[1-(Tert-butoxycarbonylamino-methyl)-cyclohexyl]-acetic acid (271 mg, 1 mmol) was dissolved in dry dichloromethane (5 ml) and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC-HCl; 576 mg, 3 mmol, 3 molequivalents) and triethylamine (404 mg, 4 mmol, 4 molequivalents) were added thereto. After 10 minutes of stirring, diethylamine (146 mg, 2 mmol, 2 molequivalents) and 4-dimethylamino-pyridine (DMAP; 25 mg, 0.2 mmol, 0.2 molequivalents) were added to the reaction mixture, and the mixture was stirred at 25° C. for 20 hours, while monitoring the reaction by TLC using a 2:8 hexane:ethyl acetate mixture as eluent, and until the appearance of a spot of the amide in the middle of the TLC plate was observed. Chloroform was thereafter added and the mixture was washed with NaHCO3, twice with 1M HCl, dried over Na2SO4 and the solvents were evaporated under reduced pressure to give (1-diethylcarbamoylmethyl-cyclohexylmethyl)-carbamic acid tert-butyl ester (248 mg, 76% yield) as a yellow oil.
