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
4,5-dichloro-2-[4-nitrophenyl)sulfonyl]pyridazin-3(2H)-one - carboxylic anhydride - sulfonyl-transfer