Improvements in the acylation of 3-methylindole using amberlyst-15

Abstract

A simple and efficient methodology for Friedel-Crafts acylation of 3-methylindole using Amberlyst 15 resin as catalyst is described. This methodology shows good selectivity towards the for-mation of the products of 2-acylation, (3-methyl-1H-indol-2-yl)ketones. Several advantages can be as-cribed to Amberlyst 15, among them; are the ease of handling, quick separation from the reaction mix-ture and minimum or no production of the chemical residues that must be eliminated. Besides, the catalyst can be easily recycled and reused with a minimal loss in activity through 6 reaction cycles. The catalyst was characterized by FT-IR spectroscopy and superficial acidity.