Synthesis-Stuttgart, vol. 2003, no. 10, pp. 1517-1520
A novel and facile synthesis of carboxylic anhydrides from carboxylic acid using 4,5-dichloro-2-[(4-nitrophenyl)sulfonyl]pyridazin-3(2H)-one (2) is presented. Treatment of aliphatic or aromatic carboxylic acids with 2 in the presence of base in organic solvents gave the corresponding anhydrides in good or excellent yields.