Synthesis and Biological Evaluation of N‐Substituted Sophocarpinic Acid Derivatives as Coxsackievirus B3 Inhibitors

A series of novel N-substituted sophocarpinic acid derivatives was designed, synthesized, and evaluated for their anti-enteroviral activities against coxsackievirus type B3 (CVB3) and coxsackievirus type B6 (CVB6) in Vero cells. Structure-activity relationship analysis revealed that the introduction of a benzenesulfonyl moiety on the 12-nitrogen atom in (E)-β,γ-sophocarpinic acid might significantly enhance anti-CVB3 activity. Among the derivatives, (E)-12-N-(m-cyanobenzenesulfonyl)-β,γ-sophocarpinic acid (11 m), possessing a meta-cyanobenzenesulfonyl group, exhibited potent activity against CVB3 with a selectivity index (SI) of 107. Furthermore, compound 11 m also showed a good oral pharmacokinetic profile, with an AUC value of 7.29 μM h⁻¹ in rats, and good safety through the oral route in mice, with an LD₅₀ value of >1000 mg kg⁻¹; these values suggest a druggable characteristic. Therefore, compound 11 m was selected for further investigation as a promising CVB3 inhibitor. We consider (E)-β,γ-N-(benzenesulfonyl)sophocarpinic acids to be a novel class of anti-CVB3 agents.