)	C2—C3	1.386 (4)
O2—N1	1.204 (5)	C2—H2	0.9300
N1—C1	1.489 (4)	C3—C4	1.378 (4)
N2—C9	1.357 (4)	C4—C5	1.389 (4)
N2—N3	1.367 (3)	C5—C6	1.377 (4)
N2—C4	1.423 (3)	C6—H6	0.9300
N3—C7	1.323 (4)	C7—C8	1.383 (4)
N4—C10	1.133 (4)	C7—C10	1.449 (4)
N5—C9	1.358 (4)	C8—C9	1.369 (4)
N5—H5A	0.837 (16)	C8—H8	0.9300
N5—H5B	0.844 (16)
O1—N1—O2	125.4 (3)	C3—C4—C5	119.5 (3)
O1—N1—C1	117.6 (4)	C3—C4—N2	121.1 (3)
O2—N1—C1	117.0 (4)	C5—C4—N2	119.3 (3)
C9—N2—N3	113.4 (2)	C6—C5—C4	121.0 (3)
C9—N2—C4	126.2 (2)	C6—C5—Cl2	119.8 (3)
N3—N2—C4	120.3 (2)	C4—C5—Cl2	119.1 (2)
C7—N3—N2	101.8 (2)	C1—C6—C5	117.4 (3)
C9—N5—H5A	113 (2)	C1—C6—H6	121.3
C9—N5—H5B	119 (2)	C5—C6—H6	121.3
H5A—N5—H5B	119 (2)	N3—C7—C8	114.4 (2)
C6—C1—C2	124.1 (3)	N3—C7—C10	120.3 (3)
C6—C1—N1	118.0 (3)	C8—C7—C10	125.3 (3)
C2—C1—N1	117.9 (3)	C9—C8—C7	104.6 (3)
C1—C2—C3	117.5 (3)	C9—C8—H8	127.7
C1—C2—H2	121.3	C7—C8—H8	127.7
C3—C2—H2	121.3	N2—C9—N5	122.7 (2)
C4—C3—C2	120.4 (3)	N2—C9—C8	105.8 (2)
C4—C3—Cl1	119.8 (2)	N5—C9—C8	131.3 (3)
C2—C3—Cl1	119.8 (3)	N4—C10—C7	177.2 (3)
C9—N2—N3—C7	−0.4 (3)	N2—C4—C5—C6	173.9 (3)
C4—N2—N3—C7	−176.3 (3)	C3—C4—C5—Cl2	177.2 (2)
O1—N1—C1—C6	167.6 (3)	N2—C4—C5—Cl2	−6.6 (4)
O2—N1—C1—C6	−11.1 (5)	C2—C1—C6—C5	2.6 (5)
O1—N1—C1—C2	−10.1 (5)	N1—C1—C6—C5	−174.9 (3)
O2—N1—C1—C2	171.2 (3)	C4—C5—C6—C1	−0.1 (5)
C6—C1—C2—C3	−2.5 (5)	Cl2—C5—C6—C1	−179.6 (3)
N1—C1—C2—C3	175.0 (3)	N2—N3—C7—C8	0.4 (3)
C1—C2—C3—C4	−0.1 (5)	N2—N3—C7—C10	−179.2 (3)
C1—C2—C3—Cl1	−179.8 (2)	N3—C7—C8—C9	−0.3 (4)
C2—C3—C4—C5	2.5 (5)	C10—C7—C8—C9	179.3 (3)
Cl1—C3—C4—C5	−177.9 (2)	N3—N2—C9—N5	−176.9 (3)
C2—C3—C4—N2	−173.7 (3)	C4—N2—C9—N5	−1.3 (5)
Cl1—C3—C4—N2	6.0 (4)	N3—N2—C9—C8	0.2 (3)
C9—N2—C4—C3	100.3 (4)	C4—N2—C9—C8	175.8 (3)
N3—N2—C4—C3	−84.4 (3)	C7—C8—C9—N2	0.1 (3)
C9—N2—C4—C5	−75.9 (4)	C7—C8—C9—N5	176.8 (3)
N3—N2—C4—C5	99.5 (3)	N3—C7—C10—N4	171 (7)
C3—C4—C5—C6	−2.4 (5)	C8—C7—C10—N4	−8 (8)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N5—H5A···O1^i	0.84 (2)	2.37 (2)	3.154 (4)	156 (3)
N5—H5B···N4^ii	0.84 (2)	2.53 (2)	3.253 (4)	145 (3)
N5—H5B···N4^iii	0.84 (2)	2.58 (3)	3.166 (4)	128 (2)

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