[Br:1][C:2]1[NH:6][N:5]=[C:4]([CH:7]2[CH2:12][CH2:11][N:10]([C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])[CH2:9][CH2:8]2)[N:3]=1.[N+](=[CH:22][Si](C)(C)C)=[N-].CCCCCC>C1(C)C=CC=CC=1.CO>[Br:1][C:2]1[N:6]([CH3:22])[N:5]=[C:4]([CH:7]2[CH2:12][CH2:11][N:10]([C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])[CH2:9][CH2:8]2)[N:3]=1
To a stirred suspension of tert-butyl 4-(5-bromo-1H-1,2,4-triazol-3-yl)piperidine-1-carboxylate (26 g, 78.50 mmol) in toluene (200 mL) and methanol (50 mL) was added dropwise (diazomethyl)trimethylsilane 2M solution in hexane (43.2 mL, 86.35 mmol) under N2, keeping temperature around 20° C.: gas evolution and a small exotherm were observed. The yellow solution obtained was stirred at room temperature for 1 h. The solvent were evaporated and the resulting oil was purified on silica, eluting with 40% EtOAc in petroleum ether to afford tert-butyl 4-(5-bromo-1-methyl-1H-1,2,4-triazol-3-yl)piperidine-1-carboxylate (15.00 g, 55.3%) as an oil: 1H NMR Spectrum; (CDCl3) 1.46 (9H, s), 1.65-1.78 (2H, m), 1.90-2.01 (2H, m), 2.68-3.02 (3H, m), 3.83 (3H, s), 3.94-4.31 (2H, m); Mass Spectrum [M+H]+=no mass ion.
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