A solution of diethyl malonate (1.21 mL, 7.97 mmol) in DMF (2 mL) was added dropwise to a suspention of NaH (348 mg, 7.97 mmol, 55% in mineral oil) in DMF (5 mL) at 0 ° C. under argon. The reaction mixture was stirred for 45 min and a solution of (5-bromomethyl-6-methyl-pyridin-2-yl)-carbamic acid tert-butyl ester (2.0 g, 6.64 mmol) in DMF (5 mL) was added dropwise. The mixture was stirred over night (0° C.→20° C.). EtOAc was added and the solution was washed with water and brine, dried and concentrated under reduced pressure. Flash chromatography (heptane/EtOAc, 4:1) gave 2-(6tert-butoxycarbonylamino-2-methyl-pyridin-3-ylmethyl)-malonic acid diethyl ester (1.87 g, 74%).
