Reaction Of Ethyl Research Articles

ZnO@SnO2 Mixed Metal Oxide as an Efficient and Recoverable Nanocatalyst for the Solvent Free Synthesis of Hantzsch 1,4-Dihydropyridines

An efficient synthesis of Hantzsch 1,4-dihydropyridines via a one-pot three-component reaction of ethyl acetoacetate, substituted aldehydes and ammonium acetate in the presence of ZnO@SnO2 mixed metal oxide nanoparticles under solvent-free conditions has been reported. Compare to the reported reactions, this method shows attractive aspects such as cleaner reaction profile, shorter reaction times, minimum catalyst loading and high yields. Isolated catalysts were reused for new reactions without considerable loss of their catalytic activity.

Synthesis of novel polycarbonyl Schiff bases by ring-opening reaction of ethyl 5-acyl-4-pyrone-2-carboxylates with primary mono- and diamines.

An approach for the introduction of the tricarbonyl moiety into aromatic, heterocyclic, and aliphatic amines with the use of acylpyrones has been developed for the synthesis and the design of novel polycarbonyl Schiff base ligands, including salphen structures. This Michael addition–ring-opening reaction proceeds under mild conditions (stirring at 0–20 °C) via the attack at the C-6 position of the pyrone ring in good to high yields (up to 99%) with excellent selectivity. The products can be easily isolated by crystallization without the use of chromatography. The scope of the reaction, tautomeric equilibrium of open-chain products, and their cyclization into pyridone structures were investigated.

Synthesis and Cytotoxic Activity of Some Novel Thieno[2,3-d:4,5-d’]Dipyrimidine Derivatives

Synthesis of some novel tricyclic compounds bearing thienodipyrimidine moiety by the reaction of ethyl 6-amino-1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydrothieno[3,2-d]pyrimidine-7-carboxylate (1) with different types of aromatic amines to give the corresponding carboxamide derivatives 2-11, which cyclized with triethyl orthoformate in acetic anhydride to afford thieno[2,3-d:4,5-d']dipyrimidine derivatives 12-15 is described. Similarly, thieno[2,3-d:4,5-d']dipyrimidine derivative 17 was also prepared via the reaction of carboxamide derivative 2 with chloroacetyl chloride in chloroform to give thieno[3,2-d]pyrimidine-7-carboxamide derivative 16, followed by a cyclization in boiling acetic anhydride. The structure of these compounds was confirmed on the basis of their spectral and analytical data such as IR, 1H-NMR, 13C-NMR spectroscopy and mass spectral data. The synthesized compounds were screened for their cytotoxic activity.

Pyridine‐2(1H)‐thiones: Versatile Precursors for Novel Pyrazolo[3,4‐b]pyridine, Thieno[2,3‐b]pyridines, and Their Fused Azines

Pyridine‐2(1H)‐thiones were prepared and reacted with several active halogenated reagents to afford novel thieno[2,3‐b]pyridines in excellent yields. Thieno[2,3‐b]pyridine‐2‐carbohydrazide derivative was prepared by the reaction of either ethyl 2‐((3‐cyanopyridin‐2‐yl)thio)acetate derivative or thieno[2,3‐b]pyridine‐2‐carboxylate derivative with hydrazine hydrate. On the other hand, the reaction of either pyridine‐2(1H)‐thione or ethyl 2‐((pyridin‐2‐yl)thio)acetate derivative with hydrazine hydrate afforded the corresponding 1H‐pyrazolo[3,4‐b]pyridine derivative. Thieno[2,3‐b]pyridine derivatives reacted with several reagents to afford the corresponding pyrimidine‐4(3H)‐ones and [1,2,3]triazin‐4‐(3H)‐one. Moreover, 2‐carbohydrazide derivative reacted with β‐dicarbonyl reagents to give 2‐((3‐methyl‐1H‐pyrazol‐1‐yl)carbonyl)thienopyridines. The structure of the target molecules is elucidated using elemental analyses and spectral data.

Synthesis of spiro[cyclopent-2/3-ene-1,2′-[1,3]thiazolo[3,2-a] pyrimidine] derivatives via 1,3-dipolar cycloaddition reaction of ethyl buta-2,3-dienoate

The 1,3-dipolar cycloaddition reaction of ethyl (2Z)-5-aryl-2-(2-methoxy-2-oxoethylidene)-7-methyl-2,3-dihydro-5H-thiazolo[3,2-a] pyrimidine-6-carboxylate and ethyl buta-2,3-dienoate catalysed by triphenylphosphine afforded novel spiro[cyclopent-2-ene-1,2′-[1,3] thiazolo[3,2-a]pyrimidine] and spiro[cyclopent-3-ene-1,2′-[1,3]thiazolo[3,2-a]pyrimidine] derivatives in moderate yields. The structures of all the products were characterised thoroughly by NMR, IR and HRMS together with X-ray crystallographic analysis.

An Unprecedented Organocascade Synthesis of Functionalized Bicyclic Nitrones from 2‐Aminomalonate Derived Nucleophiles and 1‐Nitro‐1,3‐Enynes via Allenes Formation and Subsequent Rearrangement

AbstractAn efficient organocatalytic cascade reaction for synthesising functionalized bicyclic nitrones is reported. The reaction of dielectrophilic ethyl 2‐(nitromethylene)‐4‐arylbut‐3‐ynoate and (E)‐diethyl 2‐((2‐hydroxybenzylidene)‐amino)malonates to give a unique nitrone scaffold in the presence of a catalytic amount of DABCO is described. The working mechanism was proposed to proceed with allene formation followed by intramolecular cyclization and the rearrangement of an oxygen atom in the nitro group. A broad range of substrates was accessed in this facile chemical transformation, in which the bicyclic nitrones were isolated in moderate to good yields (19% to 79%) with excellent diastereoselectivity (>20:1 dr).magnified image

Acidic ionic liquids: highly efficient catalysts for one-pot four-component synthesis of pyrazolo[1,2-b]phthalazines under solvent-free conditions

A series of novel pyrazolo[1,2- b ]phthalazine-2-carboxylate derivatives has been synthesized via one-pot four-component reaction of aromatic aldehyde, ethyl or methyl acetoacetate, hydrazine hydrate, and phthalic anhydride in the presence of acidic ionic liquids such as 3-methyl-1-sulfo-1 H -imidazol-3-ium chloride, 1,3-disulfo-1 H -imidazol-3-ium chloride, and triethyl(sulfo)ammonium chloride as the catalyst. This method involves particular advantages such as environmentally benign catalysts, high yields of product, reusability of ionic liquids with high activity, short reaction times, no hazardous solvent, and easy workup.

An unusual synthesis of 3-(2-(arylamino)thiazol-4-yl)-2H-chromen-2-ones from ethyl 2-(chloromethyl)-2-hydroxy-2H-chromene-3-carboxylate via benzopyran ring opening.

An unusual and unexpected synthesis of 3-(2-(arylamino)thiazol-4-yl)-2H-chromen-2-ones has been observed by the reaction of ethyl 2-(chloromethyl)-2-hydroxy-2H-chromene-3-carboxylate with various arylthioureas in ethanol under mild reaction conditions with excellent yields. The ambiguity in the structure of the obtained products has been solved by recording its single-crystal X-ray analysis. This protocol has been found to be a novel approach for the preparation of title compounds via benzopyran ring opening. A systematic plausible mechanism has been proposed for the formation of the product. Also, an efficient one-pot three-component method has been demonstrated for the formation of title compounds starting from salicylaldehyde.

Synthesis of Dispiro[Indeno[1,2-b]Quinoxaline-11,3′-Pyrrolizine-2′,2″-[1,3] Thiazolo[3,2-a]Pyrimidine Via Cycloaddition Reactions

The 1,3-dipolar cycloaddition reaction of ethyl 5-aryl-2-(2-methoxy-2-oxoethylidene)-7-methyl-3-oxo-2,3-dihydro-5 H-[1,3]thiazolo[3,2- a] pyrimidine-6-carboxylate and azomethine ylide, which was generated in situ by the reaction of 11 H-indeno[1,2- b]quinoxalin-11-one and L-proline, afforded novel 6″ethyl 1′-methyl 5″aryl-7″methyl-3″oxo-5’,6’,7’,7a′-tetrahydro-1' H,3″ H,5″ H-dispiro[indeno[1,2- b]quinoxaline-11, 3 ‘-pyrrolizine-2’,2″-[1,3]thiazolo[3,2- a]pyrimidine-1’,6″-dicarboxylates in good yields. The structures of all the products were characterised thoroughly by NMR, IR and HRMS together with X-ray crystallographic analysis.

SYNTHESIS OF NITROMETHYL-, N -METHYLINDOLYL-, OR N -METHYLINDOLYLNITROMETHYL- SUBSTITUTED 1,4-BENZOTHIAZIN(DIAZIN)ONES AND 3-METHYL-1,4-BENZOXAZINONES FROM ALKYL 3-NITROACRYLATES

На основе реакций алкил-3-нитроакрилатов и этил-2-(1-метил-1H-индол-3-ил)-3-нитроакрилата с о-аминотиофенолом, о-аминофенолом, о-фенилендиамином и их аналогами осуществлен синтез и изучено строение 2-(нитрометил)-2H-1,4-бензотиазин-3(4H)-она, 2-(1-метил-1H-индол-3-ил)-2-(нитрометил)-2H-1,4-бензотиазин-3(4H)-она, 3-метил-2H-1,4-бензоксазин-2-онов и 3-(1-метил-1H-индол-3-ил)хиноксалин-2(1H)-онов.

Theophylline Supported on Modified Silica‐Coated Magnetite Nanoparticles as a Novel, Efficient, Reusable Catalyst in Green One‐Pot Synthesis of Spirooxindoles and Phenazines

AbstractIn the present work, theophylline immobilized on superparamagnetic Fe3O4@SiO2 nanoparticles were prepared via a multistep method and was fully characterized by means of fourier transform infrared (FT‐IR) spectroscopy, X‐ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE‐SEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), energy dispersive X‐ray analysis (EDX), vibration sample magnetometry (VSM), N2 adsorption‐desorption isotherm analysis, temperature‐programmed desorption of carbon dioxide (CO2‐TPD) and elemental analysis. The catalytic performance of this novel nanomagnetic catalyst has been studied in the synthesis of spirooxindole derivatives via a one‐pot three‐component reaction of isatin derivatives, malononitrile or ethyl 2‐cyanoacetate, and 5‐amino‐1,3‐dimethyluracil in excellent yields under reflux conditions in water. Also, the highly efficient, green and economical synthesis of poly‐substituted benzo[a]pyrano‐[2, 3‐c]phenazine derivatives from four component reaction of 2‐hydroxynaphthalene‐1,4‐dione, diamines, aldehydes, and malononitrile in the presence of this basic magnetic catalyst has been developed. In addition, the used catalyst could be separated conveniently from the reaction system for up to 6 runs without significant loss of its catalytic efficiency.

Determination and application of the solubility product of metal xanthate in mineral flotation and heavy metal removal in wastewater treatment

The reactions of ethyl and butyl xanthates with Pb2+, Cd2+ and Zn2+ were investigated to determine the solubility products of metal xanthates using UV/Visible spectroscopic method and software WinSGW and MEDUSA. The effects of solution pH, chemical reactions and ionic strength on the determination of solubility products of metal xanthates were investigated. For a given metal, the solubility product of metal xanthate was found to decrease with the increase of the carbon chain length of the alkyl group. The determined solubility products of metal xanthates were in the order of ZnX2 > CdX2 > PbX2 and M(EX)2 > M(BX)2. The accurate Ksp constant allowed more accurate calculation of the minimal concentration of xanthate ions for treating heavy metal-containing waste water to selectively separate metal ions, avoiding the potential presence of toxic xanthates in the treated water.

Convenient synthetic path to ethyl 1-aryl-5-formyl-1H-1,2,3-triazole-4-carboxylates and 1-aryl-1,5-dihydro-4H-[1,2,3]triazolo[4,5-d]pyridazin-4-ones

A convenient method for selective synthesis of ethyl 1-aryl-5-formyl-1H-1,2,3-triazole-4-carboxylates and 1-aryl-1,5-dihydro-4H-[1,2,3]-triazolo[4,5-d]pyridazin-4-ones has been developed. New ethyl 1-aryl-5-(diethoxymethyl)-1H-1,2,3-triazole-4-carboxylates were prepared by the reaction of different aryl azides and ethyl 4,4-diethoxy-3-oxobutanoate and readily converted into ethyl 1-aryl-5-formyl-1H-1,2,3-triazole-4-carboxylates in high overall yields. Such aldehydes were found to be reactive in several condensation reactions. Reaction of ethyl 1-aryl-5-formyl-1H-1,2,3-triazole-4-carboxylates and hydrazine provided 1-aryl-1,5-dihydro-4H-[1,2,3]triazolo[4,5-d]-pyridazin-4-ones in excellent yields.

Palladium-Catalyzed Regioselective Coupling of Secondary Propargyl Carbonates and Ethyl 2-(pyridin-2-yl)acetate Derivatives: Facile Access to C-3 Benzylated Indolizines

A palladium-catalyzed ligand controlled regioselective ­coupling reaction of secondary propargyl carbonates and ethyl 2-(pyridin-2-yl)acetate derivatives has been described, leading to C-3 benzyl­ated indolizines for the first time in moderate to good yields. DBFphos as the ligand is crucial to this high regioselective annulation reaction, and a plausible reaction mechanism has been proposed.

One-pot synthesis of 3-(furan-2-yl)-4-hydroxy-2H-chromen-2-ones using K10 montmorillonite clay as heterogeneous catalyst

A facile and efficient one-pot synthesis of 3-(furan-2-yl)-4-hydroxy-2H-chromen-2-ones was developed. The reaction of ethyl 3-(2-hydroxyphenyl)-3-oxopropanoates and 2,5-dimethoxy-2,5-dihydrofuran were performed in presence of K10 Montmorillonite Clay heterogeneous catalyst under the solvent-free condition at 80 °C for 1 h, and followed by further converted to 3-(furan-2-yl)-4-hydroxy-2H-chromen-2-ones via refluxing in the alkaline EtOH solution for 0.5 h. The demonstrate method not only avoided the usage of any expensive transition-metals, but also eliminated the tedious intermediate purification. Moreover, due to the wide functional group tolerance, it could be applied to various substrates and gave product in good to excellent yields.

Synthesis of nitromethyl-, N-methylindolyl-, or N-methylindolylnitromethyl-substituted 1,4-benzothiazin(diazin)ones and 3-methyl-1,4-benzoxazinones from alkyl 3-nitroacrylates

The reactions of alkyl 3-nitroacrylates and ethyl 2-(1-methyl-1H-indol-3-yl)-3-nitroacrylate with о-aminothiophenol, о-aminophenol, о-phenylenediamine, and their substituted analogs were used for the preparation of 2-(nitromethyl)-2H-1,4-benzothiazin-3(4H)-one, 2-(1-methyl-1H-indol-3-yl)-2-(nitromethyl)-2H-1,4-benzothiazin-3(4H)-one, 3-methyl-2H-1,4-benzoxazin-2-ones, and 3-(1-methyl-1H-indol-3-yl)quinoxalin-2(1H)-ones that were structurally characterized.

A simple and efficient synthesis of new fluorophore 4-hydroxy pyrazolo[1,5-a]pyridines through a tandem reaction

The cascade reaction of ethyl pyrazole-5-carboxylate with α, β-unsaturated ester leading to 4-hydroxy pyrazolo[1,5-a]pyridine derivatives has been developed. A possible mechanism is proposed. The resulting pyrazolo[1,5-a]pyridines present strong fluorescence in solutions.

Synthesis, Cytotoxicity Evaluation, Molecular Docking and Utility of Novel Chalcones as Precursors for Heterocycles Incorporating Pyrazole Moiety.

Chalcones, 2-pyrazolines and thiazoles have been reported to possess various pharmacological activities. Synthesis of new chalcones and utilizing them as a building block for constructing a series of thiazole derivatives and evaluating some of them as anticancer agents. The new compounds were synthesized via stirring at room temperature or thermal heating. Cytotoxic evaluation of the new synthesized compounds was tested using the method of Skehan et al. Moreover, the computational studies were performed using MOE 2014.09 software. A series of new chalcones were prepared by the reaction of ethyl 3-acetyl-1-aryl-5-methyl- 1H-pyrazole-4-carboxylate with a number of substituted benzaldehydes. One of these chalcones was used as a building block for constructing a pyrazoline ring via its reaction with thiosemicarbazide. The produced carbothioamide derivative was used for the preparation of two series of thiazole derivatives by its reaction with a number of hydrazonoyl chlorides. Moreover, reaction of 3- acetylpyrazole thiosemicarbazone derivative with a number of N-aryl-2-oxopropane hydrazonoyl chlorides afforded 5-arylazothiazole derivatives. The assigned structures for all the newly synthesized compounds were confirmed on the basis of elemental analyses and spectral data. Some of the newly synthesized chalcones and thiazoles were tested for their cytotoxicity against human colon carcinoma cell line (HCT-116) and the molecular docking was carried out on the most active compound 3f. The results of the anticancer activity revealed that compounds 3f, 3e, 3c and 3b have promising activities compared with the standard drug Doxorubicin. Moreover, the computational studies confirm the results of biological activity. Also, the ADME profile study showed that compound 3f can be considered as a promising drug by conducting good pharmacokinetic and medicinal chemistry tests.

Ultrasound Assisted Synthesis of Quinoline Derivatives in the Presence of SnCl2·2H2O as a Precatalyst in Water: Evaluation of their Antibacterial Activities.

SnCl2·2H2O has been used as a convenient precatalyst for the one-pot and rapid synthesis of 2-substituted quinolines under ultrasound irradiation in water. The reaction involved a 3-component reaction of aniline, aldehydes, and ethyl 3,3-diethoxypropionate in the presence of aerial oxygen to give the desired products in good yields. Several of these compounds showed antibacterial activities when tested against gram-positive and gram-negative species. One compound i.e. 4b showed promising activities across both the species.

Design, synthesis and spectroscopic and crystallographic characterisation of novel functionalized pyrazole derivatives: biological evaluation for their cytotoxic, angiogenic and antioxidant activities

The current study presents the synthesis of functionalized pyrazoles (18–29) through 3 + 2 annulation reaction of ethyl 2-(arylidene)-3-oxobutanoates (8–13) with phenylhydrazine hydrochlorides (14–17) in acetic acid under reflux conditions. Structures of the synthesized new compounds were characterized by spectral and single-crystal X-ray diffraction studies. Preliminary assessment on their biological activities showed that compounds 19, 23 and 28 have anticancer and antiangiogenic properties and compounds 20, 24 and 26 have excellent diphenylpicrylhydrazyl (DPPH) radical scavenging activities. Detailed quantitative structure–activity relationship (QSAR) analysis provided insights into the molecular features that might have contributed towards increasing potency of inhibition. In summary, we present a study that has successfully demonstrated the synthesis of novel pyrazole analogues that display anticancer, antiangiogenic and DPPH free radical scavenging activities, making them lead molecules of choice for further development.