3,4-Dimethyl-1-phenyl­pyrano[2,3-c]pyrazol-6(1H)-one

Neman Ahmad; M Nawaz Tahir; Misbahul Ain Khan; Abdul Qayyum Ather; Muhammad Naeem Khan

doi:10.1107/S1600536811011317

. 2011 Mar 31;67(Pt 4):o1021. doi: 10.1107/S1600536811011317

3,4-Dimethyl-1-phenylpyrano[2,3-c]pyrazol-6(1H)-one

Neman Ahmad ^a, M Nawaz Tahir ^b,^*, Misbahul Ain Khan ^a, Abdul Qayyum Ather ^c, Muhammad Naeem Khan ^c

PMCID: PMC3099778 PMID: 21754037

Abstract

In the title compound, C₁₄H₁₂N₂O₂, the dihedral angle between the phenyl ring and the 3,4-dimethylpyrano[2,3-c]pyrazol-6(1H)-one system is 7.28 (6)°. An intramolecular C—H⋯O interaction generates an S(6) ring. In the crystal, the molecules are linked by C—H⋯O hydrogen bonds, forming C(8) chains. C–H⋯π and π–π interactions [centroid–centroid separation = 3.6374 (12) Å] further consolidate the packing.

Related literature

For a related structure, see: Ramsay & Steel (1985) ▶. For background to the pyrano[2,3-c]pyrazol-6-one ring system, see: Abdallah & Zaki (1999 ▶); Huang et al. (1992 ▶); Khan et al. (1982 ▶); Kuo et al. (1984 ▶); Ramsay & Steel (1985) ▶; Samaritoni et al. (2007 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₄H₁₂N₂O₂
M _r = 240.26
Monoclinic,
a = 15.1231 (9) Å
b = 13.3558 (8) Å
c = 13.8684 (8) Å
β = 120.965 (2)°
V = 2401.9 (3) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 296 K
0.35 × 0.25 × 0.25 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.975, T _max = 0.982
9214 measured reflections
2171 independent reflections
1382 reflections with I > 2σ(I)
R _int = 0.032

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.140
S = 1.02
2171 reflections
165 parameters
H-atom parameters constrained
Δρ_max = 0.15 e Å⁻³
Δρ_min = −0.19 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: ORTEP-3 for Windows (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811011317/hb5827sup1.cif

e-67-o1021-sup1.cif^{(17.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811011317/hb5827Isup2.hkl

e-67-o1021-Isup2.hkl^{(104.7KB, hkl)}

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

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

Cg3 is the centroid of the C1–C6 phenyl ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O2ⁱ	0.93	2.51	3.407 (3)	163
C6—H6⋯O1	0.93	2.29	2.938 (3)	126
C14—H14C⋯Cg3ⁱⁱ	0.96	2.75	3.506 (2)	136

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

Acknowledgments

The authors acknowledge the provision of funds for the purchase of the diffractometer and encouragement by Dr Muhammad Akram Chaudhary, Vice Chancellor, University of Sargodha, Pakistan. The authors also acknowledge the technical support provided by Bana International, Karachi, Pakistan.

supplementary crystallographic information

Comment

The parent ring system pyrano[2,3-c]pyrazol-6-one is an isostere of coumarin. A number of its derivatives have been prepared from corresponding hydrazines and beta ketoesters (Khan et al., 1982, Samaritoni et al., 2007). It has been shown that these contain analgesic and anti-inflammatory activities (Kuo et al., 1984, Abdallah & Zaki, 1999) and while others are tested for their antiplatelet activity (Huang et al., 1992). The title compound (I, Fig. 1) has been synthesized and its crystal structure is being reported here.

The crystal structure of (II) i.e., 3,4-dimethyl-1-(2-pyridyl)pyrano(2,3 - c)pyrazol-6(1H)-one (Ramsay & Steel, 1983) has been published which differs from (I) due to pyridal attachment instead of phenyl and hence is closely related.

In (I) the phyenyl ring A (C1–C6) and 3,4-dimethylpyrano[2,3-c]pyrazol -6(1H)-one moiety are almost planar with r. m. s. deviations of 0.003 and 0.023 Å, respectively. The dihedral angle between A/B is 7.28 (6)°. The molecules are linked by C(8) polymeric chains (Bernstein et al., 1995) due to H-boning of C—H···O type (Table 1, Fig. 2). An intramolecular H-bonding and a C—H···π interaction (Table 1) also play an important role in stabilizing the molecules. There also exist π···π interactions between the pyrazole rings at a distance of 3.6374 (12) Å.

Experimental

A mixture of 3-methyl-1-phenylpyrazol-5-one (17.4 g, 0.1 mol) and ethyl acetoacetate (13 g, 0.1 mol) was heated at 413 K (oil bath) for an hour, cooled and triturated with 200 ml of pet. ether (bp. 313–333 K) and filtered to give the title compound. Light brown rods of (I) were obtained on recrystallization from ethanol. Yield 10.8 g, 45%: m.p. 415 K