Kyowa Hakko Kogyo Kabushiki Kaisha

Tatsuo Nomura

Yasuo Fujimoto

Keizo Tatsukawa

Shohei Kobayashi

Yoichi Koiwa

Akira Miike

This invention relates to an improved process for preparing N-carboxylic anhydrides of amino acids, and N-carboxylic anhydrides of derivatives of amino acids by reacting an amino acid, a derivative of amino acid or a salt thereof with trichloromethylchloroformate in an organic solvent, preferably a mixture of an ether or ester with one or more other organic solvents and adding to the reaction mixture carbon, basic aluminum chloride or aluminum oxide just before or immediately after completion of the initial reaction.

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Tokyo, Japan

Tatsuo Nomura