Discovery of orally bioavailable N-acylated remdesivir derivatives with potent broad-spectrum antiviral activity.

Remdesivir (RDV), a nucleoside analog targeting viral RNA-dependent RNA polymerase (RdRp), suffers from critical limitations including low oral bioavailability, plasma instability, and reliance on intravenous administration, hindering its clinical utility. To address these issues, we designed and synthesized 28 novel N-acylated derivatives by modifying the amino group on remdesivir's triazine ring. The lead compound 4f exhibited potent anti-SARS-CoV-2 activity (EC50 = 0.0862 μM) in Vero E6 cells, comparable to remdesivir (EC50 = 0.0459 μM), with reduced cytotoxicity (CC50 = 15.6 μM, SI = 181.0). Notably, 4f displayed broad-spectrum efficacy against human coronaviruses (HCoV-229E and HCoV-OC43), zika virus (ZIKV), and yellow fever virus (YFV), matching remdesivir's potency. Pharmacologically, 4f showed significantly enhanced plasma stability (half-life >8 h vs. 2 h for RDV) and reduced CYP3A4 inhibition (23.8% vs. 57.4% for RDV at 10 μM). In vivo pharmacokinetics confirmed its superior oral bioavailability (45.3% based on active metabolite GS-441524 exposure), efficiently delivering GS-441524 into systemic circulation. This N-acylation strategy overcomes key pharmacokinetic barriers of remdesivir while preserving broad-spectrum antiviral activity, highlighting 4f as a promising oral candidate.