299949-24-9

An efficient and heterogeneous novel magnetic silica-coated picolylaminecopper complex [Fe3O4@SiO2@GP/Picolylamine-Cu(II)] was synthesized, characterized, and employed as a magnetically recoverable nanocatalyst in Biginelli condensation for the preparatio

An environmentally benign three-component Biginelli protocol for the one-pot synthesis of substituted 3,4-dihydropyrimidin-2(1H)-ones/thiones using an accessible, nontoxic, easy to handle, and recoverable macromolecular Lewis acidic catalyst is developed.

A quinoline-linked and ionic liquid-decorated covalent organic framework was prepared by incorporation of a multicomponent Povarov reaction and postsynthetic modification. The imidazolium and sulfonic acid-decorated COF-IM-SO3H can be a highly efficient B

Water was magnetized via an external magnetic field and employed, for the first time, as a solvent in green preparation of 3,4-dihydropyrimidin-2(1H)-ones by the one-pot three-component condensation reaction using boric acid as a catalyst. Shorter reactio

In this study, simple and effective methods were used for the preparation of an ionic liquid that immobilized magnetite nanoparticles. Fe3O4nanoparticles were preparedviaa chemical co-precipitation method. Then, a SiO2shel

The invention discloses a synthesis method of a dihydropyrimidone compound, which belongs to the technical field of organic synthesis, and comprises the following steps: by taking benzaldehyde or a derivative thereof, ethyl acetoacetate or acetylacetone a

Materials with high specific surface area and bearing abundant basic sites at their pore surface are very demanding as heterogeneous catalyst for the eco-friendly base catalyzed reactions. Here we have developed a new secondary amine linked triazine and p

Natural dolomitic limestone (NDL) is employed as a heterogeneous green catalyst for the synthesis of medicinally valuable benzimidazoles, dihydropyrimidinones, and highly functionalized pyridines via C–N, C–C, and C–S bond formations in a mixture of ethan

A well-known Biginelli reaction for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones was performed in an environmentally responsible manner. Large numbers of substrates were screened, and found to give excellent yields of the desired products. In

Biginelli reaction entails acid-catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) with simply-accessible initial substances, specifically, aldehyde, urea, and active methylene compound. DHPMs have stimulated a resurgence of attention in the previous two decades because of their broad-ranging pharmacological actions and the existence of varied all-natural products. Currently, green methods to asymmetric Biginelli reaction have been researched for anti-inflammatory DHPMs. In materials chemistry, DHPMs are increasingly decision applications in the creation of materials like polymers, adhesives, fabric dyes, etc. In light of the simplicity by which the Biginelli reaction is conducted, numerous interesting prospects expect its exploitation in variety fields. CoFe2O4?SiO2-NH2-CoII is herein turned out to be an effective catalyst at a three-component Biginelli reaction. The yield of the corresponding DHPMs was rather large (20 cases; average 92 percent). Finally, we herein suggest a procedure that shows lots of advantages and benefits such as the whole lack of solvents, mild reaction conditions, comparatively short reaction times. Also, CoFe2O4?SiO2-NH2-CoII NPs catalyst has been readily recovered from the reaction combination and reused, without the decrease of catalytic action.

4,6-O-Ethylidene-N-(2-hydroxybenzylidene)-β-D-glucopyranosylamine has been reacted with ytterbium(III) acetate and the resultant complex has been used as catalyst in the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones (DHPMs). Twenty-one DHPMs have been synthesised under neat reaction condition in appreciable yields (73–96percent) and reusability of the catalyst has been established.

Heterocyclic compounds with biological and pharmacological activates like 3,4-dihydropyrimidin-2-(1H)-ones and 1,4-dihydropyridines have attracted great interest. Boehmite nanoparticles functionalized with silylpropyl sulfamic acid (BNPs?SiO2(C

A one-pot efficient biocatalytic strategy for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones was developed in a circulating microwave reactor selecting α-chymotrypsin as the promiscuous biocatalyst. In the circulating reaction system, the combination o

The aim of this research was to develop a procedure for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones under environmentally friendly conditions using alcohols as the starting materials in aqueous media. The developed protocol resulted in 3,4-dihydropyrimidin-2(1H)-ones derivatives, which are relevant intermediates with therapeutic and pharmacological properties. Target products were synthetized in a tandem process, which meets the requirements of pharmaceutical chemistry. The influence of the reaction conditions was investigated, and as a result, various substituted 3,4-dihydropyrimidin-2(1H)-ones were obtained with a yield of up to 81percent, free from heavy metal impurities.

A new magnetic metal–organic framework nanocomposite (CoFe2O4/TMU-17-NH2) was prepared via an embedding approach by synthesis of the metal–organic framework crystals in the presence of magnetic cobalt ferrite nanoparticles. We demonstrated that the resulting magnetic nanocomposite can serve as a recyclable nanocatalyst for one-pot synthesis of bis-3,4-dihydropyrimidin-2(1H)-one and 3,4-dihydropyrimidin-2(1H)-one derivatives via three-component reaction of 1,3-diketone, urea or thiourea and aromatic aldehyde under solvent-free conditions. CoFe2O4/TMU-17-NH2 was characterized using various techniques. The recovery of the nanocomposite was achieved by a simple magnetic decantation and it was reused at least seven times without significant degradation in catalytic activity.

In our studies on the catalytic activity of Group IVB transition metal Lewis acids, Hf(OTf)4 was identified as a highly potent catalyst for”one-pot, three-component” Biginelli reaction. More importantly, it was found that solvent-free conditions, in contrast to solvent-based conditions, could dramatically promote the Hf(OTf)4-catalyzed formation of 3,4-dihydro-pyrimidin-2-(1H)-ones. To provide a mechanistic explanation, we closely examined the catalytic effects of Hf(OTf)4 on all three potential reaction pathways in both “sequential bimolecular condensations” and “one-pot, three-component” manners. The experimental results showed that the synergistic effects of solvent-free conditions and Hf(OTf)4 catalysis not only drastically accelerate Biginelli reaction by enhancing the imine route and activating the enamine route but also avoid the formation of Knoevenagel adduct, which may lead to an undesired byproduct. In addition, 1H-MMR tracing of the H-D exchange reaction of methyl acetoacetate in MeOH-d4 indicated that Hf(IV) cation may significantly accelerate ketone-enol tautomerization and activate the β-ketone moiety, thereby contributing to the overall reaction rate.

A unique 3D framework containing three different types of nanoscale polyhedron cages was constructed by incorporating dinuclear [M2(μ2-OH)(COO)4] (M = Co, Ni) secondary building units and pyridyl-carboxylic-acid-supported tetracarboxylates. The assembled complexes possess isolated bifunctional single-site Lewis acid and Br?nsted acid and can be used as highly efficient heterogeneous catalysts for the solvent-free Biginelli reaction with a high turnover frequency value of 338.4 h-1. Interestingly, a variety of 3,4-dihydropyrimidin-2(1H)-ones have been obtained in high yields and short times.

This paper deals with the study of mechanism of the Biginelli reaction using low melting mixture as solvent and catalyst. The catalytic effect of low melting mixture and the reaction mechanism is discussed on the basis of nuclear magnetic resonance (NMR)

Catalytic synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones was efficiently promoted by as little as 2.5?mol% of Br?nsted acidic ionic liquid [(CH2)3SO3HMIM]HSO4 catalyst loading via rapid heating ways. Inter

We investigated a novel catalytic application of nickel-doped zinc oxide (Ni-ZnO) nanoparticles and zinc oxide (ZnO) nanoflakes at room temperature in an aqueous hydrotropic solution for the synthesis of biologically active dihydropyrimidones (DHPMs). Ni-

A series of MCM-41 supported functionalized ionic liquids doped with copper species were prepared, characterized and evaluated as catalysts in the Biginelli reaction. Most of these supported ionic liquids perform well in the reaction, especially the multifunctional copper coordinated MCM-41 supported heterogeneous catalysts (0.5)IL-TiCl5@MCM-41@Cu(15) and (0.5)IL-HSO4@MCM-41@Cu(15). The catalytic tests revealed that (0.5)IL-HSO4@MCM-41@Cu(15) was the best and powerful catalyst in the Biginelli reaction for the preparation of 3,4-dihydropyrimidinones with high to excellent yields. The catalyst can be easily separated from the reaction mixture by filtration and reused in six consecutive cycles without significant loss in catalytic activity.

Cu(II) immobilized on mesoporous organosilica nanoparticles (Cu2+@MSNs-(CO2 ?)2) has been synthesized, as a inorganic–organic nanohybrid catalyst, through a post-grafting approach. Its characterization is carrie

Background: Biginelli reaction is one of the most important multiple-component chemical reactions which creates 3,4-dihydropyrimidin-2(1H)-ones. Even though Biginelli reaction was reported over a century using different substrates, literature lacks the ex

A highly efficient and facile procedure for the one-pot three-component synthesis of 3,4-dihydropyrimidin-2-(1H)ones/thiones from the one-pot condensation of aldehyde, β-dicarbonyl compound and urea/thiourea was developed. The methodology is applicable to

Abstract: Nanometasilica disulfuric acid (NMSDSA) and nanometasilica monosulfuric acid sodium salt (NMSMSA) as two nanostructured novel, green and heterogeneous catalysts were designed, synthesized and fully characterized by FT-IR, energy-dispersive X-ray spectroscopy, X-ray diffraction patterns, scanning electron microscopy, transmission electron microscopy and thermal gravimetric analysis. Then their catalytic applications were studied in the Biginelli-type reaction for the synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives via one-pot three-component condensation reaction between several aldehydes, ethyl acetoacetate and urea or thiourea. To further study catalytic properties of NMSDSA and NMSMSA, they were used in the synthesis of polyhydroquinoline and 2,3-dihydroquinazolin-4(1H)-one derivatives under same reaction conditions. NMSDSA and NMSMSA have advantages such as cost-effectiveness, cleaner reaction profile, benign and heterogeneous characters, reusability of the catalysts and being in agreement with the green chemistry protocols. The described nanostructured catalysts have natural-based acids and potential for industrial production. Graphical Abstract: Synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives via Biginelli-type reaction, polyhydroquinolines and 2,3-dihydroquinazolin-4(1H)-ones using NMSDSA and NMSMSA as two novel nanostructured catalysts. [Figure not available: see fulltext.]

A novel and green approach was adopted for the synthesis of 3,4-dihydropyrimidin-2(1H)-one/thiones derivatives using Punica granatum peel as an inexpensive, efficient and mild catalyst under solvent-free condition. The methodology is characterized by high

An efficient one-pot synthesis of pyrimidin-2(1H)-ones via three-component condensation of aldehyde, ethyl acetoacetate and urea using 1,4-bis(triphenylphosphonium)-2-butene peroxodisulfate [BTPBPDS] as an oxidant is described.

Abstract: A novel highly efficient magnetically retrievable catalyst was developed by the immobilization of H3PW12O40 (20–60 wt%) on the surface of zirconia-encapsulated Fe3O4 nanoparticles. The prepared HPW supported on nano-Fe3O4@ZrO2 heterogeneous acid catalyst (or n-Fe3O4@ZrO2/HPW) was fully characterized by several physicochemical techniques such as: Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, vibrating sample magnetometry and thermogravimetric analysis. The FT-IR spectroscopic data revealed that H3PW12O40 molecules on the nano-Fe3O4@ZrO2 support existed in the Keggin structure. The acidity of the catalyst was measured by the help of a potentiometric titration with n-butylamine. It was surprising that this very strong solid acid catalyst exhibited an excellent acid strength which was as a result of possessing a higher number of surface active sites compared to its homogeneous analogues. The catalytic activity of the as-prepared novel nano-Fe3O4@ZrO2/HPW was explored through the one-pot three-component synthesis of different 3,4-dihydropyrimidin-2(1H)-ones (i.e. Biginelli reaction) and 1,4-dihydropyridines (i.e. Hantzsh reaction) under solvent free condition. The sample of 40 wt% showed higher acidity and activity in the catalytic transformation. After the reaction, the catalyst/product isolation could be easily achieved with an external magnetic field and the catalyst could be easily recycled for at least five times without any decrease in its high catalytic activity. The excellent recyclability was attributed to the strong interaction between the hydroxyl groups of the nano-Fe3O4@ZrO2 support and the HPW species. Graphical Abstract: [Figure not available: see fulltext.].

A novel polyethylene-supported Fe/ionic liquid complex (PEt@Fe/IL) is prepared, characterized and its catalytic performance is investigated in the synthesis of 3,4-dihydropyrimidinones. The chemical properties and thermal stability of the PEt@Fe/IL materi

Abstract: Sulfated graphene and graphene oxide were used successfully as the heterogeneous catalysts for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones (-thiones) through the reaction between ethyl acetoacetate, an aldehyde, and an urea or thiourea, at

In the present study, we report a simple, facile and efficient solvent-free protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones by the three component condensation of aldehyde, ethyl acetoacetate and urea through using Co@imine-Na+-MM

Sulfonic acid-functionalized titanomagnetite (Fe3?xTixO4@SO3H) nanoparticles were prepared by grafting sulfonic acid groups on Fe3?xTixO4 nanoparticles. This new heterogeneous ac

An efficient synthesis of novel 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) and their derivatives, using Br?nsted acidic ionic liquid [C2 O2 BBTA][TFA] as a catalyst, from the condensation of aryl aldehyde, β-ketoester and urea was described. Reactions procee

A simple, facile and efficient synthesis of functionalized dihydropyrimidinones and polyhydroquinolines using molybdenum(vi) dichloride dioxide (MoO2Cl2) has been developed. The present protocol demonstrates the exceptional tolerance

The stability and basicity origin of some common urea based deep eutectic mixtures/solvents (DES) were studied. We have observed an unexpected Hantzsch dihydropyridine reaction in sorbitol/urea DES, where the source of ammonia was found not to be originated from the individual ingredients of the DES. Our results showed that decomposition of urea occurs in DES at lower than expected temperatures, namely below 100 °C and is enhanced in diol DES by the formation of carbonates causing their unexplained basicity. Carbohydrates and choline chloride (ChCl) DES exhibit lower rates of decomposition, while no decomposition was observed from neat urea or MeOH and EtOH urea solutions.

1,3-Disulfonic acid benzimidazolium chloride ionic liquid ([Dsbim]Cl) was prepared, characterized and applied as an efficient, homogeneous and recyclable catalyst for the synthesis of 3,4-dihydropyrimidine-2-(1H)-ones/thiones through the one-pot three-com

A facile, high yielding, and simple method for the synthesis of a library of dihydropyrimidinones (and -thiones) via the one-pot Biginelli reaction of aldehydes is reported. The method employs the Br?nsted acidic IL [bmim(SO3H][OTf] or Zn(NTfs

A series of pyrimidinone derivatives were efficiently synthesized using PEG-SANM nanocomposite as the solid acid nanocatalyst under mild and solvent-free conditions. The generality of the process was successfully demonstrated by variation of the starting

A novel iron-containing Schiff base and ionic liquid based bifunctional periodic mesoporous organosilica (Fe@SBIL-BPMO) was prepared, characterized, and its catalytic application was developed. The SBIL-BPMO was first prepared by the grafting of 3-aminopr

An efficient and green route for the synthesis of dihydropyrimidinones via microwave-assisted Biginelli reaction catalyzed by 3 mol% of heteropolyanion-based ionic liquids under solvent-free conditions has been reported. The practical reaction was found t

Tris(pentafluorophenyl)borane catalyzed, one-pot, simple, efficient and environmentally benign protocol for the synthesis of dihydropyrimidinones/thiones via Biginelli reaction has been described. The main highlights of the present protocol is low catalys

Zirconocene bis(perfluorobutanesulfonate) is air- and water-stable and proved to be ionic on basis of conductivity measurements. It exhibits high catalytic efficiency for the synthesis of N-heterocyclic compounds under solvent-free condition, such as benzimidazoles, benzodiazepines, dihydropyrimidinones and dihydropyridines under mild condition. Furthermore, it can be reused without loss of activity in a test of five cycles. This catalytic system affords a simple and efficient approach for the synthesis of N-heterocyclic compounds.

β-Cyclodextrin-propyl sulfonic acid (β-CD-PSA) is reported as a new and eco-friendly catalyst for the synthesis of 3,4-dihydropyrimidinones from one-pot multi-component reaction of aromatic aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under so

A simple and effective synthesis of 3,4-dihydropyrimidin-2(1H)-one and thione derivatives has been developed in the presence of nano cobalt manganese oxide as catalyst under thermal solvent-free conditions. The proposed procedure ensures easy to handle, r

Abstract Phthalimide-N-sulfonic acid (PISA) was straightforwardly synthesized via addition of chlorosulfonic acid to a solution of potassium phthalimide in dry dichloromethane. This reagent is found to be an efficient solid acidic catalyst in the Biginell

The usage of potassium phthalimide (PPI) for the simple and green one-step multicomponent synthesis of Hantzsch 1,4-dihydropyridines, polyhydroquinolines, 3,4-dihydropyrimidin-2(1H)-ones/thiones, and octahydroquinazolinones under solventless conditions at 120°C is reported. The method is operationally simple, environmentally benign, and has relatively high yields. The other merits of this method include efficient, clean, green, and catalyst reusability.

Simple and highly efficient approach for the synthesis of γ-Benzopyranones and 3,4-Dihydropyrimidin-2(1H)-ones/thiones using ammonium acetate as a promoter under thermal as well as microwave irradiation using solvent-free conditions has been demonstrated.

An extremely efficient heterogeneous protocol is reported for the one-pot, three-component synthesis of a series of dihydropyrimidinones (DHPMs) in the presence of ZnO nanoparticles in water as a green solvent. The ZnO nanoparticles exhibited excellent ca

We report here an understanding of systems chemistry on small molecules through covalent mechanochemistry. As a proof-of-concept, the multicomponent Biginelli reaction by subcomponent synthesis was considered as a model system. Reactions were performed un

The catalytic application of a novel manganese-containing periodic mesoporous organosilica with ionic-liquid framework (Mn@PMO-IL) in the Biginelli reaction was investigated. First, the Mn@PMO-IL nanocatalyst was prepared and characterized by TEM, SEM, X-