Design of Substituted Imidazolidinylpiperidinylbenzoic Acids as Chemokine Receptor 5 Antagonists: Potent Inhibitors of R5 HIV‑1 Replication

The redesign of the previously reported thiophene-3-yl-methyl urea series, as a result of potential cardiotoxicity, was successfully accomplished, resulting in the identification of a novel potent series of CCR5 antagonists containing the imidazolidinylpiperidinyl scaffold. The main redesign criteria were to reduce the number of rotatable bonds and to maintain an acceptable lipophilicity to mitigate hERG inhibition. The structure–activity relationship (SAR) that was developed was used to identify compounds with the best pharmacological profile to inhibit HIV-1. As a result, five advanced compounds, <b>6d</b>, <b>6e</b>, <b>6i</b>, <b>6h</b>, and <b>6k</b>, were further evaluated for receptor selectivity, antiviral activity against CCR5 using (R5) HIV-1 clinical isolates, and in vitro and in vivo safety. On the basis of these results, <b>6d</b> and <b>6h</b> were selected for further development