Modification, Biological Evaluation and SAR Studies of Novel 1H-Pyrazol Derivatives Containing N,N'-Disubstituted Urea Moiety as Potential Anti-melanoma Agents.

Malignant melanomas are amongst the most aggressive cancers. BRAF Inhibitors have exhibited therapeutic effects against BRAF-mutant melanoma. In continuation of our earlier studies on anti-melanoma agents based on 1H-pyrazole skeleton, two sets of novel compounds that include 1H-pyrazole-4-amines FA1 - FA13 and corresponding urea derivatives FN1 - FN13 have been synthesized and evaluated for their BRAF inhibitory and antiproliferation activities. Compound FN10 displayed the most potent biological activity against BRAF (IC = 0.066 μm) and the A375 human melanoma cell line (GI = 0.81 μm), which was comparable to the positive control vemurafenib, and more potent than our previously reported 1H-pyrazole-3-amines and their urea derivatives. The results of SAR studies and molecular docking can guide further optimization and may help to improve potency of these pyrazole-based anti-melanoma agents.