(E)-N′-Hy­droxy-1,3-diphenyl-4,5-di­hydro-1H-pyrazole-5-carboximidamide

Chandra; N Srikantamurthy; K B Umesha; S Jeyaseelan; M Mahendra

doi:10.1107/S1600536812019630

. 2012 May 5;68(Pt 6):o1661–o1662. doi: 10.1107/S1600536812019630

(E)-N′-Hydroxy-1,3-diphenyl-4,5-dihydro-1H-pyrazole-5-carboximidamide

Chandra ^a, N Srikantamurthy ^b, K B Umesha ^b, S Jeyaseelan ^c, M Mahendra ^a,^*

PMCID: PMC3379259 PMID: 22719457

Abstract

In the molecule of the title compound, C₁₆H₁₆N₄O, the pyrazole ring makes dihedral angles of 8.52 (13) and 9.26 (12)° with the phenyl rings. The dihedral angle between the benzene rings is 1.86 (13)°. In the crystal, molecules are linked into centrosymmetric dimers via pairs of O—H⋯N hydrogen bonds. Weak N—H⋯N interactions connect the dimers into a chain along the [100] direction. The pyrazole ring adopts a highly flattened envelope conformation.

Related literature

For the biological activity of pyrazoles, see: Da Sliva et al. (2010 ▶); Farag et al. (2010 ▶); Khode et al. (2009 ▶); Boschi et al. (2011 ▶); Ghorab et al. (2010 ▶); Husain et al. (2008 ▶); Taj et al. (2011 ▶); Mikhaylichenko et al. (2009 ▶). For bond-length data, see: Allen et al. (1987 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶). For a related structure, see: Fun et al. (2011 ▶). graphic file with name e-68-o1661-scheme1.jpg

Experimental

Crystal data

C₁₆H₁₆N₄O
M _r = 280.33
Triclinic,
a = 7.845 (11) Å
b = 8.940 (12) Å
c = 11.116 (15) Å
α = 99.50 (2)°
β = 99.76 (2)°
γ = 106.70 (2)°
V = 716.8 (17) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.30 × 0.22 × 0.15 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
6110 measured reflections
2480 independent reflections
1912 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.053
wR(F ²) = 0.172
S = 1.09
2480 reflections
192 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812019630/ds2183sup1.cif

e-68-o1661-sup1.cif^{(21.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812019630/ds2183Isup2.hkl

e-68-o1661-Isup2.hkl^{(121.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812019630/ds2183Isup3.cml

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
N7—H7B⋯N3ⁱ	0.86	2.62	3.449 (5)	164
O9—H9⋯N8ⁱⁱ	0.82	2.12	2.829 (5)	145

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

Acknowledgments

MM would like to thank the University of Mysore for awarding a project under the head DV3/136/2007–2008/24.09.09.

supplementary crystallographic information

Comment

Pyrazole and its derivatives are a class of five-membered heterocyclic structure with two adjacent nitrogen atoms. These derivatives have drawn more attention in the field of current medicinal and pharmacological research; and reported to have a broad spectrum of biological activities, such as anti-inflammatory (Da Sliva et al., 2010), antitumor (Farag et al., 2010), analgesic (Khode et al., 2009), antimicrobial (Boschi et al., 2011), anticancer, radioprotective (Ghorab et al., 2010), antiamoebic (Husain et al., 2008), antioxidant (Taj et al., 2011) and antihypertensive (Mikhaylichenko et al., 2009). In addition, pyrazoles have gained prominent role in developing the theory of heterocyclic chemistry. With this potential and diverse background of pyrazole derivatives, we have synthesized the title compound to study its crystal structure.

In the molecule of the title compound (Fig. 1), the dihedral angles between the benzene at the N-(C10—C15) and α- position (C16—C21) of the pyrazole ring (C1/N1/N2/C4/C5) are 8.52 (13) and 9.26 (12)°, respectively. The dihedral angle between the two benzene rings is 1.86 (13)°. The central pyrazole moiety adopts a highly flattened envelope conformation with puckering parameter Q = 0.128 (2) Å and φ = 325.4 (10)° (Cremer & Pople, 1975), and the maximum deviation found on the puckered atom at C1 is 0.078 (8) Å. The carboximidamide unit is in syn-clinal conformation with respect to the pyrazole moiety, as indicated by the torsion angle value of 78.0 (2)°. Bond lengths (Allen et al., 1987) and bond angles agree with the observed values and are comparable to a related structure (Fun et al., 2011). The molecules are linked into centrosymetric dimers via O9–H9···N8 hydrogen bonds (Table 1) and further weak N—H···N interactions make these centrosymmetric dimer to form one-dimensional chain. The molecular packing exhibits layered stacking when viewd down the 'a' axis as shown in Fig. 2.

Experimental

A mixture of 1,3-diphenyl-4,5-dihydro-1H-pyrazole-5-carbonitrile (1.0 g,4.04 mmol), NH₂OH.HCl (0.3 g, 4.04 mmol) and sodium carbonate (0.43 g, 4.04 mmol) in 50% ethanol and water (20 ml) was warmed on a water bath for 4–5 h. The progress of the reaction was monitored by TLC. After completion of the reaction the solvent was evaporated in vacuum. Then the reaction mass was quenched into crushed ice and left over night. The solid obtained was filtered, washed with water, dried and recrystallized from ethanol(m.p=204–206°C).