N-[(1S,2R)-2-({[(1R)-1-Cyano-2-hydroxyethyl]amino}carbonyl)cyclohexyl]-1-methyl-1H-indole-2-carboxamide from Example 4 (0.20 g, 0.54 mmol) was dissolved in dichloromethane (8 mL), cooled to 0° C. under nitrogen in the dark, and stirred for 15 minutes. Trimethyloxonium tetrafluoroborate (0.10 g, 0.68 mmol) was added (Sowinski, J. A.; Toogood, P. L. J. Org. Chem. 1996, 61, 7671). After 20 minutes, proton sponge (0.14 g, 0.65 mmol) was added, and the reaction was allowed to warm to room temperature and was stirred for 21 hours. The reaction mixture was filtered through a pad of celite and the pad washed with dichloromethane. The filtrate was washed with 1M hydrochloric acid, brine, dried on magnesium sulfate, and concentrated. Purification by column chromatography (5:95 methanol:dichlormethane) gave 1-methyl-1H-indole-2-carboxylic acid {(1S,2R)-2-[((R)-cyano-methoxymethyl-methyl)-carbamoyl]-cyclohexyl}-amide (0.08 g, 38%). MS: 383 (M+H).
