Reaction Steps
To a stirring solution of tert-butyl D-alaninate (5.60 g, 30.80 mmol) in DMF (50 mL) were added DIEA (8.29 g, 64.18 mmol) and (S)-3-(4-(5-bromopyrimidin-2-yl)phenyl)-2-(5-(tert-butyl)thiophene-2-carboxamido)propanoic acid (12.5 g, 25.67 mmol). The solution was cooled to 0° C. at ice bath and then HATU (9.06 g, 38.50 mmol) in 15 mL DMF solution was slowly added. The reaction was stirred 1 hour at 0° C. and then warmed to RT with stirring for 2 hours. The reaction solution was extracted with DCM (3×50 mL) and aqueous NaHCO3 (3×30 mL). The combined organics were dried over MgSO4 and evaporated. The final compound was purified by column chromatography (40% DCM in hexane) to afford 14.7 g (94%) of tert-butyl ((S)-3-(4-(5-bromopyrimidin-2-yl)phenyl)-2-(5-(tert-butyl)thiophene-2-carboxamido)propanoyl)-D-alaninateas solid powder. LCMS-ESI (m/z) calculated for C29H35BRN4O4S: 614.2. found 615.3 [M+H]+, tR=3.914 min. (Method 16). 1H NMR (400 MHz, CDCl3) δ 8.83 (d, J=3.6 Hz, 2H), 8.36 (d, J=8.2 Hz, 2H), 7.39 (d, J=8.2 Hz, 2H), 7.34 (d, J=3.8 Hz, 1H), 6.81 (d, J=3.8 Hz, 1H), 6.66 (d, J=7.6 Hz, 1H), 6.34 (d, J=7.2 Hz, 1H), 4.88 (d, J=5.9 Hz, 1H), 4.41 (t, J=7.2 Hz, 1H), 3.31 (dd, J=13.6, 5.8 Hz, 1H), 3.20 (dd, J=13.6, 7.8 Hz, 1H), 1.51-1.32 (m, 18H), 1.27 (d, J=7.1 Hz, 3H). 13C NMR (101 MHz, DMSO) δ 172.02, 171.31, 162.28, 162.13, 161.42, 158.55, 142.27, 136.34, 134.66, 130.20, 128.82, 127.92, 123.07, 118.63, 80.90, 54.45, 48.86, 39.59, 39.38, 32.39, 28.04, 17.68.
