trans-(4-Hydroxymethyl-cyclohexyl)-carbamic acid tert-butyl ester (480 mg, 2.46 mmol, 1.0 eq) is added at room temperature to a stirred solution of 6-methoxy-quinoline-3-carboxylic acid (564 mg, 2.46 mmol, 1.0 eq) in dichloromethane (15 mL), followed by 1-hydroxybenzotriazole (532 mg, 3.94 mmol, 1.6 eq), N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (1.04 g, 5.41 mmol, 2.2 eq) and triethylamine (754 μL, 5.41 mmol, 2.2 eq). After 15 hours stirring at 30° C., solvent is evaporated and the residue is purified by column chromatography (silica gel, eluent: petroleum ether:ethyl acetate, 4:1, v/v) to afford 6-methoxy-quinoline-3-carboxylic acid trans-4-tert-butoxycarbonylamino-cyclohexylmethyl ester as a white powder (787 mg, 77% yield).
