Concerted general acid catalysis in the reaction of acetate ion with water-soluble carbodi-imide

Abstract

An intermediate, identified as an O-acetylisourea, is observed spectroscopically in the reaction of a water-soluble carbodi-imide with acetate buffers; a stepwise mechanism for intermediate formation as currently accepted is excluded by the observation of general acid catalysis, while acetate ion attack on carbodi-imide is concerted with proton transfer, and monoanions of dicarboxylic acids react with carbodi-imide with intramolecular concerted proton transfer.