Structure elucidation of two diphenylhydantoin derivatives via 1H and 13C NMR spectroscopy

The solution conformations of 1-benzyl-5,5-diphenyl-2,4-dioxo-3-imidazolidineacetic acid (AC) and 3-(2,4-dichlorobenzyl)-5,5-diphenyl-2,4-dioxo-1-imidazolidine acetic acid (AD) were studied by proton and carbon NMR spectroscopy. The two drugs have different pharmacological activities, AC having anticonvulsant and AD having antidepressant but no anticonvulsant properties. The relative orientations of the hydantoin ring substituents were investigated and are discussed in terms of amphipathic distribution of polar and apolar domains.