Reaction Of Acetate Research Articles

Eosin Y as a direct HAT photocatalyst for the synthesis of tetrahydrodipyrazolopyridines under white LED irradiation

A facile and efficient synthetic protocol has been developed for the synthesis of biologically privileged tetrahydrodipyrazolopyridines via visible light mediated one pot pseudo-six component reaction of ethyl acetoacetate, hydrazine hydrate, multifarious aldehydes and ammonium acetate (Knoevenagel condensation-Michael addition) by using metal-free, inexpensive eosin Y organic dye as a direct hydrogen atom transfer (HAT) catalyst at room temperature in open air condition. Mild condition, good yields, environment-friendly, high atom economy and good functional group tolerance of an extensive range of both electron-withdrawing and electron-donating groups are extra features of this approach. Additionally, this methodology is also appropriate for multi-gram scale, which enlighten the potentiality of using this reaction for industrial purposes.

Synthesis and characterization of Se doped Fe3O4 nanoparticles for catalytic and biological properties

In this study, Se-doped Fe3O4 with antibacterial properties was synthesized using by a coprecipitation method. The chemistry and morphology of the Se doped Fe3O4 nanocomposite were characterized by energy-dispersive X-ray spectroscopy, field-emission scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry, and Brunauer–Emmett–Teller spectroscopy. The antibacterial activity of the Fe3O4/Se nanocomposite was examined against G+ (Gram-positive) and G− (Gram-negative) bacteria, in the order Staphylococcusaureus, Staphylococcussaprophyticus, Pseudomonasaeruginosa, Klebsiellapneumonia, and Escherichiacoli, which are the most harmful and dangerous bacteria. Fe3O4/Se, as a heterogeneous catalyst, was successfully applied to the synthesis of pyrazolopyridine and its derivatives via a one-pot four-component reaction of ethyl acetoacetate, hydrazine hydrate, ammonium acetate, and various aromatic aldehydes. Fe3O4/Se was easily separated from the bacteria-containing solution using a magnet. Its admissible magnetic properties, crystalline structure, antibacterial activity, mild reaction conditions, and green synthesis are specific features that have led to the recommendation of the use of Fe3O4/Se in the water treatment field and medical applications. Direct Se doping of Fe3O4 was successfully realized without additional complicated procedures.

Polyaromatic Group Embedded Cd(II)-Coordination Polymers for Microwave-Assisted Solvent-Free Strecker-Type Cyanation of Acetals.

In this work, two new 1D Cd(II) coordination polymers (CPs), [Cd(L1)(NMF)2]n (1) and [Cd(L2)(DMF)(H2O)2]n·n(H2O) (2), have been synthesized, characterized and employed as catalysts for the microwave-assisted solvent-free Strecker-type cyanation of different acetals. Solvothermal reaction between the pro-ligand, 5-{(pyren-1-ylmethyl)amino}isophthalic acid (H2L1) or 5-{(anthracen-9-ylmethyl)amino}isophthalic acid (H2L2), and Cd(NO3)2.6H2O in the presence of NMF or DMF:THF solvent, produces the coordination polymer 1 or 2, respectively. These frameworks were characterized by single-crystal and powder X-ray diffraction analyses, ATR-FTIR, elemental and thermogravimetry analysis. Their structural analysis revealed that both CPs show one-dimensional structures, but CP 1 has a 1D double chain type structure whereas CP 2 is a simple one-dimensional network. In CP 1, the dinuclear {Cd2(COO)4} unit acts as a secondary building unit (SBU) and the assembly of dinuclear SBUs with deprotonated ligand (L12-) led to the formation of a 1D double chain framework. In contrast, no SBU was observed in CP 2. To test the catalytic effectiveness of these 1D compounds, the solvent-free Strecker-type cyanation reactions of different acetals in presence of trimethylsilyl cyanide (TMSCN) was studied with CPs 1 and 2 as heterogenous catalysts. CP 1 displays a higher activity (yield 95%) compared to CP 2 (yield 84%) after the same reaction time. This is accounted for by the strong hydrogen bonding packing network in CP 2 that hampers the accessibility of the metal centers, and the presence of the dinuclear Cd(II) SBU in CP 1 which can promote the catalytic process in comparison with the mononuclear Cd(II) center in CP 2. Moreover, the recyclability and heterogeneity of both CPs were tested, demonstrating that they can be recyclable for at least for four cycles without losing their structural integrity and catalytic activity.

Aluminosilicates Catalysts Synthesis from Low-Grade Indonesian Kaolin for the Acetalization Reaction

Aluminosilicate and ZSM-5 catalyst were synthesized from local materials, low-grade Indonesian kaolin. High quartz impurities content in the low-grade kaolin was successfully reduced by the consecutive treatment process including washing, centrifugation, and Fe3+ treatment. All the synthesized catalyst showed mesoporous structure with pore diameter around 3.5 nm. The catalytic activity was investigated in the acetalization of 3,4-dimethoxybenzaldehyde and propylene glycol, then the effect of a different base (TPAOH and NaOH) and Fe3+ addition in the treatment process to the catalytic activity was discussed. The catalytic activity of the aluminosilicate catalyst outperforms the ZSM-5. Interestingly, it is found that the catalytic activity of the catalyst can be enhanced by addition of Fe3+ in the aluminosilicate, with enhanced the conversion from 32.2% to 81.6%, whereas Fe3+ addition to ZSM-5 showed slightly increased conversion value from 0% to 3.65%. All catalysts showed high selectivity of 100% of the reaction product 2-(3,4-dimethoxy-phenyl)-4-methyl-1,3-dioxolane.

Trialkylphosphonium oxoborates as C(sp3)-H oxyanion holes and their application in catalytic chemoselective acetalization.

The use of trialkylphosphonium oxoborates (TOB) as catalysts is reported. The site-isolated borate counter anion in a TOB catalyst increases the availability of C(sp3)-H to interact with electron donor substrates. The catalytic protocol is applicable to a wide range of substrates in the acetalization reaction and provides excellent chemoselectivity in the acetalization over thioacetalization in the presence of alcohols and thiols, which is otherwise hard to achieve using typical acid catalysts. Experimental and computational studies revealed that the TOB catalysts have multiple preorganized C(sp3)-Hs that serve as a mimic of oxyanion holes, which can stabilize the oxyanion intermediates via multiple C(sp3)-H non-classical hydrogen bond interactions.

Samarium(III) Triflate as an Efficient and Reusable Catalyst for the Facile Synthesis of 1,2,4,5-Tetrasubstituted Imidazoles

An efficient, simple, and green four-component reaction for synthesizing 1,2,4,5-tetrasubstituted imidazoles is developed. In present work exploring the use of Samarium triflate as a heterogeneous catalyst for the four-component reaction of aldehydes, aromatic amines, benzil, and ammonium acetate. The current approach offers many advantages, such as excellent yields, shortening of reaction time, reusability of catalyst, and use of mild reaction conditions.

Synthesis of 2-iminothiazolidin-4-ones via copper-catalyzed [2 + 1 + 2] tandem annulation.

In this paper, an efficient synthesis of 2-iminothiazolidin-4-ones through a copper-catalyzed tandem annulation reaction of alkyl amines, isothiocyanates and diazo acetates is presented. Notable advantages of this [2 + 1 + 2] cyclization methodology include readily accessible starting materials, simple operation, mild reaction conditions, high yields, step-economy and diverse functional group tolerance. In addition, the reaction is applicable to the gram scale synthesis and the preparation of bioactive molecules.

Synthesis of 3-substituted 2,3-dihydropyrazino[1,2-a]indol-4(1H)-ones by sequential reactions of 2-indolylmethyl acetates with α-amino acids.

The synthesis of 2,3-dihydropyrazino[1,2-a]indol-4(1H)-ones from the sequential reaction of amino acid methyl esters with readily available indole-2-ylmethyl acetates is described. The reaction proceeds in situ under basic conditions of highly unstable and reactive 2-alkylideneindolenines followed by Michael-type addition of α-amino acid methyl esters/intramolecular cyclization.

Efficient synthesis of fully renewable, furfural-derived building blocks via formal Diels-Alder cycloaddition of atypical addends.

Diels-Alder (DA) cycloaddition of furanics is emerging as a key transformation in circular chemistry, providing access to highly versatile, biobased platform molecules. Further development of this technology into viable industrial applications faces major challenges, a notorious one being the lack of reactivity of the most readily available furans, i.e. the furfural derivatives. Herein we describe the remarkably-facile intramolecular DA reaction of allyl acetals of different furfurals to efficiently afford formal DA adducts with the atypical, unreactive dienophile allyl alcohol. Our methodology gives access to unprecedented oxanorbornene derivatives in high chemo-, regio- and stereoselectivity, which can be readily diversified into valuable products. This offers the potential of scalable production of renewable chemical building blocks from cheap, bioderived platform molecules.

Synthesis, antioxidant activity, antimicrobial efficacy and molecular docking studies of 4-chloro-2-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazol-2-yl)phenol and its transition metal complexes.

Herein, a one-pot synthesis of tetra-substituted imidazole, 4-chloro-2-(1-(4-methoxyphenyl)-4,5-diphenyl-1H-imidazol-2-yl)phenol (HL), is reported by the reaction of benzil, 5-bromosalicylaldehyde, ammonium acetate and anisidine. The synthesized imidazole was reacted with salts of 1st row transition metals (Co(ii), Ni(ii), Cu(ii), Mn(ii) and Zn(ii)) to obtain metal complexes. The structure of the compounds was confirmed using various spectroscopic and analytical techniques. HL, which is crystalline, was characterized by SC-XRD. Subsequently, the synthesized compounds were evaluated for their antioxidant and antimicrobial activities. Antimicrobial studies revealed the more noxious nature of metal complexes compared to ligand against various strains of bacteria and fungi. Molecular docking results based on the binding energy values also supported the experimental results of the antioxidant activities of the compounds. HL was found to be a better antioxidant than metal complexes. For a better insight into the structure, computational studies of the compounds were also carried out. A clear intra-molecular charge transfer was perceived in the ligand and its metal complexes. The transfer integral values for holes (36.48 meV) were found to be higher than the electron transfer integrals (24.76 meV), which indicated that the ligand would be a better hole transporter. According to the frontier molecular orbitals of the dimer, the charge transfer within the molecule is found from monomer 1 to 2.

Synthesis of functionalized 3-aryl-3H-benzofuranone derivatives from aryl acetate via [3 + 2] annulation of 1,4-dihydroxy-2-naphthoic acid ester.

A novel [3 + 2] cascade reaction of aryl acetate with 1,4-dihydroxy-2-naphthoic acid ester by cooperative catalysis of isothiourea and vanadium is developed. The key step of the reaction is that the C1-ammonium enolates generated from aryl acetate will cycloadduct to 1,4-naphthoquinone intermediates. 3-Aryl-3H-benzofuranone derivatives can be prepared in medium to good yields under mild conditions.

A multiscale simulation on the formation mechanism of crotonaldehyde and the influence of operating parameters on the process during the production of vinyl acetate from acetylene

Excessive operating temperatures and pressures can cause uncontrolled temperatures and even explosions in acetylene to vinyl acetate reactions.

Biphenyl aldehyde-based ternary catalytic system catalyzed Tsuji–Trost allylation of N-unprotected amino acid esters

A highly efficient biphenyl aldehyde-based ternary catalytic system is rationally designed and applied in the direct α-allylation reaction of N-unprotected amino acid esters and allyl alcohol acetates. The chemoselectivity of C-allylation and N-allylation is efficiently controlled and various racemic α,α-disubstituted amino acid esters are generated in good-to-high yields. The target products can be readily converted into structurally diverse α,α-disubstituted amino acids at a gram scale.

Intensification of interesterification of sustainable feedstock as mahua oil for biodiesel production

ABSTRACT In the current work, the ultrasonic horn induced cavitation was used as an intensification approach for the production of fatty acid methyl esters (FAME), i.e. biodiesel and triacetin as a by-product from the reaction of mahua oil selected as sustainable feedstock and methyl acetate (MA). The effects of process variables like reaction temperature, mahua oil to methyl acetate molar ratio, reaction time, catalyst loading, duty cycle, and power on yield of FAME have been studied and the results elucidated best conditions for maximum fatty acid methyl ester yield of 96% as time of 50 min, temperature of 50C, molar ratio of 1:8, duty cycle of 40%, ultrasonic power of 70 W and catalyst loading of 1 wt%. For conventional approach based on only stirring, the yield was 61% under otherwise similar conditions. Kinetic study was performed to estimate the order of reaction and the activation energy. It was shown that the kinetics was well fitted to first-order reaction and activation energy was observed as 25.9 kJ/mol. The study revealed the effective application of ultrasonic horn in intensification of biodiesel production using interesterification reaction resulting in considerably higher yield of FAME.

Preparation and Characterization of NiCoFe2O4 Nanoparticles as an Effective Catalyst for the Synthesis of Trisubstituted Imidazole Derivatives Under Solvent-free Conditions.

In this study, NiCoFe2O4 nanoparticles were prepared and used as a reactive catalyst for the synthesis of trisubstituted imidazoles. The multicomponent reactions of aromatic aldehydes, benzil and ammonium acetate were carried out under solvent-free and conventional heating conditions. In this reaction, some imidazole derivatives with high purity, short reaction times and high yields were obtained. The prepared nanocatalyst was characterized by FT-IR, XRD, EDX, VSM and SEM techniques. Moreover, the organic products were identified by melting point, FT-IR and 1H NMR analyzes.

Computational and experimental investigation on biological and photophysical properties of high yielded novel aryl-substituted pyrazolone analogue

A series of new aryl-substituted pyrazolone derivatives 5(a-h) were synthesised via the Baylis-Hillman acetate reaction with pyrazolones and tested for antifungal, antibacterial, and antioxidant properties in vitro. Among the tested molecules 5d and 5e show good in vitro antifungal and antibacterial activities due to the presence of fluorine, which enhances the absorption rate by increasing lipid solubility and improves the pharmacological activity. It is also evident from the results obtained from structure-activity relationship (SAR) studies. Further, the photophysical properties of synthesized compounds were theoretically estimated using the ab-intio technique. The ground state optimization and HOMO–LUMO energy levels are calculated using the DFT-B3LYP-6-311 basis set. Using the theoretically estimated HOMO–LUMO value, global chemical reactivity descriptor parameters are estimated, and the result shows that compounds 5d and 5e have a higher electronegative and electrophilicity index than other molecules. Overall results suggest that, fluorine substituted pyrazolone derivatives show good photophysical, SAR, and biological properties.

Influence of Temperature–Time Parameters and System Composition on Kinetics of Acetalization Reaction in Preparation of Polyvinyl Formal Foam from Polyvinyl Alcohol Solution

Influence of Temperature–Time Parameters and System Composition on Kinetics of Acetalization Reaction in Preparation of Polyvinyl Formal Foam from Polyvinyl Alcohol Solution

Synthesis, Characterization and Antimicrobial Activity of Isoxazoline Derivatives

In present study isoxazoline derivatives were synthesized and antimicrobial activity of different derivatives were checked with various microbial stain. Various intermediates was synthesized and characterized in between time to time by chromatography using TLC. An isoxazoline series of compounds were synthesized by condensation reaction of phenyl ethyl acetate with substituted benzaldehyde in presence of alcoholic sodium hydroxide to get intermediate phenethyl cinnamate (chalcones), which were further treated with hydroxylamine hydrochloride in presence of sodium hydroxide to get isoxazoline derivatives. The synthesized compounds were characterized on the basis of their spectral (IR) data and evaluated for the antimicrobial activity by using Zone of Inhibition by cup plate method.

Synthesis of polymer-functionalized β-cyclodextrin, Mg2+ doped, coating magnetic Fe3O4 nanoparticle carriers for penicillin G acylase immobilization

Based on the beneficial effects of magnesium ions on biomolecules, it was first introduced into enzyme immobilization carriers to promote the comprehensive performance of immobilized enzymes in repeated use. Firstly, Fe3O4 nanoparticles (NPs) were prepared by the inverse microemulsion method, then, Mg2+ was doped in the process of coating β-cyclodextrin (β-CD) on the surface of Fe3O4 NPs. Afterward, through acetal reaction, glutaraldehyde (GA) was grafted to the material’s surface to obtain Mg2+-Fe3O4 @ β-CD-g-GA NPs, and covalent bond immobilization of Penicillin G acylase (PGA) was realized by the Schiff base reaction of the carriers’ aldehyde group and PGA’s amino group. After optimization of process conditions, the results show that the performances of the immobilized PGA achieve the best, when the concentration of the enzyme solution is 3.00 vol%, pH is 8.0, the immobilization time is 30 h, and the immobilization temperature is 37 °C. Its enzyme activity recovery (EAR), enzyme activity (EA) and enzyme loading capacity (ELC) are 95.6%, 31997 U/g, 110 mg/g, respectively. Lastly, the operational stability, reusability, and storage stability of Mg2+-Fe3O4 @ β-CD-g-GA-PGA NPs were researched. Relative to free PGA, immobilized PGA has better operation stability and storage stability. After 11 repeated uses, the immobilized PGA still has 56% of the initial vitality, and the carrier recovery (Re) is 86.6%.

Experimental and Theoretical Investigation on Imidazole Derivatives Using Magnetic Nanocatalyst: Green Synthesis, Characterization, and Mechanism Study

The green synthesis of 4,5-diphenyl-1H-imidazole derivatives was studied experimentally and theoretically through a one-pot, three-component reaction of diverse aldehydes, ammonium acetate, and benzil using Fe3O4@C@PrNHSO3H nanoparticles under solvent-free conditions. The core-shell magnetic nanoparticles of Fe3O4@C@PrNHSO3H were introduced as an effective, environmentally friendly, and magnetically removable catalyst in the reaction. The recovered catalyst could be used eight times with admirable catalytic activity. Before entering the laboratory, the synthesis of imidazoles was studied from a computational point of view to find the most plausible mechanism and select the appropriate raw materials. Three probable mechanistic paths were considered. Density functional theory (DFT) calculations confirmed the following mechanism: (1) reaction of benzil and ammonia to form iminoethanone, (2) reaction of aldehyde and ammonia to form imin, (3) reaction of imin with iminoethanone and ring formation, and (4) rearrangement to produce 4,5-triphenyl-1H-imidazole. The results were affirmed by the frontier molecular orbitals, natural bond orbital analyses, and molecular electrostatic potential calculations. HIGHLIGHTS The green synthesis of 4,5-diphenyl-1H-imidazole derivatives was studied experimentally and theoretically using Fe3O4@C@PrNHSO3H nanoparticles (NPs). Three proposal mechanisms were considered using M062X/6-311++G(d,p) to achieve the most plausible mechanism, The proposed mechanism was verified by the frontier molecular orbitals, natural bond orbital analyses, and molecular electrostatic potential calculations. The Fe3O4@C@PrNHSO3H NPs were introduced as an effective, eco-friendly and magnetically recoverable catalyst in the one-step synthesis of imidazoles. The recovered catalyst could be used eight times with admirable catalytic activity.