Methyl 3-amino-6-bromo-2-(4-(morpholine-4-carbonyl)phenyl)isonicotinate (2.00 gm, 4.76 mmol) was dissolved in trifluoroacetic acid (26 mL) and the yellow solution was cooled in an ice-bath. Powdered sodium nitrite (0.657 gm, 9.52 mmol) was added with stirring to give a dark red mixture. After 30 minutes, powdered sodium azide (3.09 gm, 47.6 mmol) was added followed by diethyl ether (26 mL). The light red mixture was stirred in the ice-bath for 30 minutes. The reaction was partitioned between EtOAc and sufficient saturated aqueous NaHCO3 solution (gas evolution) to neutralize the acid. The organic phase was washed with brine, dried over sodium sulfate, and concentrated to about 50 mL on the rotary evaporator. The resulting solid was collected by filtration and washed three times with EtOAc to give methyl 3-azido-6-bromo-2-(4-(morpholine-4-carbonyl)phenyl)isonicotinate (5.86 gm, 72% yield). Removal of the solvent from the filtrate followed by flash silica gel chromatography (step gradient elution with methylene chloride containing 0 to 2% MeOH) afforded another 1.58 gm of product. MS (ESI) m/z 446 and 448 (M+H). 1H NMR (CDCl3) δ ppm 7.82-7.80 (3H, m), 7.49-7.53 (2H, m), 4.02 (3H, s), 3.69-3.88 (4H, m), 3.57-3.70 (2H, m), 3.40-3.53 (2H, m).
