Preparation of Core/Shell CaO@SiO2-SO3H as a Novel and Recyclable Nanocatalyst for One-Pot Synthesize of Dihydropyrano[2,3-c]Pyrazoles and Tetrahydrobenzo[b]Pyrans

An overview of recent advances in the catalytic synthesis of substituted pyrans

“…A new acid catalyst, CaO@SiO 2 ‐SO 3 H, was developed by Sameri et al [ 94 ] for the synthesis of tetrahydrobenzopyrans and dihydropyrano[2,3‐c]pyrazoles. The catalyst was prepared by stabilizing of sulfonic acid on the surface of SiO 2 ‐coated CaO NPs and was well characterized by several techniques, namely, Fourier transform‐infrared (FT‐IR), X‐ray diffraction analysis (XRD), field emission scanning electron microscope (FE‐SEM), energy dispersive X‐ray spectroscopy (EDS), wavelength dispersive X‐ray analysis (WDX), and thermogravimetric analysis (TGA).…”

Zn (II)‐Schiff base covalently anchored to CaO@SiO2: A hybrid nanocatalyst for green synthesis of 4H‐pyrans

“…[ 24 ] Silica‐coated CaO nanoparticles were prepared by the Stober method. [ 22 ] Briefly, nano‐CaO (1 g) was sonicated in a mixture of ethanol (40 ml), deionized water (6 ml), and 1.5 ml of 25 wt% concentrated aqueous ammonia for 20 min at room temperature. Then, 1.4 ml of tetraethyl orthosilicate (TEOS) was added and the resulting mixture stirred for 22 h at room temperature under N 2 atmosphere.…”

“…( C) M.P (Lit.) ( C) [38] 22 3-OEt-4-OHC 6 H 3 7 h 20 95 187-189 186-190 [37] 23 2-naphthaldehyde 7i 25 90 196-197 205-207 [41] 24 terephthalaldehyde 7j 40 85 235-237 236-238 [42] 25 [ [22] 30 1-naphthaldehyde 8e 20 93 213-215 214-215 [45] 31 Pyridine-4-carbaldehyde 8f 20 95 260-262 265-266 [46] 32 2,2 0 -(butane-1,4-diylbis (oxy) dibenzaldehyde 8 g 25 95 209-211 209-211 [22] 33 [ comparable, suitable, and efficient catalyst for the synthesis of desired 4H-pyrans. The application of CaO@SiO 2 -NH 2 -Sal-Zn as a hybrid catalyst in solvent-free medium at room temperature led to the greener condition for this synthetic protocol.…”

“…These compounds perform diverse therapeutic activities, such as anti-inflammatory, spasmolytic, antimicrobial, anticoagulant, anticancer, and anti-anaphylactic properties. [18][19][20] Based on the above considerations and also due to our interests in synthesis of heterocyclic compounds, [21][22][23] we wish to report an environmentally benign procedure for synthesis of some dihydropyrano[c]chromenes, dihydropyrano [3,2-c]pyrazoles and tetrahydrobenzo[b] pyrans, via one-pot three-component reactions of related materials in the presence of a novel prepared CaO@SiO 2 -NH 2 -Sal-Zn hybrid nanomaterial as an efficient and green catalyst (Scheme 1).…”

Functionalized hybrid magnetic catalytic systems on micro- and nanoscale utilized in organic synthesis and degradation of dyes

“…Moreover, for the synthesis of benzo [4,5]imidazo[1,2-a]pyrimidine derivatives at 110 C under solvent-free conditions, 95% yield was obtained. Signicantly, phthalazine-trione derivatives are well-known heterocycles used in the pharmaceutical and biological elds including vaso-relaxants, 190 antifungal, 191 antimicrobial, 192 anti-cancer, 193 and anti-inammatory agents. 194 Besides, benzo [4,5]imidazo [1,2-a]pyrimidines are biologically related fused pyrimidine derivatives, which demonstrate highlighted therapeutic and biological characteristics such as antimicrobial, 195 anti-inammatory, 196 protein kinase inhibitor, 197 and anticancer.…”