Carboxylic Anhydride Synthesis from γ-Benzyl-l-glutamate and Dimethyl Carbonate

A green, environmentally friendly, and nontoxic method was developed to synthesize carboxylic anhydrides (NCAs) from γ-benzyl-l-glutamate (BLG) and dimethyl carbonate (DMC) though two steps: synthesis of N-methoxycarbonyl-γ-benzyl-l-glutamate intermediate (NOM-BLG) and cyclization. The highest yields of NOM-BLG (up to 83.7%) and NCA-BLG (up to 66.7%) were obtained. Most importantly, the use of DMC will open an innovative door to synthesize NCAs.