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 mu M, respectively). Additionally, these compounds did not exhibit significant toxicity (CC50 > 200 mu M in CEF cells; CC50 > 250 mu M in MDCK cells). These findings highlight 27c and 33c as promising next-generation anti-influenza agents.