350 mg of benzyl [1-(5-amino-[1,3,4]oxadiazol-2-yl)-3-phenylpropyl]-carbamate were dissolved in 5 ml of dry dimethyl sulfoxide, treated with 140 mg of potassium carbonate and 140 mg of methyl isocyanate, and stirred at 80° C. for 16 h. The reaction mixture was cooled, treated with ethyl acetate, washed twice with water and once with saturated sodium chloride solution, dried over magnesium sulfate, filtered, and concentrated in vacuo. Benzyl {1-[5-(3-methylureido)-[1,3,4]oxadiazol-2-yl]-3-phenylpropyl}carbamate was obtained, which was employed in the next stage (hydrogenolysis) without further purification.
