Reaction Steps
A solution of (S)-2-[4-(2,5-difluoro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-4-methyl-pentanoic acid [1-((R)-2,2-dimethyl-[1,3]dioxolan-4-yl-methyl)-1H-pyrazol-3-yl]-amide (0.35 g, 0.70 mmol) in methanol (7.1 mL) at 25° C. was treated with p-toluenesulfonic acid monohydrate (20 mg, 0.10 mmol). The reaction was stirred at 25° C. overnight. At this time, the reaction was diluted with ethyl acetate (000 mL) and was washed with a saturated aqueous sodium bicarbonate solution (1×150 mL) and a saturated aqueous sodium chloride solution (1×150 mL), dried over sodium sulfate, filtered and concentrated in vacuo. Purification by Analogix flash chromatography (40 g, 2-5% methanol/dichloromethane) afforded (S)-2-[4-(2,5-difluoro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-4-methyl-pentanoic acid [1-((R)-2,3-dihydroxy-propyl)-1H-pyrazol-3-yl]-amide (0.23 g, 71%) as a pale orange solid: HR-ES-MS m/z calculated for C22H26N4O5F2 [M+H]+ 465.1944, observed 465.1943; 1H NMR (300 MHz, DMSO-d6) δ ppm 0.88 (d, J=6.3 Hz, 3H), 0.92 (d, J=6.3 Hz, 3H), 1.43 (br. s., 1H), 1.48-1.63 (m, 1H), 1.66-1.82 (m, 1H), 3.18-3.31 (m, 2H), 3.66-3.79 (m, 1H), 3.84 (dd, J=13.4, 7.5 Hz, 1H), 4.07 (dd, J=13.4, 3.6 Hz, 1H), 4.20 (d, J=18.4 Hz, 1H), 4.58 (d, J=18.4 Hz, 1H), 4.69 (t, J=5.6 Hz, 1H), 4.86 (dd, J=10.7, 4.7 Hz, 1H), 4.92 (d, J=5.4 Hz, 1H), 5.01 (s, 1H), 6.39 (d, J=2.1 Hz, 1H), 7.15-7.32 (m, 1H), 7.43-7.60 (m, 3H), 10.76 (s, 1H).
