Green and Mechanochemical One-Pot Multicomponent Synthesis of Bioactive 2-amino-4H-benzo[b]pyrans via Highly Efficient Amine-Functionalized SiO₂@Fe₃O₄ Nanoparticles

Abstract

An ecofriendly, magnetically retrievable amine-functionalized SiO2@Fe3O4 catalyst was successfully synthesized and affirmed by several physicochemical characterization tools, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), energy-dispersive X-ray spectroscopy (EDX), and powder X-ray diffraction. Thereafter, the catalytic performance of this environmentally benign NH2@SiO2@Fe3O4 catalyst was investigated in the one-pot multicomponent synthesis of 2-amino-4H-benzo­[b]­pyran derivatives. The reaction was simply achieved by grinding of various substituted aromatic aldehydes, dimedone, and malononitrile at room temperature under solvent and waste-free conditions with excellent yields and high purity. Moreover, the developed catalyst not only possesses immense potential to accelerate the synthesis of bioactive pyran derivatives but also exhibits several remarkable attributes like broad functional group tolerance, durability, improved yield, reusability, and recyclability. Besides, various other fascinating advantages of this protocol are milder reaction conditions, cost effectiveness, short reaction time, and simple work up procedures.

Efficient N-formylation of primary aromatic amines using novel solid acid magnetic nanocatalyst

“…4a displayed Bragg peaks at 2q ¼ 30.3, 35.6, 43.3, 57.4, 62.9 , which are attributed to (2 2 0), (3 1 1), (4 0 0), 5 1 1, and (4 4 0) crystallographic faces of magnetite, respectively. 34 Similar peaks were obtained for NP@SO 3 H (Fig. 4b), which indicated the retention of crystalline magnetic core aer silica coating and fabrication with various functional groups.…”

“…The amine functionalized silica coated nanoparticles (ASMNPs) were prepared as per our previous report. 34 Briey magnetic nanoparticles (MNPs) were prepared by co-precipitation method. Then these MNPs were coated with dense layer of silica by sol-gel approach to avoid leaching of iron from the core and obtain silica coated magnetic nanoparticles (SMNPs).…”

“…Our research group is working on designing inorganicorganic hybrid magnetic nanocatalyst for catalytic activity. In continuation of our research work, 34 we are here reporting an efficient, mild and green method for the N-formylation of amines with formic acid using NP@SO 3 H as a newer catalyst comprising of sulfonic acid over biguanidine moieties.…”

Nano-SiO2/DBN: An efficacious and reusable catalyst for one-pot synthesis of tetrahydrobenzo[b]pyran derivatives

“…[Bmim]Sac [15], MNPs-PhSO 3 H [16], NH 2 @SiO 2 @Fe 3 O 4 MNPs [17], choline chloride-oxalic acid [18], SCMNPs@PC/VB1-Zn [19], MMWCNTs-D-(CH 2 )4-SO 3 H [20] and Chlorophyll [21]. In this research a practical, simple and inexpensive procedure for the synthesis of tetrahydrobenzo[b]pyran derivatives is reported by the reaction of aldehydes, malononitrile and dimedone in the presence of catalytic amount of nano-silica supported 1,5-diazabicyclo[4.3.0]non-5-en (Nano-SiO 2 /DBN).…”

Novel bisbenzopyronopyran derivatives: photochemical synthesis and their in‐vitro antimicrobial studies

“…[ 9–11 ] These molecules form the structural motif of several synthetic as well as naturally occurring biologically active products including antibiotics, pheromones, alkaloids, and iridoids. [ 12–14 ] The pyran ring systems are extensively dispersed in the plants and animal kingdom. These are utilized as the fragrant preservatives in cosmetics and food stuffs.…”