Triethylamine → (2-Pyridin-3-yl-4-trifluoromethyl-thiazol-5-yl)-carbamic acid tert-butyl ester

Participants

Reaction Steps

To 2-pyridin-3-yl-4-trifluoromethyl-thiazole-5-carboxylic acid (6.33 g, 23.1 mmol) in toluene/tert-butyl alcohol (100 mL each) was added Et3N (3.21 mL, 23.1 mmol) and diphenyl phosphoryl azide (5 mL, 23.1 mmol). The reaction mixture was stirred at room temperature for 5 min and then heated at 95° C. for 4 h. The mixture was cooled to room temperature and the solvents were removed under reduced pressure. The crude product was purified by silica gel column chromatography (0 to 100% ethyl acetate/hexanes) to give the desired product as a white solid (4.7 g, 59%): mp 145-147° C.; 1H NMR (300 MHz, CDCl3) δ 9.11 (dd, J=2.5, 0.8 Hz, 1H), 8.67 (dd, J=5.0, 1.7 Hz, 1H), 8.22 (ddd, J=8.0, 2.5, 1.7 Hz, 1H), 7.58 (br s, 1H), 7.39 (ddd, J=8.0, 4.7, 0.8 Hz, 1H), 1.59 (s, 9H); ESIMS m/z 346.5 (M+1), m/z 344.2 (M−1).

Provenance & Evidence