(4-Chlorophenyl)[1-(4-methoxyphenyl)-3-(5-nitro-2-furyl)-1H-pyrazol-4-yl]methanone

In the title compound, C21H14ClN3O5, an intramolecular C—H⋯O hydrogen bond generates an S(7) ring motif and the furan and pyrazole rings are almost coplanar, making a dihedral angle of 1.98 (5)°. The pyrazole ring is inclined at dihedral angles of 47.59 (4) and 7.27 (4)° to the chlorophenyl and methoxyphenyl groups, respectively. The nitro group is almost coplanar to its attached furan ring [dihedral angle = 2.03 (12)°]. In the crystal, intermolecular C—H⋯O hydrogen bonds link the molecules into a three-dimensional network. The crystal structure also features short intermolecular O⋯N [2.8546 (12) Å] and Cl⋯O [3.0844 (9) Å] contacts as well as aromatic π–π stacking interactions [centroid–centroid distance = 3.4367 (6) Å].


Comment
The pyrazole nucleus constitutes an interesting class of organic compound with diverse chemical applications. They possess anti-pyretic, anti-tumor, tranquilizing and herbicidal activities. Sydnones are easily accessible aromatic compounds and versatile synthetic intermediates with a masked azomethine imine unit. The 1,3-dipolar cycloaddition reaction with various dipolarophiles offers a convenient synthetic route for the preparation of pyrazole derivatives and has been studied extensively Rai et al., 2008). The incorporation of 5-nitrofuran moiety into various heterocyclic systems has found to increase their biological activities. We have reported a few heterocyclic systems carrying 5-nitrofuran moiety as potent anti-microbial agents (Hedge et al., 2006). In continuation of our studies on 1,3-dipolar cycloaddition reactions of sydnones with dipolarphiles carrying nitrofuran moiety (Kalluraya et al., 1994), we herein report the crystal structure of the above pyrazole compound.
Experimental 3-(p-Anisyl)sydnone (0.01 mol) and 1-(p-chlorophenyl)-3-(5-nitro-2-furyl)-2-propyn-1-one (0.01 mol) were dissolved in dry xylene (10 ml) and refluxed for 4 h. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The crude product obtained was purified by recrystallization from a mixture of ethanol and DMF. The solid obtained was collected by filtration, washed with ethanol and dried. Orange blocks of (I) were obtained from a 1:2 mixture of ethanol and DMF by slow evaporation.
supplementary materials sup-2 Refinement All the hydrogen atoms were placed in their calculated positions, with C-H = 0.93 or 0.96 Å, and refined using a riding model with U iso = 1.2 or 1.5 U eq (C). A rotating group model was used for the methyl group. Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids for non-H atoms. An intramolecular hydrogen bond is shown as dashed line.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1)K.
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.