Design, synthesis and evaluation of pyrazole derivatives as non-nucleoside hepatitis B virus inhibitors

In continuation of our efforts toward the discovery of potent non-nucleoside hepatitis B virus (HBV) inhibitors with novel structures, we have employed bioisosterism and hybrid pharmacophore-based strategy to explore the chemically diverse space of bioactive compounds. In this article, the original thiazole platform was replaced with pyrazole scaffold to yield the optimal pharmacophore moieties in order to generate novel non-nucleoside HBV inhibitors with desirable potency. Some of the new compounds were able to inhibit HBV activity in the low micromolar range. In particular, compound 6a3 displayed the most potent activity against the secretion of HBsAg and HBeAg with IC50 of 24.33 μM and 2.22 μM, respectively. The preliminary structure-activity relationship (SAR) of this new series of compounds was investigated, which may help designing more potent molecules.