[S:1]1[CH:5]=[C:4]([C:6]([OH:8])=O)[C:3]([C:9]([OH:11])=[O:10])=[CH:2]1>C(OC(=O)C)(=O)C>[S:1]1[CH:2]=[C:3]2[C:9]([O:11][C:6](=[O:8])[C:4]2=[CH:5]1)=[O:10]Thiophene-3,4-dicarboxylic acid (12 g, 0.07 mol) is dissolved in acetic anhydride (60 ml) and boiled for 2.5 hours. The mixture is then concentrated to dryness. There is obtained 10.55 g (98%) of thiophene-3,4-dicarboxylic anhydride (m.p. 147°-149° C.).
Wird geladen…