Graphene oxide–chitosan bionanocomposite: a highly efficient nanocatalyst for the one-pot three-component synthesis of trisubstituted imidazoles under solvent-free conditions

Abstract

In the present work, a green, rapid, convenient and eco-friendly method for the synthesis of 2,4,5-trisubstituted imidazoles is described. In this method, we used 1,2-diketone or a-hydroxy ketone, an aldehyde and ammonium acetate in the presence of graphene oxide-chitosan bionanocomposite, which acted as an efficient nanocatalyst. This protocol has many advantages such as short reaction time, high yield, easy separation of the catalyst and solvent-free condition. We used differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and atomic force microscopy (AFM) to confirm that the nanocomposite was formed, and FT-IR, 1 H and 13 C NMR analyses were performed for the confirmation of the synthesized products.Scheme 2 Proposed mechanism for the synthesis of substituted imidazoles 4a-o. Fig. 5 Reusability of GO-chitosan for the synthesis of 2,4,5-triphenyl-1H-imidazole 4a. 33182 | RSC Adv., 2015, 5, 33177-33184 This journal is

Sonochemical synthesis of chromenes catalyzed by L-phenyl alanine-attached nano-Fe3O4@SiO2

“…(TON/TOF (min −1 ) = 9300/ 1550). A probable mechanism for the reaction using nano- (40,41). Nanoparticles exhibit good catalytic activity due to their large surface area and active sites which are mainly responsible for their catalytic activity.…”

Green synthesis of polyhydroquinolines via MCR using Fe3O4/SiO2-OSO3H nanostructure catalyst and prediction of their pharmacological and biological activities by PASS

“…Fe 3 O 4 /SiO 2 -OSO 3 H nanocomposite was prepared according to our previous reports using FeCl 2 and FeCl 3 , tetraethyl orthosilicate (TEOS) as main starting materials, and then sulfonation by ClSO 3 H in an ice bath, and then, stirring at room temperature [18].…”

“…Multicomponent reactions (MCRs) could provide facile, efficient and practical methods in modern medicinal and combinatorial chemistry for the construction of molecular complexity and structural diversity because they have significant features such as simple design, atom-economy, environmental benignity and the possibility to construct target compounds using several assorted elements through one-pot processes and simple chemical procedures [1][2][3][4][5].…”

Green multicomponent synthesis of four different classes of six-membered N-containing and O-containing heterocycles catalyzed by an efficient chitosan-based magnetic bionanocomposite

“…In continuation of our research to find sustainable and green routes for synthesis of chemically and biologically-important molecules and application of efficient and green catalysts in various organic reactions [9,[23][24][25][26][27][28], and due to the disadvantages of previously reported methods for synthesis of many class of heterocycles despite their valuable properties, we present a green and efficient synthesis method for synthesis of some nitrogen and oxygen containing heterocycles using a magnetic bionanocomposite, CuFe 2 O 4 /chitosan, as a recyclable and green catalyst. To the best of our knowledge, this is the first time that CuFe 2 O 4 /chitosan has been applied as catalyst for synthesis of these classes of heterocycles.…”