Preparation, Characterization and First Application of Aerosil Silica Supported Acidic Ionic Liquid as a Reusable Heterogeneous Catalyst for the Synthesis of 2,3-Dihydroquinazolin-4(1H)-ones

Abstract

A new heterogeneous acidic catalyst was successfully prepared by impregnation of silica (Aerosil 300) by an acidic ionic liquid, named 1-(4-sulfonic acid)butylpyridinium hydrogen sulfate [PYC 4 SO 3 H][HSO 4 ], and characterized using FT-IR spectroscopy, the N 2 adsorption/desorption analysis (BET), thermal analysis (TG/ DTG), and X-ray diffraction (XRD) techniques. The amount of loaded acidic ionic liquid on Aerosil 300 support was determined by acid-base titration. This new solid acidic supported heterogeneous catalyst exhibits excellent activity in the synthesis of 2-aryl-2,3-dihydroquinazolin-4(1H)-ones by cyclocondensation reaction of 2-aminobenzamide with aromatic aldehydes under solvent-free conditions and the desired products were obtained in very short reaction times with high yields. This catalyst has the advantages of an easy catalyst separation from the reaction medium and lower problems of corrosion. Recycling of the catalyst and avoidance of using harmful organic solvent are other advantages of this simple procedure.

Magnetically separable modified sulfuric acid (CuFe2O4@SiO2-OSO3H): Preparation, characterization and catalytic application for the synthesis of 1,8-dioxo-octahydroxanthenes

“…In this view and in line with our interest in the application of reusable catalysts in organic reactions [41][42][43][44][45][46][47] and in continuation of our previous works in the synthesis of new MNPs [48,49], we report the preparation of SO3Hfunctionalized magnetic core-shell nanoparticles, CuFe2O4@SiO2-OSO3H, by coating a SiO2 shell around CuFe2O4 MNPs followed by immobilization of sulfuric acid (Scheme 1). The catalytic activity of the prepared heterogeneous and green acidic magnetic nanocatalyst was tested in the synthesis of 1,8-dioxooctahydroxanthenes 3a-j by the reaction of aromatic aldehydes 2a-j with dimedone 1 under solvent-free conditions (Scheme 2).…”

Phosphomolybdic acid supported on Schiff base functionalized graphene oxide nanosheets: Preparation, characterization, and first catalytic application in the multi‐component synthesis of tetrahydrobenzo[a]xanthene‐11‐ones

“…Taking all these facts into consideration, and in line with our interest in catalysis, [50][51][52][53][54][55][56][57] in this paper, for the first time, a new SB functionalized GO containing a phosphomolybdic counter-anion H 2 PMo 12 O 40¯( H 2 PMo) was prepared by grafting of APTS on GO nanosheets followed by condensation with benzil and finally reaction with phosphomolybdic acid (H 3 PMo 12 O 40 , denoted as H 3 PMo) and fully characterized (Scheme 1). The catalytic activity of this new material which was denoted as GO-SB-H 2 PMo was also investigated in one-pot synthesis of tetrahydrobenzo[a]xanthene-11-ones by reaction of βnaphthol, aldehydes, and dimedone (Scheme 2).…”

One-pot Synthesis of 2,3-Dihydroquinazolin-4(1H)-ones under Catalyst- and Solvent-free Conditions

“…26 All of these reactions are successful in producing the target compound although certain drawbacks, such as use of harmful solvents, expensive catalysts, and low yields, are associated with some of them. With the goal of making some of the above-mentioned methods benign, the reactions were carried out under solvent-free conditions 16,20,21 , using MW-irradiation 21,22 and of water 18,22,24,25 or ethanol 11,12,17,22 as solvents. However, none of them proceeded without the use of catalyst.…”

“…Furthermore, the reaction conditions are sufficiently mild enough to tolerate a variety of functionalities such as Cl, Br, OH, OMe, -OCH 2 O-and NMe 2 . All the products (3) are known compounds and were identified by comparison of their physical and spectral data with those reported in the literature [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]33 . From a mechanistic point of view, the process is possibly a general acidbase catalyzed condensation followed by cyclization 16,20 .…”