Button-Push On-Demand Synthesis for Rapid Optimization of Antiviral Peptidomimetics.

The optimization of hit compounds into drug candidates is a pivotal phase in drug discovery but often hampered by cumbersome manual synthesis of derivatives. While automated organic molecule synthesis has enhanced efficiency, safety, and cost-effectiveness, achieving fully automated multistep synthesis remains a formidable challenge due to issues such as solvent and reagent incompatibilities and the accumulation of side-products. We herein demonstrate an automated solid-phase flow platform for synthesizing α-keto-amides and nitrile peptidomimetics, guided by docking simulations, to identify potent broad-spectrum antiviral leads. A compact parallel synthesizer was built in-house, capable of producing 5 distinct molecules per cycle; 525 reactions could be finished within three months to generate 42 derivatives for a structure-activity relationship (SAR) investigation. Among these, ten derivatives exhibited promising target inhibitory activity (IC < 100 nM) including two with antiviral activity (EC < 250 nM). The platform, coupled with digital chemical recipe files, offers rapid access to a wide range of peptidomimetics, serving as a valuable reservoir for broad-spectrum antiviral candidates. This automated solid-phase flow synthesis approach expedites the generation of previously difficult complex molecular scaffolds. By integration of SPS-flow synthesis with medicinal chemistry campaign, >10-fold target inhibitory activity was achieved from a small set of derivatives, which indicates the potential to shift the paradigm of drug discovery.