Acetohydroxamic acid (54 mg, 0.72 mmol) and K2CO3 (0.2 g, 1.45 mmol) were added to 8 mL of DMF and 4 mL of H2O. The mixture was stirred at rt for 15 min, followed by addition of a solution of 2-fluoro-5-[7-oxo-6-[4-(2-oxo-1-piperidinyl)phenyl]-3-(trifluoromethyl)-4,5,6,7,-tetrahydro-1H-pyrazolo[3,4-c]pyridin-1-yl]benzonitrile (0.12 g, 0.24 mmol) in DMF (2 mL). The mixture was stirred at rt overnight. The mixture was then partitioned between ethylacetate (40 mL) and water (20 mL), washed with H2O (20 mL×3) and brine (20 mL), dried over Na2SO4, filtered, and concentrated. HPLC(C18 RP., 0.5% TFA, H2O/MeCN gradient) purification gave 100 mg (67% yield) of the title compound as its TFA salt. LRMS (ESI−): 623.4 (M+TFA-H)−. 1H NMR (CDCl3) δ 7.80 (s, 1H), 7.72 (d, 1H), 7.44 (d, 1H), 7.34-7.24 (m, 4H), 4.16 (t, 2H), 3.98 (br, 2H), 3.61 (br, 2H), 3.20 (t, 2H), 2.60 (br, 2H), 1.98-1.89 (m, 4H).
