MOLECULAR-DYNAMICS OF HYDANTOINS AND BARBITURATES ASSESSED BY H-1,C-13 AND N-15 RELAXATION DATA

The molecular dynamics of hydantoin, 5,5-dimethylhydantoin, 5,5-diphen ylhydantoin, barbituric acid and 5-ethyl-5-phenylbarbituric acid in so lution are determined to investigate the molecular basis for the activ ity of these neuroactive drugs. From dipolar C-13 and N-15 spin-lattic e relaxation times the correlation times for the rotational dynamics o f specific bond vectors are evaluated. Conclusions can be drawn concer ning the anisotropy of the overall molecular rotational motion and the internal rotations of molecular segments. The translational molecular diffusion coefficients are obtained from self-diffusion measurements by the pulsed gradients method. The observed differences in the dynami cs as well as structural differences may account for the variation in the neuroactivity of the studied compounds.