Reaction Steps
EDC (2.0 equiv.) and HOAt (2.0 equiv.) were added to a solution of (+/−)-tert-butyl (1R,2S,3S,5R)-5-(3-aminopyridin-4-yl)-3-methyl-2-(2-(methylsulfonyl)ethoxy)cyclohexylcarbamate (1.0 equiv.) and 6-(2,6-difluorophenyl)-5-fluoropicolinic acid (1.5 equiv.) in DMF (0.08 M). The mixture was stirred at ambient temperature overnight. The reaction mixture was diluted with water and extracted with ethyl acetate. The combined extracts were washed sequentially with 1M aqueous sodium hydroxide and brine, dried over sodium sulfate, filtered, concentrated and purified by ISCO SiO2 chromatography. Purification was completed via SFC (50% MeOH, 100 mL/min, IC column) to yield tert-butyl (1S,2R,3R,5S)-5-(3-(6-(2,6-difluorophenyl)-5-fluoropicolinamido)pyridin-4-yl)-3-methyl-2-(2-(methylsulfonyl)ethoxy)cyclohexylcarbamate (48% yield, 99% ee) and tert-butyl (1R,2S,3S,5R)-5-(3-(6-(2,6-difluorophenyl)-5-fluoropicolinamido)pyridin-4-yl)-3-methyl-2-(2-(methylsulfonyl) ethoxy)cyclohexylcarbamate (48% yield, 99% ee). LC/MS (m/z)=663.2 (MH+), Rt=0.88 min. 1H NMR (400 MHz, <cdcl3>) δ ppm 0.95 (d, J=6.75 Hz, 3 H), 1.45 (s, 8 H), 1.50-1.84 (m, 5 H), 2.80-2.95 (m, 1 H), 3.08 (s, 3 H), 3.14-3.29 (m, 1 H), 3.32-3.45 (m, 1 H), 3.56 (br. s., 1 H), 3.63-3.77 (m, 1 H), 3.95-4.08 (m, 1 H), 4.12 (q, J=7.12 Hz, 1 H), 5.36 (d, J=8.56 Hz, 1 H), 7.04-7.18 (m, 3 H), 7.50 (tt, J=8.47, 6.35 Hz, 1 H), 7.77 (t, J=8.56 Hz, 1 H), 8.33-8.46 (m, 2 H), 9.26 (s, 1 H), 9.81 (s, 1 H).
