Copper-Catalyzed Electrophilic Amination of Benzoxazoles via Magnesation

Proline selective labeling via on-site construction of naphthoxazole (NapOx)

Chemoselective construction of naphthoxazoles (NapOx) via a three-component annulation reaction enables proline selective labeling of peptides in solution or in solid-phase synthesis. The fluorogenic peptides possess low cytotoxicity, efficient cell membrane permeability and excellent bioimaging potential for biomedical applications.

Synthesis of Various 2-Aminobenzoxazoles: The Study of Cyclization and Smiles Rearrangement

This study reports two synthetic approaches leading to 2-aminobenzoxazoles and their N-substituted analogues. Our first synthetic strategy involves a reaction between various o-aminophenols and N-cyano-N-phenyl-p-toluenesulfonamide as a nonhazardous electrophilic cyanating agent in the presence of Lewis acid. The second synthetic approach uses the Smiles rearrangement upon activation of benzoxazole-2-thiol with chloroacetyl chloride. Both developed synthetic protocols are widely applicable, afford the desired aminobenzoxazoles in good to excellent yields, and use nontoxic and inexpensive starting material.