3-tert-Butyl-1-(3-nitro­phen­yl)-1H-pyrazol-5-amine

Simón Hernández-Ortega; Fernando Cuenú-Cabezas; Rodrigo Abonia-González; Armando Cabrera-Ortiz

doi:10.1107/S1600536812042791

. 2012 Oct 20;68(Pt 11):o3171. doi: 10.1107/S1600536812042791

3-tert-Butyl-1-(3-nitrophenyl)-1H-pyrazol-5-amine

Simón Hernández-Ortega ^a,^*, Fernando Cuenú-Cabezas ^b, Rodrigo Abonia-González ^c, Armando Cabrera-Ortiz ^a

PMCID: PMC3515264 PMID: 23284484

Abstract

In the title compound, C₁₃H₁₆N₄O₂, the pyrazole ring forms a dihedral angle of 50.61 (6)° with the 3-nitro-phenyl ring. The plane of the nitro group is twisted by 6.8 (7)° out of the plane of the phenyl ring. In the crystal, the molecules are linked by N—H⋯N and N—H⋯O hydrogen bonds, forming sheets in the bc plane. In addition, a weak C—H⋯N interaction is observed.

Related literature

For background to pyrazole-based ligands, see; Ahmed et al. (2005 ▶); Abonia et al. (2002 ▶, 2004 ▶, 2010 ▶); Guerrero et al. (2009 ▶); Quiroga et al. (2008 ▶); Schutznerová, et al. (2012 ▶). For structure of an isomer of the title compound, see: Low et al. (2004 ▶).

Experimental

Crystal data

C₁₃H₁₆N₄O₂
M _r = 260.30
Monoclinic,
a = 11.9421 (14) Å
b = 9.6419 (11) Å
c = 11.7694 (13) Å
β = 93.504 (2)°
V = 1352.6 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 298 K
0.46 × 0.36 × 0.32 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer
14529 measured reflections
2486 independent reflections
2036 reflections with I > 2σ(I)
R _int = 0.044

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.115
S = 1.05
2486 reflections
181 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Data collection: SMART (Bruker, 1999 ▶); cell refinement: SAINT (Bruker, 1999 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Click here for additional data file.^{(20.5KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812042791/bt6847sup1.cif

e-68-o3171-sup1.cif^{(20.5KB, cif)}

Click here for additional data file.^{(122.1KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812042791/bt6847Isup2.hkl

e-68-o3171-Isup2.hkl^{(122.1KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N4—H4A⋯N2ⁱ	0.90 (1)	2.23 (1)	3.1195 (17)	172 (2)
N4—H4B⋯O1ⁱⁱ	0.90 (1)	2.39 (1)	3.241 (2)	160 (2)
C14—H14⋯N4ⁱⁱⁱ	0.93	2.54	3.403 (2)	155

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

FCC and RAG thanks the Universidad del Valle and the Universidad del Quindío for financial support to project 542. ACO thanks the DGAPA–UNAM for financial support (PAPIIT IN203209). SHO thanks the Consejo Superior de Investigaciones Científicas (CSIC) of Spain for the award of a licence for the use of the Cambridge Structural Database.

supplementary crystallographic information

Comment

The recent past has evidenced an ever-increasing interest in pyrazole based ligands. The interest in such compounds is due, first of all, to their variety of coordination complexes with a great number of metal ions and, second, to their ability to provide an extensive variety of coordination geometries and significant structural nuclearity when introducing different kinds of heteroatoms (Ahmed et al. 2005; Schutznerová et al. 2012). The past few years have seen considerable rise in interest in the design of various pyrazole-based ligands for particular metal binding site (Guerrero et al. 2009).

As a part of our current research work focused on the development of new bioactive heterocyclic compounds and continuing with the use of pyrazolic Schiff bases (Quiroga et al., 2008; Abonia et al. 2002, 2004, 2010), in the synthesis of pyrazolopyrimidines, we want to describe the compound 5-amino-3-tert-butyl-1-(3-nitro-phenyl)-1H-pyrazole (I), which is a structural isomer of a related compound previously reported by Low (Low et al., 2004).

The structure of the title compound is shown in Figure 1. The compound consists of a ring pyrazole substituted by 3-nitro-phenyl ring bonded to N1, amino group in C5 and tertbutyl group in C3. The pyrazole and phenyl rings are not coplanar, they are forming a dihedral angle of 50.61 (6)°. The nitro group is rotated around C14—N3 bond by 6.8 (3)°. These angle values are larger than those described for the isomeric compound 5-amino-3-tertbutyl-1-(4-nitro-phenyl)-1H-pyrazole (Low et al., 2004). In the crystal, the molecules are linked by N—H–N and N—H–O intermolecular hydrogen bonds forming sheets in the bc plane. In additon, a weak intermolecular C-H···N interaction is observed (Figure 2, Table 1).

Experimental

To a solution of conc hydrochloric acid (3.8 ml) in water (33 ml), 3-nitrophenylhydrazine (1.5001 g, 9.87 mmol) and 4,4-dimethyl-3-oxopentanenitrile (1.8502 g, 14.80 mmol) were added. The mixture was heated at 70 °C for 1 h. Then, conc hydrochloric acid (3.8 ml) was added and the mixture was heated for 1 h more. After cooling, crushed ice was added and neutralized with conc ammonium hydroxide. The resulting solid was filtered under reduced pressure, washed with cold water (3 X 5 ml) and dried at ambient temperature affording the title compound (I) as a yellow solid [yield 1.744 g, 68%, m.p. 375 K]. MS (70 eV) m/z (%): 260 (55), 245 (100), 218 (88), 190 (73). Anal. Calc. for C₁₃H₁₆N₄O₂; C 59.99; H 6.20; N 21.52%, found C 60.36; H 6.42; N 21.88%. Crystals of the title compound suitable for single-crystal X-ray diffraction were grown by slow diffusion of pentane into a CH₂Cl₂ solution of the title compound.