| abstract |
Process for the preparation of pure asymmetrically disubstituted ureas of the general formula <IMAGE> in which R is an unsubstituted or mono- or polysubstituted by halogen atoms, alkyl, alkoxy, aryloxy or trifluoromethyl groups, an unsubstituted or mono- or polysubstituted by halogen atoms, alkyl -, Alkoxy or trifluoromethyl groups substituted oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, benzoxazolyl or benzthiazolyl radical and R1 and R2 independently of one another represent a hydrogen atom or an alkyl group, where R1 and R2 are not simultaneously hydrogen, or R1 and R2 together mean a butylene or pentylene group, by reacting an N-alkyl or N, N-dialkylurea with an optionally substituted arylamine or a heterocyclic amine in the presence of that amine which is present in the starting product, the respective N-alkyl or N, N-dialkylurea , is already included. |