Synthesis, Crystal Structure and Biological Activity of 7-(4-Methylpiperazin-1-Yl)-5-[4-(Trifluoromethyl)Phenyl]pyrazolo[1,5-a]Pyrimidine-3-Carbonitrile

The title compound C19H17F3N6 was synthesized and structurally characterized by infrared and mass spectroscopy, 1H NMR, elemental analyses and single crystal X-ray diffraction. The compound crystallizes in monoclinic system, space group P21/c with a = 17.097(4) Å, b = 7.1668(16) Å, c = 18.389(3) Å, β = 118.251(15)°, V = 1984.8(8) Å3, Z = 4, Dc = 1.293 g cm–3, F(000) = 800, μ(MoKα) = 0.10 mm–1, R1 = 0.0667, and wR2 = 0.2084 for reflections with I > 2σ(I). Pyrazolo[1,5-a]pyrimidine and phenyl ring are almost coplanar, and the piperazine ring is in a chair conformation. The crystal structure is stabilized by C–H⋅⋅⋅N hydrogen interactions and a number of weak π⋅⋅⋅π interactions. In addition, the results of the determination of biological activity showed that the compound exhibited significant inhibitory activity against K562 and MKN45 cancer cell lines.