Cycloaddition of thioglycolic acid to 3a-3h, yielded 5-[(2'-substituted phenyl-4'-oxothiazolidin-3'-yl)amino]-2-oxo/thiobarbituric acids (4a-4h). All these compounds were screened, in vivo, for their anticonvulsant activity and acute toxicity studies. Compounds 4f and 4g were found to be most potent compounds of this series and were compared with the reference drugs, phenytoin sodium, lamotrigine and sodium