47 mg of (S)-2-amino-3-cyclohexyl-propan-1-ol and 0.14 ml DIPEA were dissolved in 2 ml dry THF. The mixture was cooled to −10° C. and 67 mg of 2-cyclopentylmethyl-1-(1-ethyl-propyl)-1H-benzoimidazole-5-carbonyl chloride in 1 ml of dry THF were added. The mixture was stirred under exclusion of moisture for 15 min at −10° C. and then at RT over night. It was then filtered, the filter was washed with 10 ml ethyl acetate. The filtrate was evaporated, the residue was taken up in 20 ml ethyl acetate and extracted with 20 ml 5% NaHCO3. The organic phase was dried and evaporated and the residue was purified by HPLC to yield 24 mg (27%) of 2-cyclopentylmethyl-1-(1-ethyl-propyl)-1H-benzoimidazole-5-carboxylic acid ((S)-1-cyclohexylmethyl-2-hydroxy-ethyl)-amide.
