Synthesis of imidazolidinediones and oxazolidinediones from cyclization of propargylureas and propargyl carbamates

Abstract
A synthetic procedure for the preparation of imidazolidinediones by the base-catalyzed cyclization of propargylureas is described. The method may be the most versatile way of obtaining these compounds containing tertiary groups substituted on ring-N number 3. Of the derivatives, 3-tert-butyl-5,5-dimethyl-2,4-imidazolidinedione showed a moderate level of subcutaneous metrazole seizure threshold activity (scMet indicates potential for control of petit mal epileptic seizures) in control screens on mice as determined by the National Institute of Neurological and Communicative Disorders and Stroke.