Design, synthesis and biological evaluation of novel 5-phenyl-1H-pyrazole derivatives as potential BRAFV600E inhibitors

Abstract A series of novel 5-phenyl-1 H -pyrazole derivatives ( 5a – 5u ) containing niacinamide moiety were synthesized and evaluated for biological activity as potential BRAF V600E inhibitors. Among them, compound 5h exhibited the most potent inhibitory activity with an IC 50 value of 0.33 μM for BRAF V600E . Antiproliferative assay results indicated that compound 5h has better antiproliferative activity against WM266.4 and A375 in vitro with IC 50 value of 2.63 and 3.16 μM, respectively, being comparable with the positive control vemurafenib. Molecular docking of 5h into the BRAF V600E active site was performed to determine the probable binding mode. Furthermore, molecular docking and 3D QSAR study by means of DS 3.5 (Discovery Studio 3.5, Accelrys, Co. Ltd) explored the binding modes and the structure and activity relationship (SAR) of these derivatives.