Reaction Steps
A solution of pyrazolo[1,5-a]pyrimidine-3-carboxylic acid {3-(5-chloro-2-difluoromethoxy-phenyl)-1-[2-oxo-2-(4-oxo-piperidin-1-yl)-ethyl]-1H-pyrazol-4-yl}-amide.dioxane (36 g, 57.0 mmol) in DCM (500 mL) was treated with 3-amino-propionitrile (5.0 mL, 68.4 mmol) and acetic acid (50 mL). The mixture was cooled in an ice bath before the addition of sodium triacetoxyborohydride (18.1 g, 85.4 mmol) portionwise. The reaction was allowed to warm to room temperature and stirred for 1.5 hours. The mixture was diluted with methanol and loaded onto a pad of Isolute® SCX-2 which had been conditioned with MeOH. After flushing with MeOH, the product was eluted with 2M ammonia in MeOH. The basic fractions were combined and evaporated to afford pyrazolo[1,5-a]pyrimidine-3-carboxylic acid (3-(5-chloro-2-difluoromethoxy-phenyl)-1-{2-[4-(2-cyano-ethylamino)-piperidin-1-yl]-2-oxo-ethyl}-1H-pyrazol-4-yl)-amide as a pale brown solid (31.1 g, 91%). LCMS (Method 3) [M+H]+=598.2, RT=2.25 min. 1H NMR (400 MHz, CDCl3) δ: (ppm) 9.84 (s, 1H), 8.78 (dd, 1H, J=1.6, 6.9 Hz), 8.69 (s, 1H), 8.58-8.55 (m, 1H), 8.40 (s, 1H), 7.68 (d, 1H, J=2.5 Hz), 7.41 (dd, 1H, J=2.7, 8.7 Hz), 7.28 (d, 1H, J=8.7 Hz), 7.28 (s, 1H), 7.00 (dd, 1H, J=4.2, 6.9 Hz), 6.50 (t, 1H, J=74.1 Hz), 5.08 (d, 1H, J=15.4 Hz), 5.02 (d, 1H, J=15.5 Hz), 4.37 (d, 1H, J=13.4 Hz), 3.88 (d, 1H, J=13.4 Hz), 3.22-3.12 (m, 1H), 3.02 (t, 1H, J=6.4 Hz), 2.98-2.86 (m, 2H), 2.82-2.72 (m, 1H), 2.52-2.46 (m, 2H), 1.96-1.83 (m, 2H), 1.36-1.20 (m, 2H).
