5, 5-Disubstituted barbituric acid derivatives, such as phenobarbital (1a), generally exhibit CNS depressant activ-ity (1). However, slight structural modifications in many de-pressant barbiturates produce compounds with excitatory or convulsant activity, eg, 5-benzyl-5- ethylbarbituric acid (1b)(1—3) a homologue of phenobarbital. The structure and conformation of the C-5 side chains of the barbiturates have been suggested to be ...
