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

Participants

Reaction Conditions

Reaction Steps

A stirred solution of dichloromethane (5.5 ml) and N,N-dimethylformamide (0.2 ml) was added dropwise slowly with phosphorus oxychloride (0.184 ml, 2 mmol) under an argon atmosphere while maintaining the temperature at −10° C.˜0° C. Upon completion of the addition, the mixture was stirred for 15 minutes at −10° C., added with the solution of 2-(2-tert-butoxycarbonylamino-ethyl)-4-phenyl-1H-pyrrole-3-carboxylic acid ethyl ester (0.36 g, 1 mmol) in dichloromethane (2 ml) while maintaining the temperature at −10° C.˜0° C. for 1 hour. Then 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)-5-formyl-4-phenyl-1H-pyrrole-3-carboxylic acid ethyl ester (309 mg, 81.9%) as a red oil.

Provenance & Evidence