Using magnetic nanoparticles Fe3O4 as a reusable catalyst for the synthesis of pyran and pyridine derivatives via one-pot multicomponent reaction

Abstract

In recent years, several methods and developments have been reported for the synthesis of pyran and pyridine [13][14][15][16][17] derivatives; each has its own merits and drawbacks. Many of the standard procedures require long reaction times, harsh reaction conditions, expensive and toxic reagents, solvents, and tedious work-up procedures. Moreover in some cases, a mixture of products is obtained, needing cost-effective column chromatography, naturally resulting in low yields. Heterogeneous catalysis is of supreme importance in many areas of the chemical and energy consuming industries [18,19].Conducting the reactions, using heterogenous catalysts should compensate some of drawbacks observed in previously reported reactions. In this kind of reaction, the catalyst can be separated by filtration. However, it is worthy to mention in spite of several advantages, experienced, practically in using of heterogenous catalysts, due to the nanosized particles used, few limitations to the sustainability are observed [20].To get around these problems, the use of a heterogeneous catalyst which can be separated practically other than filtration is desirable. Magnetite nanoparticles (Fe 3 O 4 ) have attracted much attention in the past decade, due to their unique features, including, low preparation cost, high thermal and mechanical stability, and adaptability for largescale production. In addition, their paramagnetic nature allows their facile and effective separation from the reaction mixture, without using standard filtration, required in separation of heterogeneous catalysts. Magnetite nanoparticles (Fe 3 O 4 ) can be easily separated from reaction mixture by using just an external magnet [21].Thus, in recent years, nano-Fe 3 O 4 [22] has attracted a great attention as heterogeneous catalyst [23] due to its simple handling, easy of recovery with an external magnetic field [24,25]. Magnetic nanoparticles (MNPs) have Abstract An atom-economical, efficient and mild protocol is described for the synthesis of 2-amino-3-cyanopyridine and 2-amino-3-cyano-4H-pyran derivatives in the presence of high surface area Fe 3 O 4 as a highly effective heterogeneous catalyst via one-pot multicomponent cyclocondensation reaction.

Experimental and theoretical studies of the nanostructured {Fe3O4@SiO2@(CH2)3Im}C(CN)3catalyst for 2-amino-3-cyanopyridine preparationviaan anomeric based oxidation

“…Among the pyridine ring systems which present varied chemotherapeutic and pharmacological applicabilities [4][5][6], 2-amino-3-cyanopyridines raised substantial medicinal and synthetic attentionssince this widespread heterocycle molecules allowed an access to many demonstrated bio-active species such as IKK-b inhibitors [7], A 2A adenosine receptor antagonist [8], and potent inhibitor of HIV-1 integrase [9]. Hence, in consequence of the aforementioned biological significances of these versatile structural motifs, a number of procedures have been reported on this topic like microwave or ultrasound irradiation [10][11][12][13], hexadecyldimethyl benzyl ammonium bromide and triethylamine [14], DMF [15], acetic acid [16], Fe 3 O 4 [17], Cellulose-SO 3 H [18]and using earth Lewis acid catalyst [19]. Although, several catalyst and protocol have been studied for the preparation of the 2-amino-3-cyanopyridine derivatives, the methods suffer from one or more imperfection such as toxic solvent like benzene [20], multi-steps reaction pathway [21], high temperature and microwave assistance [22,23], prolonged reaction times and harsh reaction conditions with low yields.…”

3‐Amino‐5‐mercapto‐1,2,4‐triazole‐functionalized Fe3O4 magnetic nanocomposite as a green and efficient catalyst for synthesis of bis(indolyl)methane derivatives

“…Recently, some MNPs have been used as highly useful supports for immobilization of homogeneous catalysts in order to obtain heterogeneous catalysts and enable them to be recovered using an external magnet 13–15 . Among MNP materials, magnetite (Fe 3 O 4 ) has received more attention in biomedical and chemical fields because of its unique physical and chemical properties 16, 17 . Hopping of electrons between Fe 2+ and Fe 3+ results in development of the magnetic properties of Fe 3 O 4 18 .…”

A convenient method for preparation of 2-amino-4,6-diphenylnicotinonitrile using HBF4 as an efficient catalyst via an anomeric based oxidation: A joint experimental and theoretical study

“…The 2amino-4,6-diphenylnicotinonitrile derivatives contain pyridine ring systems which possess wide chemotherapeutic and pharmaceutical applications such as IKK-b inhibitors [14], A 2A adenosine receptor antagonists [15], and potent inhibitors of HIV-1 integrase [16]. As a consequence of the biological and therapeutic significance of these heterocyclic molecules, a number of methods have been developed for their preparation [17][18][19][20][21][22][23][24][25].…”