Superparamagnetic nanoparticles as a recyclable catalyst: a new access to phenol esters via cross dehydrogenative coupling reactions

Abstract

CuFe 2 O 4 superparamagnetic nanoparticles were utilized as a recyclable heterogeneous catalyst for the direct synthesis of chemical structures containing both phenol ester and benzothiazole moieties via cross dehydrogenative coupling reactions. Several substrates were reactive towards the transformation in the presence of the nano catalyst, including benzaldehyde, benzyl alcohol, dibenzyl ether, 2-oxo-2-phenylacetaldehyde, and 2-iodo-1-phenylethanone. This nano catalyst displayed higher catalytic efficiency than many homogeneous and heterogeneous catalysts. The nano CuFe 2 O 4 was easily isolated by using a magnet, and reutilize numerous times without a remarkable deterioration in catalytic performance. To our best knowledge, these reactions were not previously reported in the literature.

Two different facile and efficient approaches for the synthesis of various N-arylacetamides via N-acetylation of arylamines and straightforward one-pot reductive acetylation of nitroarenes promoted by recyclable CuFe2O4 nanoparticles in water

“…Furthermore, compared with iron oxides, spinel ferrites provide flexibility to control both crystal structures and magnetic properties by choosing different non-iron metals in spinel ferrite backbone and controlling their molar concentrations. Among various type of spinel ferrite magnetic nanoparticles (MNPs), CuFe 2 O 4 nanocomposite, in addition to numerous applications, has shown satisfactory performance as the recyclable catalyst in various organic transformations such as synthesis of heterocyclic compounds [46][47][48][49][50][51][52], Ullmann C-O coupling reaction [53], direct synthesis of chemical structures containing both phenol ester and benzothiazole moieties via dehydrogenative coupling reactions [54], reduction of p-nitrophenol [55], one-pot odorless carbon-sulfur bond formation reactions [56], directed phenol/formamide coupling [57], synthesis of diaryl/aryl alkyl sulfides via cross-coupling process [58], S-arylation of thioureas by aryl halides [59], one-pot four-component Dakin-West reaction (synthesis of β-acetamido ketones) [60], Friedel-Crafts acylation [61], N-arylation of heterocycles [62], direct C-H amination of benzothiazoles [63], oxidative hydroxylation of arylboronic acids [64], palm oil methanolysis [65], oxidation of benzyl alcohol [66], synthesis of unnatural arundines [67], N-arylation of indole and imidazole with aryl halide [68], and so on.…”

Fe3O4@vitamin B1 as a sustainable superparamagnetic heterogeneous nanocatalyst promoting green synthesis of trisubstituted 1,3‐thiazole derivatives

“…Surface functionalization of magnetic nanoparticles (MNPs) is a well‐designed way to bridge the gap between heterogeneous and homogeneous catalysis . Organocatalysts contain a homogeneous part whereby starting materials are easily converted to the desired products(s), and the heterogeneous part of these advanced catalysts can be separated easily using an external magnet . Thus, high conversions in reaction and easy work‐up procedures allow the preparation of desired compounds in high pure isolated yields …”