[NH:1]1[CH:5]=[CH:4][CH:3]=[N:2]1.[H-].[Na+].[C:8]([O:12][C:13]([NH:15][C@H:16]([CH3:23])[CH2:17]OS(C)(=O)=O)=[O:14])([CH3:11])([CH3:10])[CH3:9].O>CN(C=O)C.C(OCC)(=O)C>[C:8]([O:12][C:13](=[O:14])[NH:15][C@H:16]([CH3:17])[CH2:23][N:1]1[CH:5]=[CH:4][CH:3]=[N:2]1)([CH3:11])([CH3:10])[CH3:9]1H-Pyrazole (70 mg, 1.03 mmol) was dissolved in DMF (5 ml) and cooled in an ice bath. Sodium hydride (60% dispersion in mineral oil, 41 mg, 1.03 mmol) was added and the reaction was stirred for 15 min. Methanesulfonic acid (R)-2-tert-butoxycarbonylamino-propyl ester (200 mg, 0.79 mmol) was then added and the mixture was stirred at 50° C. for 16 h. The reaction was cooled to room temperature and water and ethyl acetate were added. The aqueous layer was extracted twice more with ethyl acetate and the combined organic layers were washed with sodium chloride solution and dried over sodium sulfate. After evaporation, the residue was purified by silica gel chromatography (methanol/dichloromethane) to give 129 mg (72%) of ((R)-1-methyl-2-pyrazol-1-yl-ethyl)-carbamic acid tert-butyl ester. (M+H)+=226.
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