Enantioselective Construction of C3-Multifunctionalization α-Hydroxy-β-amino Pyridines via α-Pyridyl Diazoacetate, Water, and Imines for Drug Hunting

Novel Alkynylamide-Based Nonpeptidic Allosteric Inhibitors for SARS-CoV-2 3-Chymotrypsin-like Protease

Although the coronavirus disease 2019 (COVID-19) crisis has passed, there remains a necessity for continuous efforts toward developing more targeted drugs and preparing for potential future virus attacks. Currently, most of the drugs received authorization for the treatment of COVID-19 have exhibited several limitations, such as poor metabolic stability, formidable preparation, and uncertain effectiveness. It is still significant to develop novel, structurally diverse small-molecule antiviral drugs targeting SARS-CoV-2 3-chymotrypsin-like protease (3CLpro). Herein, we report a class of alkynylamide-based nonpeptidic 3CLpro inhibitors that can be prepared conveniently by our previously developed one-pot synthetic method. The structure-activity relationships of alkynylamides as SARS-CoV-2 3CLpro inhibitors have been carefully investigated and discussed in this study. The two stereoisomers of the resulting molecules exhibit stereoselective interaction with 3CLpro, and the optimized compound (S,R)-4y inhibits 3CLpro with high potency (IC50 = 0.43 μM), low cytotoxicity, and acceptable cell permeability. Compound (S,R)-4y presents as a noncovalent inhibitor of 3CLpro against SARS-CoV-2 by the time-dependent inhibition assay (TDI) and mass spectrometry analysis. The Lineweaver-Burk plots, binding energy, surface plasmon resonance, and molecular docking studies suggest that (S,R)-4y specifically binds to an allosteric pocket of the SARS-CoV-2 3CLpro. These findings provide a novel class of nonpeptidic alkynylamide-based allosteric inhibitors with high selectivity against SARS-CoV-2 3CLpro featured by a simplified one-pot synthesis at room temperature in air.

Discovery of potent thiazolidin-4-one sulfone derivatives for inhibition of proliferation of osteosarcoma in vitro and in vivo

Chemotherapy combining with surgical treatment has been the main strategy for osteosarcoma treatment in clinical. Due to unclear pathogenesis and unidentified drug targets, significant progress has not been made in the development of targeted drugs for osteosarcoma during the past 50 years. Our previous discovery reported compound R-8i with a high potency for the treatment of osteosarcoma by phenotypic screening. However, both the metabolic stability and bioavailability of R-8i are poor (T1/2 = 5.36 min, mouse liver microsome; and bioavailability in vivo F = 52.1 %, intraperitoneal administration) which limits it use for further drug development. Here, we described an extensive structure-activity relationship study of thiazolidine-4-one sulfone inhibitors from R-8i, which led to the discovery of compound 68. Compound 68 had a potent cellular activity with an IC50 value of 0.217 μM, much higher half-life (T1/2 = 73.8 min, mouse liver microsome) and an excellent pharmacokinetic profile (in vivo bioavailability F = 115 %, intraperitoneal administration). Compound 68 also showed good antitumor effects and low toxicity in a xenograft model (44.6 % inhibition osteosarcoma growth in BALB/c mice). These results suggest that compound 68 is a potential drug candidate for the treatment of osteosarcoma.