Abstract
Polyhydroquinolines were efficiently obtained from a sequential four-component reaction between dimedone or 1,3-cyclohexandione, ethyl acetoacetate, or methyl acetoacetate as a β-ketoester, aldehydes, and ammonium acetate, under the catalysis of Mo@GAA-Fe3O4 MNPs as a green, effective, recyclable, and environmentally friendly nanocatalyst. Due to its magnetic nature the prepared catalyst can be easily separated from the reaction mixture by an external magnet and reused several times without significant changes in catalytic activity and reaction efficiency. The catalyst was characterized using energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM).
Highlights
In recent decades, the preparation of environmentally friendly catalysts with recoverability and reusability are the main challenges amongst researchers in organic chemistry
The main problem when using these catalysts is related to the difficulty in separating and reusing them, which can be largely solved by using heterogeneous types
Many procedures have been developed for the preparation of polyhydroquinolines using catalysts such as ionic liquids,[54] microwaves,[55] re uxing at high temperature,[56] metal tri ates,[57] ceric ammonium nitrate (CAN),[58] trimethylsilyl chloride (TMSCl),[59] HY-zeolite,[60] FeF3,61 silica perchloric acid (HClO4–SiO2),[62] tri uoroethanol,[63] montmorillonite K-10,64 iodine,[65] autoclave,[66] NiFe2O4 magnetic nanoparticles (MNPs),[67] heteropoly acid,[68] Lproline,[69] PTSA-SDS,[70] NiCuMgFe2O4 MNPs,[71] polymers,[72] Sc(OTf)3,73 {Fe3O4@SiO2@(CH2)3Im}C(NO2)[3,74] Yb(OTf)[3,57] Fe3O4-adenine-Ni,[75] BINOL-phosphoric acid derivatives,[76] and CuSPATB/Fe3O4.77 most of these procedures offer distinct merits, some of these procedures suffer from one or more limitations, such as generating a large amount of waste, low yields of the desired product, poor recovery of the catalyst, long reaction times, and hard reaction conditions
Summary
The preparation of environmentally friendly catalysts with recoverability and reusability are the main challenges amongst researchers in organic chemistry. Polyhydroquinoline derivatives are very interesting heterocyclic molecules due to their pharmacological properties such as anti-in ammatory, antimalarial, antibacterial, anti-asthmatic, and tyrosine kinase inhibiting agents.[51,52,53] Many procedures have been developed for the preparation of polyhydroquinolines using catalysts such as ionic liquids,[54] microwaves,[55] re uxing at high temperature,[56] metal tri ates,[57] ceric ammonium nitrate (CAN),[58] trimethylsilyl chloride (TMSCl),[59] HY-zeolite,[60] FeF3,61 silica perchloric acid (HClO4–SiO2),[62] tri uoroethanol,[63] montmorillonite K-10,64 iodine,[65] autoclave,[66] NiFe2O4 MNPs,[67] heteropoly acid,[68] Lproline,[69] PTSA-SDS,[70] NiCuMgFe2O4 MNPs,[71] polymers,[72] Sc(OTf)3,73 {Fe3O4@SiO2@(CH2)3Im}C(NO2)[3,74] Yb(OTf)[3,57] Fe3O4-adenine-Ni,[75] BINOL-phosphoric acid derivatives,[76] and CuSPATB/Fe3O4.77 most of these procedures offer distinct merits, some of these procedures suffer from one or more limitations, such as generating a large amount of waste, low yields of the desired product, poor recovery of the catalyst, long reaction times, and hard reaction conditions To avoid these limitation based on the green chemistry protocols, the discovery of simple, efficient, versatile, and environmentally friendly processes for the synthesis of polyhydroquinolines is still favored. A er 24 h, the Amp@SCMNPs were collected using a permanent magnet, washed with ethanol and distilled water several times, and dried under vacuum
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
