Discovery of 3,4-dihydropyrimidine derivatives as novel Anti-PEDV agents targeting viral internalization through a unique calcium homeostasis disruption mechanism

Abstract

Porcine epidemic diarrhea virus (PEDV) poses critical challenges to global swine production, with current vaccines showing limited efficacy against emerging strains. To address this gap, we designed 41 novel 3,4-dihydropyrimidine derivatives via systematic structure-activity relationship (SAR) optimization. Compound D39, incorporating a C-4 2′-substituted biphenyl, C-2 thione, C-6 phenyl, and C-5 isopropanol substituents, emerged as the most potent anti-PEDV agent (EC₅₀ = 0.09 μM, SI = 358.9), outperforming remdesivir (EC₅₀ = 3.14 μM, SI > 40.8) by 35-fold. D39 exhibited broad-spectrum anti-coronavirus activity (FIPV, IDV) at micromolar levels and demonstrated acceptable metabolic stability (T_1/2 = 78.75 min, Cl_int = 8.8 μL/min/mg) in porcine liver microsomes. Mechanistic studies revealed the antiviral actions was achieved by blocking PEDV early internalization via intracellular Ca²⁺ homeostasis modulation. These findings highlight D39 as a first-in-class anti-PEDV candidate with a unique dihydropyrimidine scaffold and a calcium-targeting mechanism, offering a promising therapeutic strategy against coronaviral infections.