A study of the Friedel-Crafts acylation of 1-benzenesulfonyl-1H-pyrrole in the preparation of 3-aroylpyrroles

Article abstract of DOI:10.1002/jhet.5570350619

In this work, we studied the aluminum chloride catalyzed reaction of 1- benzenesulfonyl-1H-pyrrole with a series of eleven aroyl chlorides. The products formed were not isolated, but hydrolyzed to the target 3- aroylpyrroles in overall yields, usually, higher than 50%. However, in the CaSeS with the π electron rich 1-phenyl-1H-pyrrole-3-carbonyl chloride and 1-methyl-1H-indole-3-carbonyl chloride significant C-2 substitution occured, resulting in the isolation of the corresponding 1-benzenesulfonyl-2- aroylpyrroles as the predominant or the sole products. The desired C-3 isomers were synthesized starting with 1-triisopropylsilanyl-1H-pyrrole.