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A new heterogeneous nanocatalyst containing Cu–dimethylglyoxime complex grafted to an MCM-41 matrix was synthesized. This recoverable nanocomposite was applied as a highly effective, green, thermally stable catalyst in the one-pot reductive cyclization of aromatic aldehydes with 2-aminobenzamide. 2,3-Dihydroquinazolin-4(1H)-ones were obtained in 80–98% yield. The MCM-41-silylcyclopropyl-dimethylglyoxime-Cu heterogeneous nanocomposite was well identified using X‐ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, energy‐dispersive X‐ray spectroscopy, Brunauer–Emmett–Teller technique, and thermogravimetric analysis. The eco-friendly nanocatalyst demonstrated excellent recyclability: it could be reused for at least six successive cycles without any notable decrease in its catalytic function. Graphic abstract: [Figure not available: see fulltext.]

A silica-supported iron complex has been identified as a highly active and reusable catalyst for the synthesis of medicinally important 2,3-dihydroquinazolin-4(1H)-ones. The catalyst was fully characterized by various spectroscopic analyses such as Fourie

β-Cyclodextrin, a green and widespread supramolecular catalyst, has been explored as a highly proficient promoter for the metal-free one-pot multi-component synthesis of a vast range of highly functionalized bioactive heterocyclic moiety, 2-amino-4,6-diphenylnicotinonitriles and 2,3-dihydroquinazolin-4(1H)-one, from easily available precursor aldehydes. The main endeavor of these protocols is to explore this organic supramolecule in one-pot multi-component synthesis. Absence of metal catalyst or toxic acid and harsh reaction conditions, excellent functional group tolerance, inexpensive, greener and environmentally safe protocol are the key advantages of this work.

In the present study, a facile technique to immobilize praseodymium(iii) complex on the surface of magnetic nanoparticles by using available materials is reported. The prepared samples were characterized by chemical and physical methods such as FTIR, SEM, XRD and EDX and were tested in the synthesis of polyhydroquinoline and 2,3-dihydroquinazolin-4(1H)-one derivatives. It was observed that the yields of the reactions in the presence of the prepared nanocatalyst were good to excellent. More importantly, the use of a recoverable and novel magnetic nanocatalyst in these reactions is the outstanding feature of this protocol.

Abstract: In the present study, an efficient and magnetically recoverable Br?nsted acid ionic liquid, 1-methyl-3-[3-(triethoxysilyl)propyl]-1H-imidazol-3-ium hydrogen sulfate, immobilized on the surface of Fe3O4?SiO2 magnetic nanoparticles (Fe3O4?SiO2–ImHSO4) has been used for a high-yield synthesis of 2,3-dihydroquinazolin-4(1H)-ones through the condensation of anthranilamide with aldehydes and ketones in EtOH at room temperature or under reflux. The significant features of the present protocol are short reaction times, high yields of products, ecofriendly reaction conditions, simple work-up, and reusability of the catalyst. The catalyst can be simply magnetically recovered and reused at least five times without considerable loss of its catalytic activity.

Graphene-supported sulfonic acid (Gr?SO3H) has been prepared by covalent grafting of (3-mercaptopropyl)trimethoxysilane in the matrix of graphene followed by treatment with sulfuric acid and hydrogen peroxide. Gr?SO3H has been successfully characterized by Fourier transform infrared (FT-IR) spectroscopy, Fourier transform Raman (FT-Raman) spectroscopy, CP-MAS 13C NMR spectroscopy, thermogravimetric analysis (TGA), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, and X-ray diffractometer (XRD) analysis. Gr?SO3H served as a robust heterogeneous catalyst for the synthesis of bioactive 2,3-dihydroquinazolin-4(1H)-ones from anthranilamide and aryl aldehydes in ethanol. Recyclability experiments were executed successfully for six consecutive runs.

Supported ionic liquids (SILs) have attracted rising interest and the subject of active research in the last decades due to the diversified range of applications and yet reports on ILs is still rapidly increasing. This work reports a choline sulfate ionic liquid supported on fascinating and highly stable porous graphitic carbon nitride (g-C3N4) nanosheets as an inexpensive and an environmentally friendly reusable ionic catalyst in organic synthesis typically requiring a harmful organic solvent and highly toxic acids. g-C3N4?SO3Ch was prepared by mixing sulfonic acid functionalized graphitic carbon nitride nanosheets (g-C3N4?SO3H) with choline hydroxide or via a novel approach. The introduction of a choline sulfate could significantly enlarge specific surface areas with rich reaction sites and suppressed the recombination of sheets. This work provides a new way to improve the chemical property of g-C3N4 along with the recyclability of the ionic liquid. g-C3N4?SO3Ch (IL/g-C3N4) offers an effective, reusable, inexpensive, environmentally friendly and low-cost catalyst for the synthesis of 3,4-dihydropyrimidin-2 (1H)-ones, 2,3-dihydroquinazolin-4 (1H)-ones and bisindolylmethanes in good to excellent yields. The prepared catalyst synthesized compounds were well characterized by different techniques such as FT-IR, XRD, SEM, EDX and TGA.

In this research, we have used Fe3O4@nano-cellulose–OPO3H as magnetic bio-based nanocatalyst for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones via condensation of 2-aminobenzamide and different aldehydes. The major advantages of the present methodology are good yields, ecofriendly catalyst, and easy workup.

Ni-PEG (polyethylene glycol) complex supported on magnetic nanoparticle was created by grafting. The catalytic activity of Fe3O4@PEG–Ni was explored through one-pot green synthesis of 2,3-dihydroquinazolin-4(1H)-ones and used as an efficient and recoverable nanocatalyst. FT-IR, XRD, EDS, BET, TGA, VSM and SEM techniques were employed to specify the nanocatalyst. This heterogeneous nanocatalyst demonstrated acceptable recyclability and could be reused several times with no considerable loss of its catalytic activity.

A copper-catalyzed one-pot synthesis of 2,3-dihydroquinazolin-4(1 H)-ones with diboronic acid as a reductant in an aqueous medium is described. Various 2,3-dihydroquinazolin-4(1 H)-ones were prepared with good functional-group tolerance in good yields under mild conditions from readily available 2-nitrobenzonitriles and various carbonyl compounds.

Benzene-1,3,5-tricarboxylic acid-functionalized MCM-41 (MCM-41-Pr-BTA), as a novel hybrid organosilica, was prepared and properly characterized by the Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller, thermal gravimetric analysis and energy-dispersive X-ray spectroscopy to evaluate the functional groups, crystallinity, surface area, morphology, particle size distribution and loading of functional groups. Interestingly, the 1,3-propylene linker used in this study incorporates appropriate catalytic activity into the MCM-41 framework compared to the more known trialkoxypropyl silanes. This new organosilica can be used as a hybrid nanocatalyst for the expeditious and efficient synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives, as an important pharmaceutical scaffold, in aqueous media via a three-component one-pot condensation of isatoic anhydride and aromatic aldehydes with primary amines or ammonium salts. This method has several advantages such as low catalyst loading, high to excellent yields, short reaction times, working under green conditions and simple workup.

A novel protocol for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones from 2-aminobenzamides and aldehyde derivatives catalyzed by KOH/DMSO suspension has been developed. The present transition metal free methodology is operationally simple, scalable and varieties of 2,3-dihydroquinazolin-4(1H)-one derivatives were obtained in good to excellent yields in short reaction times.

A cellulose sulfonate catalyst (HS-cellulose sulfonate) with high stability, excellent catalytic activity and high acidity value (about 1.55 mmol g-1) was successfully prepared by SO3 gas phase sulfonation. The basic morphology and nanostructure of the catalyst were determined by HRTEM, XRD, IR, TG, etc. In addition, the catalyst was applied to the catalytic reaction of a dihydroquinazolinone derivative and a xanthene compound, and very valuable results were obtained. The development and preparation of cellulose sulfonate catalysts provide a good approach for the development and application of cellulose, and also an important application of green organic catalytic synthesis methodology.

In the present work, sulfonated highly ordered mesoporous graphitic carbon nitride (ompg-C3N4/SO3H) was synthesized successfully and employed as an efficient and reusable heterogeneous solid acid catalyst for the rapid and one-pot synthesis of 2,3-dihydroquinazolin-4(1H)-ones via the condensation of anthranilamide with aldehydes or ketones in good to excellent yields. The organocatalyst was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectrometer, Brunauer–Emmett–Teller surface area, and thermal gravimetric and differential thermal analysis. The substantial advantages of this procedure involve short reaction times, high catalytic activity, easy workup, high purity of the products, and easy recovery and reusability of the catalyst.

A facile and highly efficient one-pot synthesis of 2,3-dihydroquinazolin-4(1H)-ones derivatives has been developed by the condensation of anthranilamide with aldehydes using sulfonic acid functionalized l-Proline?Fe3O4 nanoparticles as a catalyst. The advantages of this protocol are easy recovery and reusability of the catalyst besides simple work-up procedure and short reaction time. In addition, the anthelmintic activities of some selective compounds were investigated and it was found that 2-phenyl-2,3-dihydroquinazolin-4(1H)-one exhibited profound anthelmintic activity against two helminth models.

Abstract: Facile and efficient protocols for some multicomponent coupling reactions such as the Suzuki reaction and synthesis of polyhydroquinoline and 2,3-dihydroquinazoline-4-(1H)-one derivatives using a superparamagnetic palladium complex as catalyst have been developed. Graphical abstract: [Figure not available: see fulltext.].

Ni@diaza crown ether complex supported on magnetic nanoparticle was provided by grafting technique. The catalytic activity of Fe3O4@diaza crown ether@Ni was explored through one-pot synthesis of 2,3-dihydroquinazolin-4(1H)-ones and it was used as an efficient and recoverably constant nanocatalyst. FT-IR, SEM, TEM, XRD, BET, ICP, EDS, and TGA techniques were employed to specify the nanocatalyst. This heterogeneous catalyst demonstrated acceptable recyclability and could be used again several times with no considerable loss of its catalytic activity.

NiAl2O4 spinel nanocrystals were synthesized as mesoporous catalysts and were fully characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDS). These nanocrystals catalyzed the synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives via a one-pot, three-component condensation reaction of aromatic aldehydes, isatoic anhydride, and ammonium acetate or primary aromatic amine under microwave irradiation. By far, the most obvious advantages of the offered process are efficiency and recyclability of the catalyst as well as a significantly shorter reaction time.

2,3-Dihydroquinazolin-4(1H)-one derivatives have been synthesized via one-pot reaction of isatoic anhydride, aromatic aldehyde, and ammonium acetate catalyzed by FeCl3/neutral Al2O3 in tert-butanol under reflux conditions.

Immobilized sulfuric acid on magnetic Fe3O4 nanoparticles (Fe3O4 MNPs-OSO3H) as a new solid acid nanocomposite was successfully synthesized and its catalytic activity in a series of condensation reactions was studied. High catalytic activity, simple separation from reaction mixture by an external magnet and good reusability are several eco-friendly advantages of this catalytic system. It is noteworthy that this catalytic system is applicable to a wide range of spectrum of aromatic aldehydes, and the desired products were obtained in good to excellent yields under mild conditions. The use of ecofriendly solvents makes also this synthetic protocol ideal and fascinating from the environmental point of view.

An efficient and eco-friendly procedure for the synthesis of 2, 3-dihydroquinazolin-4(1H)- ones and spiroquinazolinones in the presence of sulfuric acid functionalized silica-coated magnetite nanoparticles under solvent-free conditions has been described. The reactions are completed in short times, and the products are obtained in high isolated yields without any undesirable side reaction. This method has several advantages, including short reaction time, facile operation, easy work-up, ecofriendly reaction conditions, high isolated yields, and reusability of the catalyst. The catalyst could be easily separated and recovered from the reaction mixture by an external magnet and reused in subsequent reactions with no considerable loss in activity.

In the present work, we report synthesis of anchored palladium complex on functionalized Fe3O4 nanoparticles via simple and inexpensive procedure. The final nanohybrid compound was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray Diffraction (XRD), thermal gravimetric analysis (TGA) and vibrating sample magnetometer (VSM) measurements. The catalytic activity of Fe3O4-Serine-Pd as an efficient and reusable catalyst was investigated for Suzuki and Stille reactions and synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives. The heterogeneous catalyst could be easily separated by applying a simple magnet and reused several consecutive runs without appreciable change in its catalytic activity.

A new magnetically separable nickel catalyst (Ni(NO3)2?Imine/Thiophene-Fe3O4@SiO2) was readily prepared and structurally characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), Vibrating sample magnetometer (VSM), X-Ray diffraction (XRD) and Atomic absorption spectroscopy (AAS). The Ni(NO3)2?Imine/Thiophene-Fe3O4@SiO2 exhibited efficient catalytic activity in the synthesis of 2,3-dihydroquinazoline-4(1H)-ones and polyhydroquinolines. Catalysis research under water and solvent-free conditions makes also this synthetic protocol ideal and fascinating from the environmental point of view. The catalyst can be magnetically recovered after the reaction and can be reused for many times without appreciable decrease in activity.

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We discovered that α-chymotrypsin has a promiscuous ability to catalyze the cyclocondensation of aromatic and aliphatic aldehydes with 2-aminobenzamides to afford the corresponding 2,3-dihydroquinazolin-4(1H)-ones successfully in high yields (90%–98%) under alcohol solvent. The catalytic activity of α-chymotrypsin was evaluated through investigating the temperature, the enzyme loading and the ratio of substrates in the enzyme-catalyzed reactions. The present method proves to be efficient and environmentally friendly in terms of short reaction time, high yield, green catalyst and the clean products obtained without further purification processes.

The 12-tungstophosphoric acid supported on silica gel (PW/SiO2) exhibits excellent activity in the synthesis of 2,3-dihydroquinazolin-4(1H)-ones by cyclocondensation reaction of 2-aminobenzamide with carbonyl compounds in water under reflux conditions. The desired products have been obtained in short reaction times in high yields. Our method has been successfully applied for both aldehydes and ketones (aromatic and aliphatic). Easy recovery and reusable catalyst, easy work-up and avoidance of using harmful organic solvents are the major advantages of our method in comparison to existing methods.

Bromine source immobilized on magnetic nanoparticles functionalized with diethylenetriamine was successfully synthesized and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometry, thermogravimetric analysis and X-ray diffraction. The catalytic activity in the synthesis of 2,3-dihydroquinazoline-4(1H)-one and polyhydroquinoline derivatives and in Knoevenagel condensation was studied. The bromine catalyst can be magnetically recovered and reused several times without significant loss of its catalytic activity. All products were obtained in high to excellent yields.

Abstract: Nano-Fe3O4/TiCl2/cellulose as a new, green, bio-based and recyclable catalyst was synthesized by bonding TiCl4 to hydroxyl groups of nano-cellulose and Fe3O4 nanoparticles. This catalyst was characterized by FT-IR, FESEM, TEM, XRF, BET, VSM, EDX and XRD. As a first report, the catalytic activity of nano-Fe3O4/TiCl2/cellulose was investigated in the synthesis of 2,3-dihydroquinazolin-4(1H)-ones in good to excellent yields under mild conditions. Graphical abstract: [Figure not available: see fulltext.]

Abstract: This article describes glycerol mediated eco-friendly approaches for the convenient access of structurally diverse 4,4′-(arylmethylene)bis(3-methyl-1H-pyrazol-5-ol) and 2-aryl-2,3-dihydroquinazolin-4(1H)-one motifs under catalyst-free conditions. Prominent advantages include clean processes, atom-efficiency, simplicity of the work-up, neutral conditions, low-cost reaction medium, excellent product yield and solvent reusability, in addition to relatively shorter reaction times. Graphical Abstract: [Figure not available: see fulltext.]

Tribenzylammonium tribromide supported onto magnetic nanoparticles (Br3-TBA-Fe3O4) as a bromine source was successfully synthesized and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry. The synthesized catalyst is shown to be a versatile and highly efficient heterogeneous catalyst for the Knoevenagel condensation and synthesis of 2,3-dihydroquinazolin-4(1H)-one and polyhydroquinoline derivatives. To the best of the authors' knowledge, this is the first report of the use of a bromine source immobilized on Fe3O4 nanoparticles as a magnetically separable catalyst for these reactions. The nanosolid catalyst can be magnetically recovered and reused readily several times without significant loss in catalytic efficiency.

Abstract: Diethylenetriamine immobilized on magnetic Fe3O4 nanoparticles (DETA-Fe3O4) was successfully prepared as a new and well dispersed magnetically separable amine catalyst. The structure of the resulting catalyst was well characterized by a series of analysis techniques such as FT-IR, SEM, EDX, VSM, TGA and XRD. The catalytic activity of DETA-Fe3O4 was evaluated with Knoevenagel condensation of active methylene compounds with aromatic aldehydes. Interestingly, the cyclocondensation of anthranilamide and aldehydes were effectively catalyzed by DETA-Fe3O4 in water, and the desired products (2,3-dihydroquinazoline-4(1H)-ones) were afforded in admirable yields. Catalysis research under aqueous medium (water) also makes this synthetic protocol ideal and fascinating from the environmental point of view. The amine catalyst can be magnetically recovered after the reaction and can be reused many times without appreciable decrease in activity.

A simple and straightforward synthesis of 2,3-dihydroquinazolin-4(1H)-ones is developed by reacting anthranilamide with various aldehydes or ketones under mild reaction conditions, using thiamine hydrochloride as a cost-effective, readily available, and green catalyst in water. Simple purification process, high yields within short reaction time, wide substrate scope, operational simplicity, and reusability of the catalyst up to three cycles enrich the applicability of the protocol.

An efficient and straightforward approach to the synthesis of 2,3-dihydroquinazolin-4(1H)-one from 2-aminobenzamide and carbonyl compounds (aldehydes and ketones) using biocompatible choline sulfate-based acidic ionic liquid as a cheap and readily available catalyst in water has been developed. Various 2,3-dihydroquinazolin-4(1H)-one have been prepared using low-cost and environmental friendly solvent and catalyst in good to excellent yields in a shorter reaction time. The choline sulfate catalyst was prepared using a simple method from readily available starting material and was confirmed by 1H NMR, FTIR, and TGA. The ease of the product separation without organic solvent and column chromatography and the reusability of the acidic ionic liquid catalyst makes this method economically affordable for large-scale synthesis.

The effect of different substituents on the kinetics of the reactions between 2-amino-benzamide and some of benzaldehyde derivatives have been spectrally investigated in the presence of formic acid. The proposed mechanism were challenged due to the determination of rate-determining step (RDS) and also, to obtain the general rate law of the reaction. For all substituents, the reactions followed the second-order kinetics and the partial orders of reactions were recognized with respect to each reactant. Electron withdrawing substituents on benzaldehyde ring increased the rate of reaction. Kinetic values (k and Ea) and associated activation parameters (ΔH?, ΔG? and ΔS?) of the reactions were determined. Both the Arrhenius and the Eyring equations were used to calculate activation energy. Comparison of magnitude of and T showed that the reactions were enthalpy controlled. Isokinetic plots for the reactions were plotted and linear relationship between and recognized that relative contribution of enthalpy and entropy to the overall free energy was the same in the reactions.

The invention discloses a method for synthesis of quinazolinone; the method comprises the steps of starting from o-aminobenzamide, taking water as a solvent, carrying out a ring-enlargement reaction with benzaldehyde, to generate a dihydroquinazolinone intermediate, and then under participation of a metal iridium complex, dehydrogenating to obtain the quinazolinone derivative; the reaction shows three remarkable advantages: 1) the reaction is carried out in an aqueous solution so as to reduce use of a large amount of organic solvents, and water is a cheap, green and safe solvent; 2) the reaction avoids use of highly toxic oxidants, so as to avoid damage to the environment; and 3) hydrogen gas generated from the reaction is a by-product, and has no environmental pollution; therefore, the reaction accords with the requirements of green chemistry, and has broad prospects for development.

The invention discloses a sulfonic acid ionic liquid catalyzing controlled synthesis method for dihydro-quinazolinone and quinazolinone derivatives. The dihydro-quinazolinone and quinazolinone derivatives are controllably prepared through a cascade reaction of anthranilamide or derivatives thereof and an aldehyde compound by taking sulfonic acid ionic liquid as a catalyst. Under the set catalytic reaction condition, the conversion rate of raw materials reaches up to 99%, and the yield of dihydro-quinazolinone and the yield of quinazolinone both can reach 95%. Compared with the prior art, the green solvent-ionic liquid is taken as the catalyst, no additional oxidizing agent or heavy metal catalyst is needed, the advantages that the reaction conditions are mild, environmental friendliness is achieved, the reaction selectivity and the product yield are high, controllable synthesis is achieved, and the catalyst can be recycled and reused conveniently are achieved, and the novel method is friendly to environment and efficient in synthesis.

An efficient synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives is accomplished in aqueous media by a three-component reaction of isatoic anhydride, primary amines or ammonium acetate, and aldehydes catalyzed by titanium silicon oxide nanopowder. A variety of 2,3-dihydroquinazolin-4(1H)-one derivatives were synthesized using this methodology in good to excellent yields. The catalyst was recovered and recycled up to four times without significant loss in the catalytic activity.

Abstract: An efficient, inexpensive and recyclable sulfated polyborate catalyst was applied in a three-component, one-pot cyclocondensation of isatoic anhydride, aldehydes and ammonium acetate/amines to afford the corresponding 2,3-dihydroquinazolin-4(1H)-ones. The key advantages of the present method are high yields, short reaction time, easy workup, recyclability of catalyst and ability to tolerate a variety of functional groups which gives economical as well as ecological rewards. Graphical Abstract: [Figure not available: see fulltext.].

1,4-Diazabicyclo[2.2.2]octane (DABCO) containing acidic poly(ionic liquid) (DAIL) has been prepared via condensation of 1,4-dichloro butane and DABCO, as an efficient acidic catalyst and has been applied in the one-pot preparation of 2,3-dihydroquinazolin

Graphene oxide (GO) nanosheet catalyzed new and straightforward strategies for the construction of 2,3-dihydroquinazolinones and quinazolin-4(3H)-ones starting from anthranilamide (2-aminobenzamide) and an aldehyde/ketone in aqueous medium at room temperature have been realized. This catalyst is also found to be efficient for the expedient construction of quinazolin-4(3H)-ones starting from anthranilamide and a β-ketoester/1,3-diketone following selective C-C bond cleavage of the β-ketoester/1,3-diketone at an elevated temperature under metal and oxidant free conditions.

The simple and high yield synthesis of H6Cu2[PPD]6[SiW9Cu3O37]·12H2O (PPD = p-phenylenediamine) as a new organic-inorganic hybrid polyoxometalate is reported. The new compound consists of trimetal-substitution polyoxometalate of A-β-SiW9Cu3O3710-, water molecules and coordinated and noncoordinated PPD molecules. H6Cu2[PPD]6[SiW9Cu3O37]·12H2O was firmly grafted on graphene oxide decorated with Fe3O4 nanoparticles. These nanocomposites were characterized by elemental analyses, thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), X-ray photoelectron spectrum (XPS), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and alternating gradient force magnetometer (AGFM). The results indicate that the size range of the nanoparticles are between 20 and 60 nm. The catalytic activity of H6Cu2[PPD]6[SiW9Cu3O37]·12H2O and the magnetically reusable nanocomposite of GO@Fe3O4@H6Cu2[PPD]6[SiW9Cu3O37]·12H2O were investigated in the Knoevenagel condensation and synthesis of 2,3-dihydroquinazolin-4(1H)-ones.

Self-assembly of phosphatidylcholine in water creates liposomal nanoreactors for environmentally friendly synthesis of hydroquinazolinones by two- or three-component reactions, without the use of an extra catalyst or solvent. Recycling of the reaction medium and the absence of a need for other organic reagents are further advantages of this protocol.

A facile, efficient, green, and environmentally benign method is described for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones by direct cyclocondensation of 2-aminobenzamide with aldehydes or ketones in water using PEG-SO3H as an acidic catalyst under room temperature. This new method totally avoids the use of organic acids, toxic or expensive solvents and affording the corresponding product in good to excellent yields in this reaction.

Abstract: In the present work, lactic acid was used as novel, green catalyst for synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives via two distinct methods, including reaction of 2-aminobenzamide with aldehydes/ketones or isatoic anhydride with ammonium acetate and aldehydes in neat condition at 70?°C. The desired products were obtained in satisfactory yields. Short reaction time, easy workup, and more importantly environmental benignity are the most outstanding advantages of these procedures. Graphical Abstract: [Figure not available: see fulltext.]

A simple, metal and ligand-free protocol for the synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives using choline hydroxide (ChOH) as an effective catalyst in an aqueous medium has been developed. The good to high yield of the desired product is obtained, with a low environmental factor and high atom economy. ChOH was found to be recyclable up to six consecutive runs without significant loss in its activity. The use of water as an environmentally benign solvent, ease of work up and efficient recyclability of the catalyst makes this process more advantageous and greener.

Abstract: A series of 2,3-dihydroquinazolin-4(1H)-ones have been synthesized with good to excellent yields by one-pot reaction using isatoic anhydride, aldehydes, and ammonium acetate or amines in acetonitrile in the presence of 4 ? molecular sieve modified with lanthanum(III) as an efficient heterogeneous catalyst. The catalyst could be reused without evident loss of activity. Graphical Abstract: [Figure not available: see fulltext.]

A series of 2-substituted quinazolin-4(1H)-ones have been synthesized in excellent yields and short reaction times by one-pot reaction of isatoic anhydride with ammonium acetate and aromatic aldehydes under microwave irradiation. The reaction was efficiently promoted by 0.5 mmol of 3,3′-(butane-1,4-diyl)bis(1,2-dimethyl-1H-imidazol-3-ium) dibromide [BDBIm] Br, and the catalyst could be recovered easily and reused without appreciable loss of reactivity.

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An efficient and eco-friendly method is reported for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones from the direct cyclocondensation of anthranilamide with aldehydes using p-sulfonic acid calix[4]arene (p-SAC) as a recyclable organocatalyst in excellent yields in water at room temperature. The catalyst was reusable without significant loss of catalytic efficiency. Operational simplicity, the compatibility with various functional groups, non-chromatographic purification technique, high yields and mild reaction conditions are the notable advantages of this procedure. Large scale reaction demonstrated the practical applicability of this methodology.

Abstract An efficient and green approach has been developed for the synthesis of 2-substituted 2,3-dihydroquinazolin-4(1H)-ones directly from corresponding substituted aromatic and aliphatic aldehyde and anthranilamide using recyclable polymer supported sulfonic acid catalyst under aqueous conditions. Environmental acceptability, operational simplicity, low cost, excellent functional group compatibility, and high yields are the important features of this protocol.