To a solution of (S)-2-[4-(2-chloro-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 (1.00 g, 1.99 mmol) in 2-propanol (4 mL) was added 2N hydrochloric acid (4.00 mL, 8.00 mmol). The mixture was stirred for 2 h at 25° C. Water (4 mL) was added and the mixture was thoroughly extracted with methyl t-butyl ether (30 mL). The organic layer was separated and washed with 1N sodium hydroxide (20 mL) and then brine (20 mL). Concentration of the organic layer provided a white foam. The foam was chopped up with a spatula to afford (S)-2-[4-(2-chloro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-4-methyl-pentanoic acid [1-((R)-2,3-dihydroxy-propyl)-1H-pyrazol-3-yl]-amide (890 mg, 96.7%) as an off-white solid: LR-ES-MS m/z calculated for C22H27ClN4O5 [M]+ 462, [M+H]+ observed 463.
