To a 25 mL round-bottomed flask equipped with a magnetic stir bar was added 2′,4′-difluoro-3-hydroxybiphenyl-4-carboxylic acid (0.301, 1.20 mmol), N,N-Dimethylformamide (5 mL), N,N′-Dicyclohexylcarbodiimide (0.248 g, 1.20 mmol) and n-methylmorpholine (0.25 mL). The reaction mixture was cooled to 0° C. and allowed to stir. Then, 2-azidoethanamine (0.1037 g, 1.20 mmol) was added dropwise and allowed to slowly warm to room temperature while stirring for 24 hr. The reaction mixture was diluted with water, extracted with dichloromethane, washed with 1N HCl, washed with saturated sodium bicarbonate, washed with brine and then concentrated de vacuo. The resulting residue was then purified via silica gel column chromatography (1:40 methanol:dichloromethane to 1:10 methanol:dichloromethane) to give N-(2-azidoethyl)-2′,4′-difluoro-3-hydroxybiphenyl-4-carboxamide (0.232 g, 61% yield). 1H NMR (300 MHz, CDCl3) δ 7.60 (s, 1H), δ 7.47 (d, 1H), δ 7.29 (m, 2H), δ 7.02 (d, 1H), δ 6.88 (m, 2H) ppm; 13C NMR (75 MHz, CDCl3) δ 170.3, 160.8, 135.1, 131.3, 131.2, 131.3, 131.2, 126.8, 118.8, 114.6, 112.0, 111.8, 104.8, 104.6, 104.3, 50.7, 39.3 ppm; HRMS (ESI) calcd for C1-15H12F2N4O3 (M+) 318.0928, found 318.0933.
