Parabanic acid derivatives

A parabanic acid derivative of the formula ##STR8## where R.sup.1 denotes alkyl of 1 to 4 carbon atoms, 2-chloroethyl, 2-methoxyethyl, methoxymethyl, allyl, 2-chloropropen-(1)-yl-(3), buten-(1)-yl-(3), propargyl, butyn-(1)-yl-(3), 1-chlorobutyn-(2)-yl-(4), cyclopentyl, cyclohexyl, 3-methylcyclohexyl, 2,6-dimethylcyclohexyl or cyclopropyl and R denotes phenoxyphenyl which is unsubstituted or is substituted in one or both rings by alkyl of 1 to 3 carbon atoms, alkyl of 1 to 3 carbon atoms substituted by 1 to 3 halo atoms, methoxymethyl, cyclohexyl, benzyl, methoxy, ethoxy, methoxy or ethoxy substituted by 1 to 2 halo atoms, from 1 to 3 halo atoms, methylthio, phenyl, thiocyanato, cyano ##STR9## R.sup.2 and R.sup.3 being identical or different and each denoting hydrogen or having the meanings given for R.sup.1.