β-cyclodextrin-polyurethane polymer: A neutral and eco-friendly heterogeneous catalyst for the one-pot synthesis of 1,4-dihydropyridine and polyhydroquinolien derivatives via Hantzsch reaction under solvent-free conditions

Abstract

An efficient synthesis of 1,4-dihydropyridine and polyhydroquinoline derivatives using a β-cyclodextrin-polyurethane polymer (β-CDPU) as a stationary micro-vessel and neutral heterogeneous catalyst via a four component coupling of aldehydes, β-ketoester (2 mol) and ammonium acetate under solvent-free conditions is described. Compared with the classical Hantzsch reaction, this new method has the advantages of good yield, short reaction time and methodological simplicity. β-CDPU was proved to be an efficient heterogeneous catalyst that could be easily handled and removed from the reaction mixture by simple filtration, and also recovered and reused without loss of reactivity.

Hyper-cross-linked β-cyclodextrin nanosponge: a three-dimensional, porous and biodegradable catalyst in the one-pot synthesis of kojic acid-based heterocyclic compounds

“…Bearing these facts in mind and in continuation of our former works for the preparation and characterization of a series of biocompatible nanocatalysts and evaluation of their catalytic activates in the synthesis of bioactive heterocyclic compounds [2,32], very recently we successfully synthesized β-cyclodextrin-based nanosponge with carbonate crosslinking agent and investigated its application as a biodegradable porous three-dimensional nanocatalyst in the one-pot synthesis of N-containing organic scaffolds [33]. Herein, we wish to examine the catalytic activity of this polycarbonate nanosponge in the one-pot multi-component synthesis of kojic acid-based heterocyclic compounds.…”

Synthesis of heterocyclic compounds via Michael and Hantzsch reactions

“…1,4‐Dihyropyridines 9 were prepared by a three‐component reaction of aldehydes 1 , 1,3‐diketone or β ‐diketoester 3 , and ammonium acetate or ammonium carbonate in different media (Methods A‐V, Scheme , Table ) …”

“…90%-98% Kuraitheerthakumaran et al [50] G ( R 2 = OEt, R 82%-95% Siddaiah et al [52] I ( R 2 = OEt, R 86%-96% Kiasat et al [53] J ( R 2 = Et, R 69%-87% Sebagai et al [54] K ( R 2 = OEt, R 76%-91% Srinivasan et al [55] L ( R 2 = OEt, R 84%-94% Sohal et al [58] O…”

Polyethylene Glycol‐(N‐Methylimidazolium) Hydroxide‐Grafted γ‐Fe2O3@HAp: A Novel Nanomagnetic Recyclable Basic Phase‐Transfer Catalyst for the Synthesis of Tetrahydrobenzopyran Derivatives in Aqueous Media

“…Both homogeneous and heterogeneous PTCs improve the contact between inorganic reagents and organic substrates, but one of the major problems associated with the use of homogeneous catalysts is the recovery of the catalyst from the reaction medium. Immobilization of the PTC on an insoluble matrix can provide a simple solution to this problem …”