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

Article abstract of DOI:10.1107/S0108270103013362

Cis,cis,cis-l,2,4,5-CyclohexanetetracarboxyIic acid, C₁₀H ₁₂O₈, (I), contains a mirror plane and the cyclohexane ring exhibits a chair conformation. Two crystallographically independent hydrogen bonds form R₂²(14), R₂²(16) and R₄⁴(16) ring motifs, and propagation of these two hydrogen bonds along the c and b axes generates C₂²(16) and C₂²(7) chains. cis,cis,cis-l,2:4,5-Cyclohexanetetracarboxylic dianhydride, C₁₀H ₈O₆, (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)°.