Base-Mediated Synthesis of Anhydrides from Activated Amides.

Symmetrical anhydrides were synthesized from activated amides such as N-benzoylsaccharins and N-Boc-protected benzamides. The activated amides reacted with H2O in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) at 25 °C to produce the corresponding symmetrical anhydrides in high yields through C-N bond cleavage. In addition, N-benzoylsaccharins reacted with benzoic acid derivatives to generate unsymmetrical anhydrides in high yields.