Localization of substituents in the hydantoin ring by nuclear magnetic resonance

Abstract

Taking into account the chemical shifts of protons at positions 1, 3 and 5, the characteristic changes of the N 1H and N 3H signals on addition of bases and the absorption area of the C 5H region, all the unsubstituted sites of the ring in hydantoin compounds can be easily determined; comparison of the behavior towards bases in deuteriochloroform and dimethyl sulfoxide is helpful (Table 1). The localization of methyl substituents at ring positions 1, 3 and 5 is ascertained by considering the chemical shifts (Table 2).