Silver nanoparticles-decorated Preyssler functionalized cellulose biocomposite as a novel and efficient catalyst for the synthesis of 2-amino-4H-pyrans and spirochromenes

Abstract

Silver nanoparticles-decorated Preyssler functionalized cellulose biocomposite (PC/AgNPs) was prepared and fully characterized by FTIR, UV–vis, SEM, and TEM techniques. The preparation of PC/AgNPs was studied systematically to optimize the processing parameters by Taguchi method using the amount of PC, reaction temperature, concentration of silver nitrate and pH of medium. Taguchi’s L9 orthogonal (4 parameters, 4 level) was used for the experimental design. The SEM analysis confirmed the presence of the Preyssler as a white cloud as well as spherical AgNPs on the surface of cellulose. The formation of AgNPs on the surface was observed by changing of the color from yellow to deep brown and confirmed by UV–vis spectroscopy. The best yield of AgNPs forming was obtained in pH 12.5 at 80 ºC in 20 min. TEM analysis confirmed the formation of spherical AgNPs with a size of 50 nm, at the 1% wt. loading of Preyssler. This easily prepared PC/AgNPs was successfully employed as an efficient, green, and reusable catalyst in the synthesis of a wide range of 2-amino-4 H -pyran and functionalized spirochromene derivatives via a one-pot, multicomponent reaction. The chief merits realized for this protocol were the utilization of commercially available or easily accessible starting materials, operational simplicity, facile work-up procedure, obtaining of high to excellent yields of the products and being done under green conditions. The catalyst could be easily separated from the reaction mixture and reused several times without observing any appreciable loss in its efficiency.

Chitosan-EDTA-Cellulose network as a green, recyclable and multifunctional biopolymeric organocatalyst for the one-pot synthesis of 2-amino-4H-pyran derivatives

“…A simple and general protocol for preparation of 2-amino-4 H -pyran derivatives involves a three-component one-pot cyclocondensation of ethyl acetoacetate, malononirilel/alkyl cyanoacetate and various carbonyl compounds. Several modified methods have been reported using different homogeneous or heterogeneous catalysts such as uera-chCl 55 , potassium phthalimide- N -oxyl 56 , potassium phthalimide under ball-milling 57 , Et 3 N under sonication 54 , CuFe 2 O 4 @starch 58 , CoFe 2 O 4 -Cell/Fe (III) SSZ 59 , KF-Al 2 O 3 60 , Fe 3 O 4 /EDTA 61 , γ-Fe 2 O 3 -Im-Py) 2 WO 4 62 , amine-functionalized SiO 2 @Fe 3 O 4 63 , water extract of red mud 64 , sodium alginate 13 , 14 , isocyanurate-based periodic mesoporous organosilica 65 and silver nanoparticles-decorated Preyssler functionalized cellulose 66 in recent years. In continuation of our research group to expand the catalytic activity of pristine or modified biopolymers for different MCRs 10 – 14 , 32 , 67 , 68 , this report presents the use of Cs-EDTA-Cell as a biopolymer nanocatalyst for the synthesis of 2-amino-4 H -pyran derivatives (Fig.…”

Chitosan‐ZnO: An Efficient and Recyclable Polymer Incorporated Hybrid Nanocatalyst to Synthesize Tetrahydrobenzo[b]pyrans and Pyrano[2,3‐d]pyrimidinones under Microwave Expedition

“…Literature survey revealed that homogeneous catalytic reactions have been analyzed to establish methodologies in which the use of metal nanoparticles supported onto polymers owing to their specificity towards attracting the metal nanoparticles [2,3] . Accumulation of nanoparticles over the surface of biopolymers is a leading area of research due to their potential applications in electronic devices, sensing, catalysis and bio‐medicalsciences [4] . The synthesis of metal oxide nanoparticals particularly zinc oxide nanocomposites (NCs) is an emerging research area in nanotechnology [5–7] .…”

“…[2,3] Accumulation of nanoparticles over the surface of biopolymers is a leading area of research due to their potential applications in electronic devices, sensing, catalysis and bio-medicalsciences. [4] The synthesis of metal oxide nanoparticals particularly zinc oxide nanocomposites (NCs) is an emerging research area in nanotechnology. [5][6][7] Over the years, synthesis of nanomaterials and NCs has been of great concern but there is an increasing need for the advancement of more efficient, facile and environmentally benign methods.…”

Ultrasound-Promoted preparation and application of novel bifunctional core/shell Fe 3 O 4 @SiO 2 @PTS-APG as a robust catalyst in the expeditious synthesis of Hantzsch esters

“…[33] In these reactions (domino processes), several starting materials (more than two reactants) react simultaneously and in one step at the presence of a catalyst and produce the desired product [34][35][36][37]. Multi-component reactions have unique advantages, such as the production of complex and diverse products through the formation of several bonds during an operation, without the need to isolate and purify the intermediates with high e ciency and high selectivity in the shortest time, together with the high atomic economy, therefore, they prevent the production of side and waste products during the reaction [38][39][40][41]. Polyhydroquinoline (PHQ) and 1,4-dihydropyridine (1,4-DHP) derivatives are some of the most important and oldest multicomponent reactions that were rst reported in 1882 by a German chemist named Arthur Hanztsch [42][43][44].…”