A mixture of 1.17 g (4.5 mmol) 4-Aminomethyl-4-phenethyl-piperidine-1-carbocylic acid tert-butyl ester (intermediate 3), 1 mg (4.9 mmol) (S)-3-amino-piperidine-1-carboxylic acid tert-butyl ester and 125 μl triethylamin in 50 ml DMF/iso-propanol (1:3) is stirred at 70° C. overnight. Then the reaction mixture is concentrated under reduced pressure. Then 50 ml 25% TFA in dicholoromethane is added and the mixture is stirred for 2 h at room temperature and evaporated. The residue is treated with excess HCl in methanol and evaporated again to yield 430 mg N-(3,5-Diamino-6-chloro-pyrazine-2-carbonyl)-N′-piperidin-3-yl-guanidine. Step B: 100 mg N-(3,5-Diamino-6-chloro-pyrazine-2-carbonyl)-N′-piperidin-3-yl-guanidine, 125 μl triethylamine and 62 mg 3-bromomethyl-benzoic acid methyl ester in 3 ml DMF were stirred at room temperature for 6 h. Then the reaction mixture is concentrated under reduced pressure and the residue is purified by preparative reverse phase HPLC (gradient of acetonitrile and water+0.2% trifluoroacetic acid, 25° C.). Fractions containing the title compound were concentrated under reduced pressure.
