Diisopropylethylamine → {1-[2-(4-Bromo-phenyl)-2-oxo-ethylcarbamoyl]-cyclopropyl}-carbamic acid tert-butyl ester

Participants

Reaction Steps

2-Amino-1-(4-bromo-phenyl)-ethanone HCl (2.5 g, 10 mmol) in DMF (30 mL) was treated with 1-tert-butoxycarbonylamino-cyclopropanecarboxylic acid (1.97 g, 9.8 mmol), HATU (4.02 g, 10.5 mmol), and DIPEA (5.6 mL, 31.1 mmol). The mixture was stirred for 18 hours and concentrated. The mixture was diluted with EtOAc (25 mL), and washed with saturated NaHCO3 (310 mL), H2O (10 mL), and brine (10 mL). The solution was dried over MgSO4 and subjected to a 80 g SiO2 COMBIFLASH column (0-100% EtOAc-hexanes gradient) to afford {1-[2-(4-bromo-phenyl)-2-oxo-ethylcarbamoyl]-cyclopropyl}-carbamic acid tert-butyl ester (3.49 g, 90%). This material (3.49 g, 8.8 mmol) in xylenes (20 mL) was treated with ammonium acetate (3.4 g, 44 mmol). The reaction was stirred at 130° C. in a sealed tube for 18 hours. The mixture was concentrated and suspended in dicholormethane (100 mL) and washed with saturated NaHCO3 (50 mL). The solution was dried over MgSO4 to afford crude {1-[5-(4-bromo-phenyl)-1H-imidazol-2-yl]-cyclopropyl}-carbamic acid tert-butyl ester, which was used without further purification: MS (ESI) m/z 379 [M+H]+.

Provenance & Evidence