B series of a-hydroxyamides of the type I and the derived oxazolidinediones of the type I1 have been examined for central nervous system depressant effects. Many compounds showed significant activity. A new and convenient prwess for synthesis of oxazolidinediones of the type I1 in one step from the a-hydroxyester, the dialkylaminoalkylamine and diethyl carbonate is described.