Abstract:
Nanocrystalline ZSM-5 and Beta zeolites were evaluated as catalysts for the one-pot synthesis of a wide range
of five-, six-, and seven-membered heterocyclic compounds.
Seven-membered compounds were prepared by the reaction of o-phenylenediamine and ketones, whereas five-membered compounds were obtained when o-aminothiophenol
was reacted with ketones under the same reaction condition. Several other seven-membered compounds were prepared by the reaction of (E)-chalcone with o-phenylenediamine/o-aminothiophenol, whereas the six-membered compounds described in this study were prepared by the reaction of o-phenylenediamine with 2-bromoacetophenone/2-
hydroxy acetophenone. Two other five-membered compounds were prepared by the reaction of aniline with benzaldehyde and thioglycolic acid, and the reaction of glycerol
with acetone. The mechanisms responsible for the formation
of the different products were elucidated based on the results of time-dependent 1H NMR experiments. To the best of
our knowledge, this work represents the first reported systematic assessment of the catalytic activity of nanocrystalline
zeolites for the synthesis of heterocyclic compounds. Notably, the catalysts were readily recovered and reused without
any considerable decrease in their catalytic activity. The high
eco-scale score and low E-factor value of this process clearly
demonstrate that it represents a green and sustainable synthetic route for the preparation of a wide range of heterocyclic compounds of significant industrial importance.
