Synthesis and Biological Evaluation of Imadazo[1,2-a]pyrazines as Anticancer and Antiviral Agents through Inhibition of CDK9 and Human Coronavirus

In this work, novel imadazo[1,2-a]pyrazine derivatives were synthesized and evaluated as CDK9 inhibitors. The results of CDK9 assay showed that the derivatives with pyridin-4-yl in position 2 and benzyl in position 3 of imadazo[1,2-a]pyrazine 3c displayed the most potent CDK9 inhibitory activity with IC(50) of 0.16 µM. The anti-proliferative effect of the new compounds was examined against breast cancer (MCF7), colorectal cancer (HCT116), and chronic myelogenous leukaemia (K652) cell lines. The data of MTT assay showed that the cytotoxic effect of the inhibitors is correlated to their inhibitory activity against CDK9. Compound 3c exhibited the most potent cytotoxicity effect with average IC(50)s of three cell lines of 6.66 µM. The drug likeness properties of 3c were predicated in silico and demonstrated that 3c have reasonable physiochemical and pharmacokinetic properties. Selected derivatives were assessed in antiviral assay against human coronavirus 229E. The results of this assay showed that the derivative with pyridin-4-yl in position 2 and cyclohexyl in position 3 of imadazo[1,2-a]pyrazine 3b exhibited the most potent anti-coronaviral activity with IC(50) of 56.96 µM and selectivity index of 7.14. The target predication result revealed that 3b showed high affinity to protease enzyme. Docking studies of 3b with COVID-19 main protease was conducted and showed good binding affinity, which confirmed the in vitro assay data.