To a solution of 3-methyl-N2-phenyl-benzene-1,2-diamine (852 mg, 4.3 mmol) in anhydrous DCM (20 mL) were added (S)-2-benzyloxycarbonylaminopropionic acid (1.44 g, 6.45 mmol), HOBt (639 mg, 4.73 mmol), 4-methylmorpholine (1.04 mL, 9.46 mmol) and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (1.24 g, 6.45 mmol). The mixture was stirred at RT for 6.5 h and then partitioned between DCM (100 mL) and water. The organic layer was then washed with brine, dried (Na2SO4) and concentrated in vacuo. The resulting residue was dissolved in AcOH (10 mL) and heated to 65° C. for 18 h. After cooling to RT, volatiles were removed under reduced pressure and the residue diluted with EtOAc (100 mL). The organic layer was washed with a saturated solution of NaHCO3, followed by brine, then dried (Na2SO4) and concentrated in vacuo affording [(S)-1-(7-Methyl-1-phenyl-1H-benzoimidazol-2-yl)ethyl]carbamic acid benzyl ester as brown foam (1.5 g, 90%). LCMS: RT 3.07 min [M+H]+ 386.2.
