METHOD FOR THE PREPARATION OF AMIDINO-UREA DERIVATIVES

The invention relates to an improved method for the preparation of an amidino-urea derivative of general formula (I), wherein R , R and R each stand for hydrogen, halogen, lower alkyl, lower alkoxy, trifluoromethyl, nitro or optionally substituted amino, R is hydrogen or lower alkyl, and R is hydrogen or C1-10 alkyl, by reacting a lower alkyl carbamate with an appropriate guanidine derivative. According to the invention the reaction is performed in the presence of a bipolar aprotic solvent. The invention also relates to a method for preparing an adduct of 1-(2,6-dimethylphenyl)-3-(N-methylamidino)-urea and dimethyl sulphoxide, in which 1-(2,6-dimethylphenyl)-3-(N-methylamidino)-urea, prepared optionally directly in the reaction mixture, is reacted with dimethyl sulphoxide. When decomposing this aduct with water, 1-(2,6-dimethylphenyl)-3-(N-methylamidino)-urea is obtained in extremely pure state.