5-Amino-1-(2-chloro­phen­yl)-1H-pyrazole-4-carbonitrile

In the title compound, C₁₀H₇ClN₄, the dihedral angle between the pyrazole and benzene ring planes is 69.48 (7)°. The crystal structure is stabilized by two N—H...N hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.047
• wR factor = 0.125
• Data-to-parameter ratio = 13.1

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT411_ALERT_2_B Short Inter H...H Contact  H3     ..  H3      ..       2.08 Ang.

Alert level C
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.03
PLAT371_ALERT_2_C Long   C(sp2)-C(sp1) Bond  C8     -   C10    ...       1.42 Ang.
PLAT710_ALERT_4_C Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #         29
            C7  -C8  -C10 -N4    145.00 16.00   1.555   1.555   1.555   1.555
PLAT710_ALERT_4_C Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #         30
            C9  -C8  -C10 -N4    -36.00 16.00   1.555   1.555   1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.85(2), Rep    0.850(9) ......       2.22 su-Ra
              N3   -H3A     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.85(2), Rep    0.850(9) ......       2.22 su-Ra
              N3   -H3B     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.85(2), Rep    0.850(9) ......       2.22 su-Ra
              N3   -H3A     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.85(2), Rep    0.850(9) ......       2.22 su-Ra
              N3   -H3B     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
   1 ALERT level B = Potentially serious problem
   8 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   4 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

---

S1. Comment

The title compound, (Fig 1), is an important starting material for the synthesis of 1-(2-chlorophenyl)-4-substituted pyrazolo[3,4-d]pyrimidine, which is a potential purine antagonist (Cheng & Robins, 1956). The dihedral angle between the planar pyrazole and benzene ring is 69.48 (7)°. In the crystal packing, Fig. 2, there are two kinds of N—H—N hydrogen bonds; one to the cyano nitrogen and a second to one of the pyrazol ring N atoms.

Related literature

For related literature, see: Campbell & James (1986); Cheng & Robins (1965); Holla et al. (2006).

S2. Experimental

o-Chloroaniline (5 mmol) was dissolved in concentrated hydrochloric acid (2.5 ml), then the system was cooled with an ice bath, and kept at a temperature between 273k-278k. Sodium nitrate (5.12 mmol) was then slowly added in a dropwise fashion and the mixture was stirred for 30 min. The resulting diazonium salt was added dropwise into a solution of hydrochloric acid and stannous chloride (10 mmol). After stirring for 1 h stirring, sodium hydroxide was used to neutralize the solution to a PH = 7–8. Following the methods of Holla et al.(2006) and Campbell (1986), ethoxymethylenemalononitrile (5 mmol) was then added, appended ethanol as solvent, and refluxed for 1 h followed by filtration and washing several times with acetone, The organic solvent was distilled off, then the solution was filtered again to get the title compound (I) as a solid product (total yield of 81%). Colourless single crystals suitable for X-ray analysis were obtained by slow evaporation of an anhydrous ethanol-acetone (2:1) solution of (I)(m.p. 397 K). ¹H NMR (C_DCl₃, δ, p.p.m.): 4.57(s, 2H), 7.45(m, 3H), 7.57(d, 1H), 7.65(s, 1H).; ¹³C NMR (C_DCl₃, δ, p.p.m.): 127.6 (1 C), 130.4 (1 C), 133.4 (1 C), 119.1 (1 C), 112.8 (1 C), 143.6 (1 C), 151.9 (1 C), 72.3 (1 C), 115.4 (1 C), 152.0 (1 C).

S3. Refinement

All H atoms were initially located in a difference Fourier map but were eventually placed in their geometrically idealized positions and constrained to ride on their parent atoms, with N—H = 0.85 (2) Å and C—H = 0.93 Å, and with U_iso(H) = 1.2_eq(C,N).

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; 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.

Figures

Fig. 1. The molecular structure of (I) showing the atom numbering scheme and displacement ellipsoids at 50% probability level.

5-Amino-1-(2-chlorophenyl)-1H-pyrazole-4-carbonitrile

Crystal data

C10H7ClN4	F(000) = 448
Mr = 218.65	Dx = 1.379 Mg m^−3
Monoclinic, P21/n	Melting point: 397 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 11.2005 (10) Å	Cell parameters from 2518 reflections
b = 8.8432 (8) Å	θ = 3.0–24.9°
c = 11.6970 (11) Å	µ = 0.33 mm^−1
β = 114.666 (1)°	T = 298 K
V = 1052.85 (17) Å^3	Block, colorless
Z = 4	0.42 × 0.31 × 0.23 mm

Data collection

Bruker APEX area-detector diffractometer	1855 independent reflections
Radiation source: fine-focus sealed tube	1625 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.016
φ and ω scans	θmax = 25.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −13→8
Tmin = 0.873, Tmax = 0.927	k = −10→9
5334 measured reflections	l = −13→13

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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.125	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0645P)^2 + 0.3491P] where P = (Fo^2 + 2Fc^2)/3
1855 reflections	(Δ/σ)max = 0.002
142 parameters	Δρmax = 0.17 e Å^−3
3 restraints	Δρmin = −0.25 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	0.67558 (6)	0.49111 (8)	0.01439 (6)	0.0744 (3)
N1	0.69800 (15)	0.6722 (2)	0.23917 (15)	0.0495 (4)
N2	0.60604 (16)	0.7705 (2)	0.15579 (16)	0.0574 (5)
N3	0.73237 (18)	0.5163 (2)	0.41531 (18)	0.0559 (5)
N4	0.3825 (2)	0.6163 (3)	0.4018 (2)	0.0893 (8)
C1	0.81807 (18)	0.6483 (2)	0.22720 (18)	0.0478 (5)
C2	0.8178 (2)	0.5725 (3)	0.12405 (18)	0.0542 (5)
C3	0.9322 (2)	0.5576 (4)	0.1087 (2)	0.0784 (8)
H3	0.9316	0.5078	0.0384	0.094*
C4	1.0475 (2)	0.6159 (4)	0.1966 (3)	0.0829 (8)
H4	1.1246	0.6064	0.1855	0.099*
C5	1.0490 (2)	0.6879 (3)	0.3005 (2)	0.0703 (7)
H5	1.1276	0.7256	0.3608	0.084*
C6	0.9347 (2)	0.7047 (3)	0.3161 (2)	0.0596 (6)
H6	0.9360	0.7542	0.3868	0.072*
C7	0.65749 (18)	0.6105 (2)	0.32239 (17)	0.0453 (5)
C8	0.53318 (19)	0.6713 (2)	0.29280 (19)	0.0496 (5)
C9	0.50854 (19)	0.7673 (3)	0.1899 (2)	0.0562 (6)
H9	0.4315	0.8225	0.1503	0.067*
C10	0.4498 (2)	0.6396 (3)	0.3535 (2)	0.0602 (6)
H3A	0.7891 (19)	0.463 (2)	0.403 (2)	0.072*
H3B	0.694 (2)	0.475 (2)	0.456 (2)	0.072*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0615 (4)	0.0945 (5)	0.0607 (4)	−0.0166 (3)	0.0190 (3)	−0.0154 (3)
N1	0.0382 (8)	0.0673 (11)	0.0470 (9)	0.0038 (8)	0.0216 (7)	0.0056 (8)
N2	0.0451 (9)	0.0717 (12)	0.0545 (10)	0.0064 (9)	0.0198 (8)	0.0118 (9)
N3	0.0499 (10)	0.0729 (12)	0.0563 (11)	0.0114 (9)	0.0332 (9)	0.0117 (9)
N4	0.0585 (12)	0.133 (2)	0.0959 (16)	0.0179 (13)	0.0512 (12)	0.0255 (15)
C1	0.0394 (10)	0.0623 (12)	0.0467 (10)	0.0009 (9)	0.0229 (8)	0.0049 (9)
C2	0.0479 (12)	0.0732 (14)	0.0453 (11)	−0.0076 (10)	0.0232 (9)	−0.0019 (10)
C3	0.0616 (15)	0.124 (2)	0.0647 (15)	−0.0091 (15)	0.0414 (13)	−0.0199 (15)
C4	0.0511 (14)	0.129 (2)	0.0846 (18)	−0.0084 (14)	0.0439 (13)	−0.0108 (17)
C5	0.0413 (12)	0.0935 (18)	0.0734 (15)	−0.0097 (12)	0.0211 (11)	−0.0098 (13)
C6	0.0472 (12)	0.0777 (15)	0.0544 (12)	−0.0019 (11)	0.0216 (10)	−0.0099 (11)
C7	0.0386 (10)	0.0564 (11)	0.0441 (10)	−0.0018 (9)	0.0205 (8)	−0.0052 (9)
C8	0.0384 (10)	0.0610 (12)	0.0531 (11)	−0.0020 (9)	0.0228 (8)	−0.0036 (9)
C9	0.0386 (11)	0.0692 (14)	0.0595 (12)	0.0048 (10)	0.0191 (9)	0.0030 (10)
C10	0.0415 (11)	0.0777 (15)	0.0655 (13)	0.0058 (10)	0.0264 (10)	0.0040 (11)

Geometric parameters (Å, º)

Cl1—C2	1.731 (2)	C3—C4	1.372 (4)
N1—C7	1.349 (2)	C3—H3	0.9300
N1—N2	1.389 (2)	C4—C5	1.365 (4)
N1—C1	1.425 (2)	C4—H4	0.9300
N2—C9	1.310 (3)	C5—C6	1.376 (3)
N3—C7	1.348 (3)	C5—H5	0.9300
N3—H3A	0.850 (9)	C6—H6	0.9300
N3—H3B	0.850 (9)	C7—C8	1.395 (3)
N4—C10	1.134 (3)	C8—C9	1.403 (3)
C1—C2	1.379 (3)	C8—C10	1.416 (3)
C1—C6	1.379 (3)	C9—H9	0.9300
C2—C3	1.372 (3)
C7—N1—N2	112.69 (15)	C3—C4—H4	120.0
C7—N1—C1	128.77 (16)	C4—C5—C6	120.1 (2)
N2—N1—C1	118.54 (15)	C4—C5—H5	119.9
C9—N2—N1	103.91 (16)	C6—C5—H5	119.9
C7—N3—H3A	117.9 (16)	C5—C6—C1	120.1 (2)
C7—N3—H3B	115.3 (16)	C5—C6—H6	119.9
H3A—N3—H3B	116.5 (16)	C1—C6—H6	119.9
C2—C1—C6	119.41 (18)	N3—C7—N1	123.25 (17)
C2—C1—N1	120.06 (17)	N3—C7—C8	131.22 (18)
C6—C1—N1	120.50 (18)	N1—C7—C8	105.46 (17)
C3—C2—C1	120.0 (2)	C7—C8—C9	105.35 (17)
C3—C2—Cl1	118.93 (18)	C7—C8—C10	126.7 (2)
C1—C2—Cl1	121.02 (15)	C9—C8—C10	127.92 (19)
C2—C3—C4	120.2 (2)	N2—C9—C8	112.58 (18)
C2—C3—H3	119.9	N2—C9—H9	123.7
C4—C3—H3	119.9	C8—C9—H9	123.7
C5—C4—C3	120.1 (2)	N4—C10—C8	179.0 (3)
C5—C4—H4	120.0
C7—N1—N2—C9	−0.1 (2)	C2—C1—C6—C5	1.3 (3)
C1—N1—N2—C9	179.50 (18)	N1—C1—C6—C5	−176.6 (2)
C7—N1—C1—C2	111.1 (2)	N2—N1—C7—N3	−177.35 (19)
N2—N1—C1—C2	−68.4 (3)	C1—N1—C7—N3	3.1 (3)
C7—N1—C1—C6	−71.1 (3)	N2—N1—C7—C8	−0.2 (2)
N2—N1—C1—C6	109.5 (2)	C1—N1—C7—C8	−179.70 (19)
C6—C1—C2—C3	−1.9 (4)	N3—C7—C8—C9	177.2 (2)
N1—C1—C2—C3	176.0 (2)	N1—C7—C8—C9	0.4 (2)
C6—C1—C2—Cl1	176.53 (18)	N3—C7—C8—C10	−3.7 (4)
N1—C1—C2—Cl1	−5.6 (3)	N1—C7—C8—C10	179.4 (2)
C1—C2—C3—C4	1.0 (4)	N1—N2—C9—C8	0.3 (2)
Cl1—C2—C3—C4	−177.5 (2)	C7—C8—C9—N2	−0.4 (3)
C2—C3—C4—C5	0.6 (5)	C10—C8—C9—N2	−179.5 (2)
C3—C4—C5—C6	−1.2 (5)	C7—C8—C10—N4	145 (16)
C4—C5—C6—C1	0.3 (4)	C9—C8—C10—N4	−36 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3A···N2^i	0.85 (1)	2.33 (1)	3.154 (3)	164 (2)
N3—H3B···N4^ii	0.85 (1)	2.31 (1)	3.147 (3)	170 (2)

Symmetry codes: (i) −x+3/2, y−1/2, −z+1/2; (ii) −x+1, −y+1, −z+1.