Optimization of TopoIV Potency, ADMET Properties, and hERG Inhibition of 5-Amino-1,3-dioxane-Linked Novel Bacterial Topoisomerase Inhibitors: Identification of a Lead with <i>In Vivo</i> Efficacy against MRSA

Abstract

Novel bacterial topoisomerase inhibitors (NBTIs) are among the most promising new antibiotics in preclinical/clinical development. We previously reported dioxane-linked NBTIs with potent antistaphylococcal activity and reduced hERG inhibition, a key safety liability. Herein, polarity-focused optimization enabled the delineation of clear structure-property relationships for both microsomal metabolic stability and hERG inhibition, resulting in the identification of lead compound <b>79</b>. This molecule demonstrates potent antibacterial activity against diverse Gram-positive pathogens, inhibition of both DNA gyrase and topoisomerase IV, a low frequency of resistance, a favorable <i>in vitro</i> cardiovascular safety profile, and <i>in vivo</i> efficacy in a murine model of methicillin-resistant <i>Staphylococcus aureus</i> infection.