Cesium carbonate → tert-butyl (5-(2-(3-methyl-1H-1,2,4-triazol-1-yl)-5-nitrophenoxy)pentan-2-yl)carbamate

Participants

Reaction Steps

To a stirred solution of 2-(3-methyl-1H-1,2,4-triazol-1-yl)-5-nitrophenol (1.1 g, 5.00 mmol), cesium carbonate (2.44 g, 7.49 mmol) in DMF (20 mL) was added tert-butyl (5-bromopentan-2-yl)carbamate (2.45 g, 9.25 mmol) at room temperature. The reaction mixture was stirred at rt for 18 h while monitoring by TLC and LC-MS. The solvent was removed under reduced pressure and the residue was dissolved in ethyl acetate (250 mL) and washed with brine (2×100 mL). The organic layer was concentrated under reduced pressure and was purified by flash chromatography using a Teledyne ISCO instrument (40 g silica column, 2-3% of methanol in chloroform) to give tert-butyl (5-(2-(3-methyl-1H-1,2,4-triazol-1-yl)-5-nitrophenoxy)pentan-2-yl)carbamate (1.5 g, 74.1%) as a light brown solid. LC-MS (M+H)+=406.2. 1H NMR: (400 MHz, CDCl3) δ ppm 8.86 (1H, s), 8.09-8.07 (1H, d, J=8.8 Hz), 7.99-7.93 (2H, m), 4.33 (1H, br s), 4.27-4.24 (2H, t, J=6.4 Hz), 3.73 (1H, br s), 2.50 (3H, s), 1.98-1.95 (2H, m), 1.61-1.57 (2H, m), 1.44 (9H, s), 1.17-1.15 (3H, d, J=8 Hz).

Provenance & Evidence