[Cl:1][C:2]1[N:7]=[C:6]([NH:8][CH:9]2[CH2:14][CH2:13][N:12]([C:15]([O:17][C:18]([CH3:21])([CH3:20])[CH3:19])=[O:16])[CH2:11][CH2:10]2)[CH:5]=[N:4][CH:3]=1.CI.[CH3:24][Si]([N-][Si](C)(C)C)(C)C.[Na+]>C1COCC1>[Cl:1][C:2]1[N:7]=[C:6]([N:8]([CH3:24])[CH:9]2[CH2:14][CH2:13][N:12]([C:15]([O:17][C:18]([CH3:21])([CH3:20])[CH3:19])=[O:16])[CH2:11][CH2:10]2)[CH:5]=[N:4][CH:3]=1To a stirred solution of tert-butyl 4-[(6-chloropyrazin-2-yl)amino]piperidine-1-carboxylate (0.165 g, 0.528 mmol) in THF (2.6 ml) was added methyl iodide (0.165 ml, 2.64 mmol). The solution was cooled to 0° C., and a solution of NaHMDS in THF (1M; 1.06 ml, 1.06 mmol) was added. The reaction mixture was allowed to warm to room temperature and stirred for 2 h. The reaction was quenched with saturated aqueous ammonium chloride (50 mL, and extracted with EtOAc (2×50 mL). The combined EtOAc layers were washed with brine (50 mL), dried over magnesium sulfate, filtered and concentrated. The crude residue was purified by silica gel chromatography (EtOAc/Hexanes gradient) to afford tert-butyl 4-[(6-chloropyrazin-2-yl)(methyl)amino]piperidine-1-carboxylate as a yellow oil. LRMS calculated for C15H23ClN4O2 [M+Na]+, 349.2; found 349.0.
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