Trifluoroacetylation at the 3 Position of 1-(2-Aminophenyl)-2,5-dimethylpyrrole in Trifluoroacetic Acid. Possible Remote Control of an Amino Group in Electrophilic Substitution

Spontaneous trifluoroacetylation at the β position of the pyrrole ring in 1-(2-aminophenyl)-2,5-dimethylpyrrole (1) was observed in trifluoroacetic acid. The half-life of the reaction was about 3.5 h at 25 °C. This unexpected result might be explained in terms of the 1,5-participation of the amino group in the electrophilic substitution reaction.