STRUCTURAL STUDIES OF SOME DERIVATIVES OF CIS, CIS-CYCLOHEXANE-1,3,5-TRICARBOXYLIC ACID
Chan, TL; Cui, YX; Mak, TCW; Wang, RJ; Wong, HNC
cis, cis-Cyclohexane-1,3,5-tricarboxylic acid (1) its trimethyl ester (2) and their 1,3,5-trimethylated and 1,3,5-tribenzylated derivatives were prepared, and their structures studied by two-dimensional NMR spectroscopy in conjunction with X-ray crystallography. The results show that these molecules adopt a chair conformation in solution, with all the carboxyl groups in 1 and all the methoxycarbonyl groups in 2 occupying the equatorial positions, but with the corresponding functionalities in the alkylated derivatives occupying the axial positions. For 2, its 1,3,5-tribenzylated derivative 4, and cis, cis-1,3,5-trimethylcyclohexane-1,3,5-tricarboxylic acid (5), the same conformational preferences are seen to persist in the crystalline state as in solution. 1991 Plenum Publishing Corporation.