Reaction Steps
5-(4-azidophenyl)-2-tert-butoxycarbonylaminoimidazole-1-carboxylic acid tert-butyl ester (0.080 g, 0.200 mmol), 1-ethynyl-3,5-difluorobenzene (0.035 g, 0.26 mmol), CuSO4.5H2O (0.097 g, 0.040 mmol), and sodium ascorbate (0.004 g, 0.020 mmol) were all charged in a reaction vessel and dissolved in a 1:1:1 mixture of H2O (0.75 mL), EtOH 0.75 mL), and CH2Cl2 (0.75 mL). The reaction was stirred at ambient temperature for 16 h. After the reaction was quenched with sat. NaHCO3 and diluted with EtOAc (50 mL). The organic layer was washed with sat. NaHCO3 (3×20 mL) before being dried (Na2SO4), filtered and evaporated to dryness. The crude product was purified by column chromatography (10%-30% EtOAc/Hexanes) to afford 0.068 g (44%) of 2-tert-butoxycarbonylamino-5-{4-[4-(4-pentylphenyl)-[1,2,3]triazol-1-yl]phenyl}imidazole-1-carboxylic acid tert-butyl ester as a white solid: 1H NMR (300 MHz, DMSO-d6) δ 9.60 (s, 1H), 9.29 (s, 1H), 8.01 (m, 3H), 7.98 (d, 2H, J=6.0 Hz), 7.85 (d, 2H, J=5.6 Hz), 7.32 (d, 2H, J=5.4 Hz), 2.62 (t, 2H, J=5.1 Hz), 1.59 (s, 9H), 1.47 (m, 2H), 1.45 (s, 9H), 1.30 (m, 4H), 0.87 (m, 3H); 13C NMR (75 MHz, DMSO-d6) δ 152.8, 147.2, 142.3, 139.9, 135.5, 128.9, 127.8, 127.6, 125.9, 120.1, 118.9, 113.5, 85.5, 80.0, 38.7, 31.3, 30.8, 27.9, 27.3, 21.9, 13.9; HRMS (ESI) calcd for C32H40N6O4 (M+) 572.3111. found 572.3113.
