Benclonidine has been synthesized by various routes: 1) Condensation of 1-benzoylimidazolidin-2-one (II) [obtained by reaction of imidazolidin-2-one (I) with benzoyl chloride (A)] and 2,6-dichloroaniline (III) in the presence of phosphoroxy chloride at elevated temperature yields title compound. (1) 2) Clonidine (IV) reacts with benzoylimidazole (V) in aprotic solvents to give directly benclonidine. (2) 3) 2,6-Dichlorophenylisocyanide dichloride (VI) and benzoylethylenediamine (VII) are condensed in the presence of an acid acceptor to give benclonidine. (2)