Reaction Steps
To a 0° C. solution of 4-{3-[N,N-bis-(tert-butoxycarbonyl)aminomethyl]-phenyl}-piperidine (0.1545 g, 0.3956 mmol, EXAMPLE 1B), 5-tert-butoxycarbonylamino-nicotinic acid (0.0966 g, 0.4055 mmol), 1-hydroxy-7-azabenzotriazole (0.0290 g, 0.2131 mmol), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.1500 g, 0.7824 mmol) in dimethylformamide (5.0 mL) was added pyridine (0.065 mL, 0.8037 mmol). The reaction mixture was stirred 30 minutes at 0° C., then allowed to warm to room temperature under inert atmosphere. After 16 hours at ambient temperature the reaction solution was diluted with ethyl acetate (30 mL), washed with saturated ammonium chloride (2×15 mL), saturated sodium bicarbonate (15 mL), and brine (15 mL). The organic phase was dried over magnesium sulfate, filtered, and evaporated to dryness. The residue was purified by silica gel chromatography eluting with a mixture of ethyl acetate and methylene chloride (1:1, v/v) to give {5-[1-(4-{3-[N,N-bis-(tert-butoxycarbonyl)aminomethyl]-phenyl}-piperidin-1-yl)methanoyl]-pyridin-3-yl}carbamic acid tert-butyl ester as a colorless oil (0.1812 g): TLC, 50:50-methylene chloride:ethyl acetate, Rf=0.20. 1H NMR (300 MHz, CDCl3) δ 8.67 (d, J=2.6 Hz, 1H), 8.34 (d, J=1.4 Hz, 1H), 8.09 (s, 1H), 7.93 (s, 1H), 7.21-7.35 (m, 1H), 7.08-7.18 (m, 3H), 4.81-4.93 (m, 1H), 4.78 (s, 2H), 3.81-3.93 (br m, 1H), 3.11-3.28 (br m, 1H), 2.70-2.96 (m, 2H), 1.51 (s, 9H), 1.45 (s, 18H), 1.40-2.02 (m partially obscured, 4H); 13C NMR (75 MHz, CDCl3) δ 167.5, 152.6, 152.5, 144.8, 141.3, 141.0, 138.9, 135.7, 131.8, 128.5, 125.6, 125.3, 125.2, 124.1, 82.4, 81.0, 77.2, 49.3, 42.5, 28.1, 27.8; MS (CI) m/z 611 (M+H).
