Copper-Catalyzed Synthesis of Functionalized Aryl Sulfonamides from Sodium Sulfinates in Green Solvents.

Functionalized aryl sulfonamides are important building blocks in the pharmaceutical industry. A one-step synthesis catalyzed by a copper salt was developed using stable solid commodity chemicals in sulfolane or, alternatively, in green solvents such as γ-valerolactone, iPrOAc, or nBuOAc with acetic acid. The method tolerated diverse functional groups commonly presented in current medicines and drug intermediates. The mechanistic study showed a radical coupling pathway between the sulfonyl and anilinium radicals through the use of K2S2O8 and copper catalyst, respectively.

Discovery of Inhibitors Targeting Protein-Protein Interaction between Bacterial RNA Polymerase and NusG as Novel Antimicrobials.

Bacterial RNA polymerase (RNAP), the core enzyme responsible for bacterial transcription, requires the NusG factor for efficient transcription elongation and termination. As the primary binding site for NusG, the RNAP clamp-helix (CH) domain represents a potential protein-protein interaction (PPI) target for novel antimicrobial agent design and discovery. In this study, we designed a pharmacophore model based on the essential amino acids of the CH for binding to NusG, such as R270, R278, and R281 (Escherichia coli numbering), and identified a hit compound with mild antimicrobial activity. Subsequent rational design and synthesis of this hit compound led to improved antimicrobial activity against Streptococcus pneumoniae, with the minimum inhibitory concentration (MIC) reduced from 128 to 1 µg/mL. Additional characterization of the antimicrobial activity, inhibitory activity against RNAP-NusG interaction, and cell-based transcription and fluorescent assays of the optimized compounds demonstrated their potential for further lead optimization.

Chan-Lam-Type C-S Coupling Reaction by Sodium Aryl Sulfinates and Organoboron Compounds.

A Chan-Lam-type C-S coupling reaction using sodium aryl sulfinates has been developed to provide diaryl thioethers in up to 92% yields in the presence of a copper catalyst and potassium sulfite. Both electron-rich and electron-poor sodium aryl sulfinates and diverse organoboron compounds were tolerated for the synthesis of aryl and heteroaryl thioethers and dithioethers. The mechanistic study suggested that potassium sulfite was involved in the deoxygenation of sulfinate through a radical process.