Elaborate Structural Modifications Yielding Novel Boron-Containing N-Substituted Oseltamivir Derivatives as Potent Neuraminidase Inhibitors with Significantly Improved Broad-Spectrum Antiresistance Profiles

Inspired by our previous finding that targeting the 150-cavity with a multisite-binding strategy emerged as an effective approach to obtain more potent and selective neuraminidase (NA) inhibitors against Influenza Virus, we present here the design, synthesis, and optimization of novel boron-containing N-substituted oseltamivir (OSC) derivatives. Exploratory structure-activity relationship (SAR) studies led to the identification of compounds 27c and 33c as the most potent NA inhibitors, surpassing OSC in potency against both wild-type group-1 NAs and oseltamivir-resistant NAs. These compounds demonstrated significant Antiviral activity against several wild-type strains and H1N1pdm09 strains (EC₅₀ = 0.03 ± 0.005 and 0.03 ± 0.0008 μM, respectively). Additionally, these compounds did not exhibit significant toxicity (CC₅₀ > 200 μM in CEF cells; CC₅₀ > 250 μM in MDCK cells). These findings highlight 27c and 33c as promising next-generation anti-influenza agents.