6-Amino-3,4-dimethyl-4-phenyl-2H,4H-pyrano[2,3-c]pyrazole-5-carbonitrile

Nishith Saurav Topno; Kandhasamy Kumaravel; M Kannan; Gnanasambandam Vasuki; R Krishna

doi:10.1107/S1600536811009354

. 2011 Mar 23;67(Pt 4):o956. doi: 10.1107/S1600536811009354

6-Amino-3,4-dimethyl-4-phenyl-2H,4H-pyrano[2,3-c]pyrazole-5-carbonitrile

Nishith Saurav Topno ^a, Kandhasamy Kumaravel ^b, M Kannan ^a, Gnanasambandam Vasuki ^b, R Krishna ^a,^*

PMCID: PMC3099764 PMID: 21754221

Abstract

In the title compound, C₁₅H₁₄N₄O, the pyrazole ring is aligned at 88.23 (4)° with respect to the aromatic ring and at 3.75 (4)° with respect to the pyran ring. In the crystal, N—H⋯N hydrogen bonds link adjacent molecules into a linear chain motif. C—H⋯N interactions are also observed.

Related literature

For the synthesis, see: Vasuki & Kumaravel (2008 ▶). For the use of related compounds in organic synthesis, see: Liang et al. (2009 ▶). For related structures, see: Kannan et al. (2010 ▶).

Experimental

Crystal data

C₁₅H₁₄N₄O
M _r = 266.3
Triclinic,
a = 6.682 (5) Å
b = 9.347 (5) Å
c = 11.078 (5) Å
α = 99.213 (5)°
β = 102.740 (5)°
γ = 97.767 (5)°
V = 655.6 (7) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.22 × 0.20 × 0.16 mm

Data collection

Bruker APEXII Kappa CCD detector diffractometer
18424 measured reflections
4996 independent reflections
3169 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.057
wR(F ²) = 0.173
S = 0.99
4996 reflections
183 parameters
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: APEX2 and SAINT (Bruker, 2004 ▶); data reduction: SAINT and XPREP (Bruker, 2004 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811009354/ng5120sup1.cif

e-67-0o956-sup1.cif^{(18.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811009354/ng5120Isup2.hkl

e-67-0o956-Isup2.hkl^{(244.7KB, 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
N3—H3A⋯N1ⁱ	0.86	2.27	3.129 (2)	173
N3—H3B⋯N4ⁱⁱ	0.86	2.26	3.087 (2)	160
C10—H10⋯N4ⁱⁱⁱ	0.93	2.53	3.455 (3)	172
C14—H14A⋯N1^iv	0.96	2.59	3.522 (3)	163

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

Acknowledgments

The authors acknowledge the Centre of Excellence in Bioinformatics, Pondicherry University, for providing the facilities for carrying out this work. RK and MK thank the University Grant Commission for providing a Major Research Project and Rajiv Gandhi National Fellowship, respectively. GV thanks the Department of Science and Technology, New Delhi, Government of India (grant No. SR/S5/GC-22/2007) for financial support.

supplementary crystallographic information

Comment

The pyrano pyrazole derivatives are widely used as organic intermediates (Liang et al., 2009) and are well known for their biological contribution as ChK1 inhibitors. In view of the growing importance of the pyrano pyrazole derivatives, we have synthesized the title compound by Rapid four-component reactions in water (Vasuki & Kumaravel, 2008) and the single-crystal structure analysis was undertaken.

In the title compound, the attached benzyl ring makes the dihedral angle of 88.23 (4) ° and orient in (+)-syn-clinal conforamtion with pyrazole ring, whereas the fused pyrazole ring makes 3.75 (4) ° dihedral angle and orient by an (+)-syn-periplanar conformation with respect to the pyran ring (Fig. 1). The methyl group is attached to C6 atom of pyran with an angle of 109.29 (11) °. Two N—H···N and C—H···N intermolecular hydrogen bond interactions (Fig. 2) are observed for maintaining the crystal packing (Fig. 3), in which the N3—H···N4 intermolecular interaction are observed to form R₂² (12) ring motifs (Fig. 4). The weak N—H···π intermolecular interaction is also observed for the stabilization of the crystal packing, with a bond distance of 3.382 (3) Å (Fig. 5).

Experimental

The title compound was prepared by the successive addition of acetophenone 2 (0.240 g, 2 mmol), malononitrile (0.132 g, 2 mmol) and piperidine (5 mol%) to a stirred aqueous mixture of hydrazine hydrate 96% 1 (0.107 g, 2 mmol) and ethyl acetoacetate 2 (0.520 g, 2 mmol) at room temperature under an open atmosphere with vigorous stirring for 5–10 min. The precipitated solid was then filtered, followed by washing with water and then with a mixture of ethyl acetate/hexane (20:80). The product obtained was pure by TLC and 1H NMR spectroscopy. Nevertheless, the products were further purified by recrystallization from ethanol. Analysis calculated for 6-amino-3,4-dimethyl-4-phenyl-2H,4H-pyrano[2,3-c]pyrazole-5-carbonitrile showed that it has C₁₅H₁₄N₄O.