7-Chloro-5-methyl-2-phenylpyrazolo[1,5-a]pyrimidine

The fused pyrazole and pyrimidine rings in the title compound, C13H10ClN3, are almost coplanar, their planes being inclined to one another by 0.8 (2)°. The mean plane of the fused ring system is nearly coplanar with the phenyl ring, as indicated by the dihedral angle between their planes of 9.06 (7)°.

The fused pyrazole and pyrimidine rings in the title compound, C 13 H 10 ClN 3 , are almost coplanar, their planes being inclined to one another by 0.8 (2) . The mean plane of the fused ring system is nearly coplanar with the phenyl ring, as indicated by the dihedral angle between their planes of 9.06 (7) .
The crystal structure of the title compound is built up from two fused five and six-membered rings (N1/N2/C4-C6 and N1/N3/C1-C4) linked to a methyl group and to a phenyl ring (C7-C12) as shown in Fig. 1. The pyrazole and pyrimidine rings are essentially planar with maximum deviations of 0.0010 (13) Å and 0.0052 (13) Å for C6 and C1, respectively, and form a dihedral angle of 0.8 (2)°. The mean plane through the fused ring system makes a dihedral angle of 9.06 (7)° with the phenyl ring.
The reaction mixture was allowed to cool to room temperature. After evaporation of the solvent under reduced pressure and addition of a NaHCO 3 saturated solution at 273 K (pH = 8), the residue was extracted with CH 2 Cl 2 . The combined organic layers were dried with MgSO 4 , concentrated under vacuum and the residue was purified on silica gel by column chromatography using a 9:1 (v/v) mixture of petroleum ether and ethyl acetate as eluent. The compound was recrystallized from a mixture of cyclohexane/CH 2 Cl 2 (1:1 v/v) to give colourless crystals.

Refinement
All H atoms could be located in a difference Fourier map and treated as riding with C-H = 0.93 Å (aromatic), and C-H = 0.96 Å (methyl) and with U iso (H) = 1.2 U eq (aromatic) or U iso (H) = 1.5 U eq (methyl).

7-Chloro-5-methyl-2-phenylpyrazolo[1,5-a]pyrimidine
Crystal data 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 0.07651 (