1,1'-Biphenyl-2,3',3,4'-tetracarboxylic acid → [4,5'-Biisobenzofuran]-1,1',3,3'-tetrone

Participants

Reaction Steps

Acetic anhydride (400 ml.) was added to 116 g of 2,3,3',4'-biphenyltetracarboxylic acid having a melting point of 195° to 205°C., and the mixture was heated under reflux for 4 hours. The mixture was cooled, and allowed to stand. The crystals formed were filtered to provide 83 g (yield 80% of theoretical) of 2,3,3',4'-biphenyltetracarboxylic dianhydride having a melting point of 196° to 204°C. By further concentration of the filtrate, 17 g (16%) of 2,3,3',4'-biphenyltetracarboxylic dianhydride was obtained.

Provenance & Evidence