Regioselective N-Acylation of Heterocyclic Amines Under Dry Conditions Catalyzed by a Natural Clay

An environment friendly, general, rapid, and one-pot convenient procedure for N-acylation (acetylation and benzoylation) of nitrogenous heterocyclic compounds have been reported using stoichiometric amounts of heterocyclic amines and acetyl chloride or benzoyl chloride under solvent-free conditions catalyzed by a naturally available reusable clay (clay used by the traditional potters of Assam, India) at room temperature. The general efficiency of the method is evident from the variety of the N-based heterocycles, including both five and six membered rings, resulting in the corresponding N-acyl heterocycles, which react in excellent yields (69-97%) within a very short time (4-35 mins.).