1-[(3,5-Dimethyl-1H-pyrazol-1-yl)carbonyl]-5-methylindolizine-3-carbonitrile

In the title molecule, C16H14N4O, the indolizine ring system is essentially planar, with a maximum deviation of 0.013 (3) Å, and forms a dihedral angle of 7.52 (12)° with the pyrazole ring. In the crystal, weak C—H⋯O hydrogen bonds and π–π stacking interactions, with a centroid–centroid distance of 3.6378 (16) Å, link molecules along [001].

In the title molecule, C 16 H 14 N 4 O, the indolizine ring system is essentially planar, with a maximum deviation of 0.013 (3) Å , and forms a dihedral angle of 7.52 (12) with the pyrazole ring. In the crystal, weak C-HÁ Á ÁO hydrogen bonds andstacking interactions, with a centroid-centroid distance of 3.6378 (16) Å , link molecules along [001].

Comment
Indolizines and pyrazoles are important classes of bio-active drug targets in the pharmaceutical industry, as they are the core structure of numerous biologically active compounds (Tukulula et al., 2010;James et al., 2008;Teklu et al., 2005;McDonald et al., 2006;Jagerovic et al., 2002). In our continuing studies on the synthesis and properties of heterocycles (Gu et al., 2011;Shen et al., 2008;Shen et al., 2006;Wang, et al., 2000) we have prepared ( Fig. 1) and determined the crystal structure of the title compound.

Refinement
H atoms were placed in calculated positions and allowed to ride, with C-H = 0.93 and 0.96Å and U iso (H) = 1.2U eq (C) or 1.2U eq (C methyl ). The distance for C8-C9 was restrained with the command DFIX 1.4 0.01 C8 C9 in SHELXL (Sheldrick, 2008

Figure 1
The reaction scheme.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1 0.4078 (