A new series of propionamide derivatives was developed as dual μ-opioidreceptoragonists and σ1 receptor antagonists. Modification of a high-throughput screening hit originated a series of piperazinylcycloalkylmethyl propionamides, which were explored to overcome the challenge of achieving balanced dual activity and convenient drug-like properties. The lead compound identified, 18g, showed good analgesic
A New Strategy To Improve the Metabolic Stability of Lactone: Discovery of (20<i>S</i>,21<i>S</i>)-21-Fluorocamptothecins as Novel, Hydrolytically Stable Topoisomerase I Inhibitors
was validated by the discovery of (20S,21S)-21-fluorocamptothecins as hydrolytically stable topoisomerase Iinhibitors. A highly potent camptothecin derivative, 8l, was successfully identified, which showed excellent in vitro and in vivo antitumor activities and represents a promising lead for the discovery of novel antitumor agents. Interestingly, this study also provided a new structure–activity