cis,cis,cis-1,2,4,5-cyclohexanetetracarboxylic acid and its dianhydride

cis,cis,cis-1,2,4,5-Cyclohexanetetracarboxylic acid,C10H12O8, (I), contains a mirror plane and the cyclohexane ring exhibits a chair conformation. Two crystallographically independent hydrogen bonds form R-2(2)(14), R-2(2)(16) and R-4(4)(16) ring motifs, and propagation of these two hydrogen bonds along the c and b axes generates C-2(2)(16) and C-2(2)(7) chains. cis, cis, cis-1,2: 4,5-Cyclohexanetetracarboxylic dianhydride, C10H8O6, (II), was prepared by the reaction of (I) with acetic anhydride. The cyclohexane ring of (II) exhibits a boat conformation and the dihedral angle between the two anhydro rings is 117.5 (1)degrees.