Synthesis, anticancer activity, and molecular docking of new pyrazolo[1,5-a]pyrimidine derivatives

The reaction of 3-aminopyrzoles with dimethylamino-acrylonitrile derivatives was utilized for the production of new functionalized pyrazolopyrimidine compounds 4a-c and 6a-c. The structures of the obtained pyrazolopyrimidines were characterized by the different spectroscopic measurements (IR, NMR, and mass analyses). The DFT quantum chemical calculations were applied to the determination of the HOMO-LUMO energies and Mulliken atomic charges. The investigated derivatives exhibited a low HOMO-LUMO energy gap, ranging from 2.70 to 2.34 eV, 4c and both 4b and 6b, respectively. Furthermore, the anticancer activities of the synthesized compounds have also been investigated against four cancer cells as well as normal cells (WI38). The investigated compounds demonstrated an impressive cytotoxic effect on MCF-7 and Hep-2 cells. On comparison with 5-fluorouracil, pyrazolopyrimidines 6a–c showed promising cytotoxic action against MCF-7 and Hep-2, with IC50 values of 18.31–26.51 and 24.15–27.16 μM, respectively. Molecular docking of the prepared pyrazolopyrimidines 4 and 6 with the crystal structure of the KDM5A protein, obtained from the PDB, revealed the types of the protein's binding sites.