二氧化硅负载磷钨酸催化合成3,4-二氢嘧啶-2(1H)-酮衍生物

以取代苯甲醛、乙酰乙酸乙酯和尿素为原料,以溶胶凝胶法制备二氧化硅负载的磷钨酸（H3PW12O40/SiO2）为催化剂,催化合成3,4-二氢嘧啶-2(1H)-酮,考察了三组分摩尔比、反应温度、催化剂用量及反应时间对反应收率的影响。 研究表明,H3PW12O40/SiO2是合成3,4-二氢嘧啶-2(1H)-酮的良性催化剂,在取代苯甲醛的用量为0.04 mol,反应温度为90 ℃的条件下,收率可达73.1%~88.4%。 催化剂和产品结构分别经IR、XRD、SEM和1H NMR、IR、MS等技术手段表征。     

Supported N-propylsulfamic acid on magnetic nanoparticles used as recoverable and recyclable catalyst for the synthesis of 2, 3-dihydroquinazolin-4(1H)-ones in water

An efficient and eco-friendly method is reported for the synthesis of 2-substituted-2,3-dihydroquinazolin -4（1 H）-ones from direct cyclocondensation of anthranilamide with aldehydes and ketones using N-propylsulfamic acid supported onto magnetic Fe₃O₄ nanoparticles（MNPs-PSA） as a recoverable and recyclable nanocatalyst in good to excellent yields in water at 70℃.The catalyst was readily separated using an external magnet and reusable without significant loss of their catalytic efficiency.     

Base-mediated selective synthesis of diversely substituted N-heterocyclic enamines and enaminones by the hydroamination of alkynes

Regio- and stereoselective alkynylation of various N-heterocycles 1a-l using potassium and cesium salts in DMSO is described. Terminal alkynes 2a-k and internal alkynes 4a-f provided the kinetically stable Z-enamines 3a-l and 5a-i in good to excellent yields using KOH at 120 °C. Addition of heterocyclic amines to 1,3- and 1,4-diethynylbenzene 6a-b provided the mixture of E/Z isomers with KOH; however, with Cs(2)CO(3) selectively Z-isomers 7ab-db were obtained by the hydroamination at one triple bond. This developed methodology also provides an easy and novel access for the synthesis of enaminones 10a-c. The detailed work also supports the formation of cis-isomer by preferential addition of o-haloarylalkynes followed by intramolecular C2 arylation in the copper-catalyzed tandem synthesis of indolo and pyrrolo[2,1-a]isoquinolines.     

An environmentally benign,green, and efficient ionic liquid catalyzed synthesis of Quinoline derivatives via Knoevenagel condensation

The present investigation is in the interest of one-pot, environmentally friendly and efficient protocol for the synthesis of quinoline derivatives from 2-aminoarylketones and active methylene compounds in the presence of L-proline and ionic liquid 1,3-dimethylimidazolium methyl sulfate [MMIm][MSO₄]. The Ionic liquid which is used as a catalyst can be reused several times. The results obtained by using [MMIm][MSO₄] were also compared with those described in the literature. The advantages of the method are shorter reaction time, milder conditions, easy workup and better yields. The catalyst [MMIm][MSO₄] can be recovered for the subsequent reactions and reused without any appreciable loss of efficiency. This method of synthesis widens the applicability of Ionic liquids in heterocyclic compounds.     

Preparation of a novel,efficient, and recyclable magnetic catalyst,γ-Fe_2O_3@HAp-Ag nanoparticles,and a solvent- and halogen-free protocol for the synthesis of coumarin derivatives

In this protocol, Ag supported on the hydroxyapatite-core–shell magnetic γ-Fe_2O_3nanoparticles(γFe_2O_3@HAp-Ag NPs) as a novel, efficient, and magnetically recyclable catalyst is synthesized, and characterized by transmission electron microscopy(TEM), scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD), and vibrating sample magnetometry(VSM). The use of the catalyst is described in the synthesis of coumarin derivatives by the Pechmann condensation of various phenols with β-ketoesters under solvent- and halogen-free conditions at 80℃.This novel and inexpensive method offers advantages, such as recyclability simple experimental protocol, short reaction time, minimal work-up procedure, and excellent yields of products, together with desirable, eco-friendly, green aspects by avoiding toxic elements and solvents, and ease of recovery from the reaction mixture using an external magnet.     

Nano-copper chromite (nano-CuCr2O4): a novel and efficient catalyst for the synthesis of biscoumarin and pyrano[c]chromene derivatives in water at room temperature

Research on Chemical Intermediates - A clean, efficient and eco-friendly procedure has been developed using nano-copper chromite (nano-CuCr2O4) as catalyst for the synthesis of biscoumarin and...     

An efficient and green protocol for synthesis of novel [1,3]oxazino[5,6-c]quinolin-5-one derivatives using [Et3NH]HSO4 as a reusable catalyst

A simple, efficient, and eco-friendly procedure has been developed using acidic ionic liquid [Et₃NH]HSO₄ as catalyst for the synthesis of novel [1,3]oxazino[5,6-c]quinolin-5-one derivatives via one-pot three-component condensation reaction of 4-hydroxyquinolin-2(1H)-one, amine and formaldehyde in aqueous ethanol at room temperature. Mild and environmentally benign reaction conditions, short reaction time, good to excellent yields, nontoxic, cheap and easily available catalyst, reusability of catalyst and reaction media, and easy work-up are the key features of this method.     

Hybrid crystal NH3(CH2)4NH3SiF6 as an efficient catalyst for the synthesis of benzoxazoles,benzimidazoles and benzothiazoles under solvent-free conditions

An easy synthetic protocol for the synthesis of biologically active benzimidazole, benzothiazole and benzoxazole derivatives has been demonstrated using a hybrid crystal NH₃(CH₂)₄NH₃SiF₆ as a mild and efficient heterogeneous catalyst. Short reaction times, solvent-free conditions, good to excellent yields, easy reusability and use of an eco-friendly catalyst are some of the significant attributes of the present method.     

Sulfated polyborate catalyzed expeditious and efficient three-component synthesis of 3-methyl-4-(hetero)arylmethylene isoxazole-5(4H)-ones

A rapid and highly efficient methodology for the synthesis of 3-methyl-4-(hetero)arylmethylene isoxazole-5(4H)-ones has been developed using sulfated polyborate as a catalyst. The multicomponent reaction of an aromatic/heterocyclic aldehyde, hydroxylamine hydrochloride, and ethyl acetoacetate under a solvent free condition at 80 °C is described. This protocol has promising features for the reaction response such as shorter reaction time, easy work-up, ease of separation of pure product with high yields and simplicity in the experimental procedure. The products have been obtained in high yields (80–90%) and convenient reaction time (15–30 min). The method is operationally simple and eco-friendly.     

One-pot three-component green synthesis of novel dihydrophthalazine-1,4-diones

Green and efficient one-pot three-component synthesis of novel 2-(7-amino-2,2-dimethyl-4-oxo-5-phenyl-4,5-dihydropyrano[2,3-d][1,3]dioxin-6-ylcarbonyl)-2,3-dihydrophthalazine-1,4-diones have been developed by condensing 3-(1,4-dioxo-1,2,3,4-tetrahydrophthalazin-2-yl)-3-oxopropanenitrile with benzaldehydes and Meldrum’s acid using L-proline as catalyst in ethanol at room temperature. The products have been isolated as pure compounds in good yields without using column chromatography.     

An environmentally friendly,chemoselective, and efficient protocol for the preparation of coumarin derivatives by Pechman condensation reaction using new and reusable heterogeneous Lewis acid catalyst polystyrene-supported GaCl3

An environmentally benign Pechman protocol for the one-pot synthesis of 4-substituted coumarins through the condensation reactions of phenol substrates with β-ketoesters using polystyrene-supported GaCl₃ (PS–GaCl₃) as a highly active and reusable solid Lewis acid catalyst under mild and heterogeneous conditions in good to excellent yields is described. This new protocol is easy, simple, cost-effective, chemoselective, and in addition has the advantages of easy availability, stability, reusability and eco-friendly character of the catalyst, high to excellent yields, simple experimental and work-up procedure.     

Eco-friendly development: synthesis of 3-(2-chloroquinolin-3-yl)-1-aryl prop-2-en-1-one using K2CO3–Al2O3 under ultrasonic radiations

Abstract

K₂CO₃–Al₂O₃ has been used as an efficient, eco-friendly, and cost-effective activating catalyst for the synthesis of 3-(2-chloroquinolin-3-yl)-1-substituted phenyl prop-2-en-1-ones starting from 2-chloroquinoline-3-carbaldehyde and acetophenone. The reactions were performed under ultrasound irradiations. A substantial enhancing effect in the yield was observed when the catalyst was activated under ultrasonic waves. The K₂CO₃–Al₂O₃ catalyst can compete with the traditional NaOH/MeOH system of catalysis when the reaction is carried out under ultrasound. Herein, a benign, eco-friendly, efficient, and extremely fast procedure for the synthesis of quinoline chalcones has been demonstrated successfully.     

微波辐射下FeCl3•6H2O催化绿色合成3,4-二氢嘧啶-2-酮

在微波辐射下, 仅以六水合三氯化铁为催化剂, 将芳香醛、β-二羰基化合物和脲(物质的量比为1∶1.5∶1.5)在无水乙醇中回流, 高效地合成了3,4-二氢嘧啶-2-酮, 反应时间4～6 min, 操作简便, 环境友好.     

An expeditious and greener one-pot synthesis of 4H-chromenes catalyzed by Ba(OTf)2 in PEG-water

Abstract

An expeditious synthesis of 4H-chromenes has been achieved by three-component one-pot condensation of 1,3-diketone, aldehyde, and malononitrile using Ba(OTf)₂ as catalyst in PEG-water at room temperature. Results from various reaction media and different metal triflates as catalysts show that choice of proper catalyst and the solvent system play a key role in the synthesis of 4H-chromene-3-carbonitrile derivatives. The catalyst can be recovered and reused at least five times without loss of activity. The application of an eco-friendly, noncorrosive, and reusable catalytic system with high isolated yield of the products makes this method advantageous.     

New applications of phosphoric acid supported on alumina (H3PO4–Al2O3) as a reusable heterogeneous catalyst for preparation of 2,3-dihydroquinazoline-4(1H)-ones, 2H-indazolo[2,1-b]phthalazinetriones,and benzo[4,5]imidazo[1,2-a]pyrimidines

An eco-friendly procedure for synthesis of 2,3-dihydroquinazoline-4(1H)-one, 2H-indazolo[2,1-b]phthalazinetrione, and benzo[4,5]imidazo[1,2-a]pyrimidine derivatives by three-component reaction, with phosphoric acid supported on alumina as catalyst, is described. Noticeable features of the method are that it is solvent-free, work-up is easy, yields are excellent, and the catalyst is reusable.     

Catalytic activity of TiO2 nanoparticles in the synthesis of some 2,3-disubstituted dihydroquinazolin-4（1H）-ones

Green chemistry is playing an important role for synthesizing organic compounds, due to its eco-friendly nature and low cost. In green chemistry, metal nanoparticles exhibited some useful physical and chemical properties （catalytic activity）. Due to its diverse properties, nanoparticles can be utilized as a catalyst in various organic reactions. Recent research has been directed towards the utilization of eco- friendly and bio-friendly plant materials in nanoparticles synthesis. In our present work, TiO2 nanoparticles （TiO2 NPs） were synthesized using Annona squamosa peel extract and their catalytic applications were studied on the 2,3-disubstituted dihydroquinazolin-4（l1H）-one synthesis. Synthesized compounds were confirmed using FT-IR.1H NMR, 13C NMR and GC-MS analyses.     

One-pot synthesis of dihydropyrimidones using silica-supported heteropoly acid as an efficient and reusable catalyst: Improved protocol conditions for the Biginelli reaction

An efficient synthesis of 3,4-dihydropyrimidinones or thiones (DHPMs) is described, using silica-supported heteropoly acid H₃PW₁₂O₄₀/SiO₂ (PW/SiO₂) for the first time as the catalyst from an aldehyde, β-keto ester and urea or thiourea in acetonitrile. Compared to the classical Biginelli reaction conditions, this method consistently has the advantage of excellent yields, mild reaction conditions, ease of workup, survival of different functional groups, and short reaction times.     

Greener and facile aqueous regioselective synthesis of vicinal azidoalcohols using silica-bound 3-((polyethyleneglycol)ethyl)-8-methyl-1H-imidazol-3-ium bromide as a recyclable catalyst

An environmentally benign, aqueous synthesis of vicinal azidoalcohols by the regioselective nucleophilic ring opening of epoxides with azide anion using silica-bound 3-((polyethyleneglycol)ethyl)-8-methyl-1H-imidazol-3-ium bromide as an effective heterogeneous phase transfer catalyst is described. Short reaction time, simple work-up procedure, high yield, reusability, and use of an eco-friendly catalyst are some of the striking features of the present protocol.     

One-step solvent-free synthesis of fluoroalkyl-substituted 4-hydroxy-2-oxo(thioxo)hexahydropyrimidines in the presence of 1-butyl-3-methylimidazolium tetrafluoroborate

A convenient procedure has been developed for the synthesis of fluoroalkyl-substituted 6-aryl-4-hydroxy-2-oxo-(thioxo)hexahydropyrimidine derivatives by three-component condensation of fluorinated β-dicarbonyl compounds with aromatic aldehydes and urea or thiourea in the absence of a solvent using 6 mol % of 1-butyl-3-methylimidazolium tetrafluoroborate as catalyst.     

An expedient, fast and competent synthesis of organic dithiocarbamates over nanocrystalline MgO in water at room temperature

A new, expeditious, efficient and eco-friendly method for the synthesis of organic dithiocarbamates has been achieved at room temperature using basic nanocrystalline MgO catalyst in aqueous condition. The method has been applied for the synthesis of a range of compounds with variable functionalities in excellent yield and selectivity.