Dimethylformamide → 2-(2-tert-butoxycarbonylamino-ethyl)-4-(4-fluoro-phenyl)-5-formyl-1H-pyrrole-3-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A stirred solution of dichloromethane (5 ml) and N,N-dimethylformamide (0.6 ml) was added dropwise slowly with phosphorus oxychloride (0.414 ml, 4.5 mmol) under an argon atmosphere while maintaining the temperature at −0° C.˜0° C. Upon completion of the addition, the mixture was stirred for 15 minutes at −1° C., added with the solution of 2-(2-tert-butoxycarbonylamino-ethyl)-4-(4-fluoro-phenyl)-1H-pyrrole-3-carboxylic acid ethyl ester (1.125 g, 3 mmol) in dichloromethane (3 ml) while maintaining the temperature at −10° C.˜0° C. for 1 hour. The mixture was stirred for another 2.5 hours at room temperature, added with cold water, adjusted to pH 11˜12 with 10% aqueous sodium hydroxide solution, extracted with ethyl acetate (50 ml×6), washed with brine, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 2-(2-tert-butoxycarbonylamino-ethyl)-4-(4-fluoro-phenyl)-5-formyl-1H-pyrrole-3-carboxylic acid ethyl ester (1.02 g, 84.37%) as a red oil.

Provenance & Evidence