A two-step, one-pot synthesis of diverse N-pyruvoyl amino acid derivatives using the Ugi reaction

A 100-member combinatorial library of α-ketoamides, which was designed to search potent cysteine protease inhibitors, was generated by a parallel solution-phase synthesis. A two-step one-pot synthesis, in which the Ugi reaction followed by pyridinium dichromate (PDC) oxidation was employed in the same reaction vessel, easily afforded the α-ketoamides in a short time.