Discovery of 4‐Quinazolinone‐Containing Phenylalanine Derivatives as Potent, Resistant‐Tolerant HIV Capsid Inhibitors

The HIV‐1 capsid (CA) is a validated antiviral target that plays critical roles in both the early and late stages of the viral life cycle. Using structure‐based strategy, we designed and synthesized a series of phenylalanine derivatives containing a 4‐quinazolinone scaffold as novel HIV‐1 CA inhibitors. Among them, IC‐2i exhibited potent antiviral activity in MT‐4 cells against HIV‐1 NL4‐3 (EC 50 = 0.65 ± 0.27 nM) and effectively protected cells from HIV‐1 IIIB infection. SPR revealed that IC‐2i interacts strongly with CA hexamers ( K D = 2.7 ± 0.5 nM) with an extended residence time and competes with host factors CPSF6 and NUP153, disrupting CA assembly and disassembly. IC‐2i retained activity against lenacapavir (LEN)‐resistant strains, such as N74D (11‐fold shift vs. 20‐fold for LEN). Crystallographic analysis revealed that IC‐2i binds at the CA NTD–CTD interface and forms hydrogen bonds with Thr107 and Ser41 (NTD–NTD interface). Pharmacological evaluation demonstrated favorable properties, including good plasma stability, low toxicity (SI > 1571), and suitable pharmacokinetics with a prolonged half‐life following subcutaneous administration ( T 1/2 = 19.9 h). Overall, this study identifies 4‐quinazolinone‐based phenylalanine derivatives as promising HIV‐1 CA inhibitors and highlights IC‐2i as a potential long‐acting therapeutic candidate for HIV‐1 treatment.