Glycolic acid‐supported cobalt ferrite‐catalyzed one‐pot synthesis of pyrimido[4,5‐b]quinoline and indenopyrido[2,3‐d]pyrimidine derivatives

Abstract

Herein, one‐pot synthesis of pyrimido[4,5‐b]quinoline and indenopyrido[2,3‐d]pyrimidine derivatives was developed by the three‐component reaction of aldehydes, 6‐amino‐1,3‐dimethyluracil, and 1,3‐dicarbonyl compounds in the presence of glycolic acid‐supported cobalt ferrite CoFe2O4@SiO2@Si (CH2)3NHCOOCH2COOH as a novel magnetic catalyst in ethanol at reflux conditions. Glycolic acid‐supported cobalt ferrite was characterized via Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy‐dispersive X‐ray spectroscopy (EDX), and vibrating sample magnetometer (VSM). Moreover, the catalyst was easily recovered with magnetic separation and recycled at least for five times without significant loss of its catalytic activity. The products were formed in excellent yields over appropriate reaction times under environmentally friendly conditions. The high efficiency and easy isolation of catalyst from products with an external permanent magnet are some of the remarkable advantages of this method.

Synthesis of Novel Pyrimido[4,5-b] Quinolines Containing Benzyloxy and 1,2,3-Triazole Moieties by DABCO as a Basic Catalyst

“…In a mechanism which is supported by the previous literature, − dimedone converts into the enol form by the tautomerization and then DABCO attracted one proton from the hydroxyl group to obtain 5,5-dimethyl-3-oxocyclohex-1-enolate. In the next step, the prepared enolate attacked to aldehyde which is activated by protonated DABCO and lost a molecule of water to generate ( I ) as an intermediate.…”

“…According to the importance of the mentioned pyrimido[4,5- b ]quinolines, various catalysts were reported for the multi-component synthesis of pyrimido[4,5- b ]quinolines such as [TSSECM], 1 SBA-15/PrN(CH 2 PO 3 H 2 ) 2 , 23 [H 2 -DABCO][ClO 4 ] 2 , 24 nano-[Fe 3 O 4 @SiO 2 / N -propyl-1-(thiophen-2-yl)ethanimine][ZnCl 2 ], 25 nano-[Fe 3 O 4 @-SiO 2 @R-NHMe 2 ][H 2 PO 4 ], 26 Fe 3 O 4 @Cellulose sulfuric acid, 27 N , N -diethyl- N -sulfoethanaminium chloride, 28 [bmim]Br, 29 glycolic acid-supported cobalt ferrite, 30 nanocrystalline MgO, 31 [C 4 (DABCO) 2 ]·2OH, 32 and agar-entrapped sulfonated DABCO. 33 However, most of the proposed methods are performed by acidic and expensive catalysts.…”

Silica supported spinel structured cobalt ferrite multifunctional nanocatalyst for hydration of nitriles and oxidative decarboxylation of phenylacetic acids

“…These observations showed the presence of Co +2 in the compound. [ 61,62 ] The core‐level spectrum (Figure 3b) for Fe 2p was characterized by a pair of peaks corresponding to the 3/2 and 1/2 spin‐orbit components located at 711.9 eV and 725.5 eV, respectively, and are accompanied by a satellite peak (S 1 ) at 716.1 eV confirming the presence of Fe +3 oxidation state in the compound. [ 44,63 ] The above results confirmed the formation of CoFe 2 O 4 spinel.…”

“…[ 66 ] Finally, at a temperature above 600°C, no appreciable weight loss was observed indicating the existence of CoFe 2 O 4 @SiO 2 nanoparticles. [ 62 ]…”

“…[66] Finally, at a temperature above 600 C, no appreciable weight loss was observed indicating the existence of CoFe 2 O 4 @SiO 2 nanoparticles. [62] F I G U R E 6 N 2 adsorption-desorption isotherm of CoFe 2 O 4 @SiO 2 F I G U R E 7 Magnetic hysteresis loop of CoFe 2 O 4 @SiO 2…”