Abstract: Compounds having the formula ##STR1## wherein R and R.sup.1 are hydrogen, halogen, trifluoromethyl or C.sub.1 -C.sub.4 alkoxy and Ar is a substituted phenyl group as herbicide.

Abstract: 1-alkyl-3-arylimidazolidine-2,4-diones are prepared by reacting the herbicidally active intermediate N-phenyl-2-substituted-2-alkylamino acetamides with 1,1'-carbonyldiimidazole in a suitable solvent. These herbicidally active intermediates are prepared by reacting alpha-haloacetanilides with the primary amine of choice in an alcohol solvent, in the presence or absence of water, at ambient temperature.

Abstract: 5-Substituted 2,4-imidazolidinediones having the formula ##STR1## wherein R is alkyl, phenyl or phenyl substituterd with alkyl, alkoxy, halo, haloalkyl, nitro or combinations thereof;R.sub.1 is alkyl, cycloalkyl, carboalkyl, alkylcarboalkyl, carboalkoxy, thionocarboalkoxy, phenyl, phenalkyl, phenyl substituted with alkyl, alkoxy, haloalkyl, nitro or combinations thereof; benzyl or benzyl substituted with one or more halo; pyridine, pyridine substituted with halo; or heterocycle such as, but not limited to, pyrimidine, pyrimidine substituted with halo, alkyl or combinations thereof; imidazole, methylimidazole; benzimidazole; triazole, triazole substituted with haloalkyl, alkyl or combinations thereof; triazoline, triazoline, triazoline substituted with haloalkyl, alkyl, or combinations thereof; thiazole or thiazole substituted with phenyl;R.sub.