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14 result(s) for "Cyanoethylation"
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Yttrium nitrate promoted selective cyanoethylation of amines
The catalyst Y(NO 3 ) 3 , 6H 2 O exhibited remarkable activity in the aza-Michael addition of various aromatic and aliphatic amines with acrylonitrile at ambient temperature in a protic solvent. The method is selective for the monocyanoethylation of primary aromatic amines, aliphatic secondary amines, and sterically hindered aliphatic amines. Phenols and active methylene compounds do not undergo cyanoethylation. Thiophenol, in the presence of yttrium nitrate, promotes the polymerization of acrylonitrile. The water solubility and high catalyst stability make the process of removing the catalyst from the product easy. Direct aqueous workup of the reaction mixture could lead to the isolation of cyanoethylation products up to 99.9% purity. Graphical Abstract Selective mono- cyanoethylation at the primary aromatic amine, especially electron-rich aromatic amines Excellent regio-selectivity in the presence of Carbon and Oxygen nucleophiles The reported condition could be used to polymerize acrylonitrile in the presence of thiophenol. Reaction is facile for electron-rich aromatic amine. Highly sensitive to the steric effect at the nitrogen center
Quantitative analysis of degree of substitution/molar substitution of etherified polysaccharide derivatives
Due to the unique properties such as nontoxicity, biodegradability, availability from renewable resources, and cost-effectiveness, polysaccharides play a very important part in the science and technology field. The various chemically modified derivatives of these offer a wide range of high value-added in both food and non-food industries. Among the chemical modification, etherified polysaccharide is one of the most widespread derivatives by introducing an ether group which is commonly stable in both acidic and alkaline conditions. Hydroxyalkylation, alkylation, carboxymethylation, cationization, and cyanoethylation are some of the modifications commonly employed to prepare polysaccharides ethers derivatives. There also has been a growing tendency for creating new types of modification by combining the different means of chemical techniques. The correct determination of degree of substitution (DS)/molar substitution (MS) is crucially important. The objective of this article is to summarize developments in synthetic etherified polysaccharides, involving analytical methods for determination of MS/DS, measurement processes, and the associated mechanisms.
N-cyanoethyl polyethylenimine as a water-soluble binder for LiFePO4 cathode in lithium-ion batteries
N -cyanoethyl polyethylenimine (CN-PEI) is synthesized by modifying polyethylenimine (PEI) with acrylonitrile through a Michael addition reaction. Depending on cyanoethylation level, CN-PEI can be obtained as a form of solution, micro-emulsion or emulsion in water. CN-PEI micro-emulsion is investigated as water-soluble binder for the application of lithium iron phosphate (LFP) cathode in lithium-ion batteries. CN-PEI binder not only maintains the outstanding dispersion capability of PEI but also exhibits an excellent adhesion strength and higher ionic conductivity because of the introduction of polar cyano groups. As a result, CN-PEI binder can effectively maintain the mechanical integrity and decrease the polarization of LFP electrode during the operation of the battery. LFP electrode with CN-PEI binder exhibits good cycle stability and enhanced rate performance delivering a capacity of 99.6% at a rate of 0.5 C after 100 cycles and a high discharge capacity of 102.4 mAh g −1 at 5 C.
Effects of Synthesis Parameters on Crystallization Behavior of K-MER Zeolite and Its Morphological Properties on Catalytic Cyanoethylation Reaction
MER-type zeolite is an interesting microporous material that has been widely used in catalysis and separation. By carefully controlling the synthesis parameters, a procedure to synthesize K-MER zeolite crystals with various morphologies has been developed. The silica, water and mineralizer content in the synthesis gel, as well as crystallization time and temperature, have a profound impact on the crystallization kinetics, resulting in zeolite solids with various degrees of crystallinity, crystal sizes and shapes. K-MER zeolite crystals with nanorod, bullet-like, prismatic and wheatsheaf-like morphologies have been successfully obtained. The catalytic performances of the K-MER zeolites in cyanoethylation of methanol, under novel non-microwave instant heating, have been investigated. The zeolite in nanosize form shows the best catalytic performance (94.1% conversion, 100% selectivity) while the bullet-like zeolite gives poorest catalytic performance (44.2% conversion, 100% selectivity).
Synthesis and properties of tetrazole-containing polyelectrolytes based on chitosan, starch, and arabinogalactan
The synthesis of tetrazole-containing derivatives of chitosan, starch, and arabinogalactan was carried out by a sequence of reactions including cyanoethylation of polysaccharides and subsequent azidation of cyanoethyl derivatives. The reaction of cyanoethylation of polysaccharides with acrylonitrile proceeds in the temperature range 40–60°C in the presence of NaOH. The transformation of nitrile groups into tetrazole rings (azidation) of cyanoethylated polysaccharide derivatives was carried out with a mixture of sodium azide with ammonium chloride in DMF at 105°C. The reaction with the participation of derivatives of starch and arabinogalactan is characterized by the degree of conversion of nitrile groups into tetrazole rings, which is close to the maximum. The introduction of unsubstituted tetrazole rings into the structure of polysaccharides of acidic N–H substantially changes some of their properties. Like other carbo- and hetero-chain polymers containing N–H unsubstituted tetrazole rings in the structure, tetrazolated polysaccharides exhibit the properties of acidic polyelectrolytes. Tetrazole-containing derivatives of chitosan exhibit the properties of polyampholytes. The presence of tetrazole rings in the structure of modified polysaccharides allows the reaction with epoxy compounds to yield network polymers capable of limited swelling in aqueous media with the formation of polyelectrolyte hydrogels.
Fused Thiopyrano2,3-dthiazole Derivatives as Potential Anticancer Agents
rel-(5aR,11bR)-3,5a,6,11b-tetrahydro-2H,5H-chromeno[4',3':4,5]thiopyrano[2,3-d][1,3]thiazol-2-ones formed by the stereoselective Knoevenagel-hetero-Diels-Alder reaction were functionalized at the nitrogen in position 3 via reactions of alkylation, cyanoethylation, and acylation. The synthesized compounds were evaluated for their anticancer activity in NCI60 cell lines. Among the tested compounds, 3f was found to be the most active candidate with the greatest influence on leukemia, non-small cell lung cancer, colon cancer, CNS cancer, melanoma, prostate cancer, and breast cancer subpanel cell lines with GI(50) values over a range of 0.37-0.67 μM.
Highly Basic and Dipolar Layered Double Hydroxides Enhance Catalysis of Cyanoethylation of Alcohols
Layered double hydroxides (LDH), magnesium–aluminum–carbonates and magnesium–gallium–aluminum–carbonates, were synthesized by sol–gel incorporating during synthesis a part of aluminum as (AlF 6 ) 3− blocks in order to incorporate F − as a part of brucite-like layers and not as compensating anions. Structural, textural and surface properties of resulting fluorinated were characterized. Particularly, presence the fluorine as a part of brucite-like layers influenced directly polarity and hydrogen bonding acceptor character at surface of materials. These modifications at surface of LDH greatly changed their catalytic properties. Cyanoethylation reaction between acrylonitrile and methanol was catalyzed by both fluorine-free and fluorinated LDH, pointing out a clear influence of fluorine on the conversion and rate reaction. Graphical Abstract
Efficient Delivery of Plasmid DNA Using Cholesterol-Based Cationic Lipids Containing Polyamines and Ether Linkages
Cationic liposomes are broadly used as non-viral vectors to deliver genetic materials that can be used to treat various diseases including cancer. To circumvent problems associated with cationic liposome-mediated delivery systems such as low transfection efficiency and serum-induced inhibition, cholesterol-based cationic lipids have been synthesized that resist the effects of serum. The introduction of an ether-type linkage and extension of the aminopropyl head group on the cholesterol backbone increased the transfection efficiency and DNA binding affinity compared to a carbamoyl-type linkage and a mono aminopropyl head group, respectively. Under optimal conditions, each liposome formulation showed higher transfection efficiency in AGS and Huh-7 cells than commercially available cationic liposomes, particularly in the presence of serum. The following molecular structures were found to have a positive effect on transfection properties: (i) extended aminopropyl head groups for a strong binding affinity to plasmid DNA; (ii) an ether linkage that favors electrostatic binding to plasmid DNA; and (iii) a cholesterol backbone for serum resistance.
Synthesis of Oligodeoxynucleotides Using Fully Protected Deoxynucleoside 3′-Phosphoramidite Building Blocks and Base Recognition of Oligodeoxynucleotides Incorporating N3-Cyano-Ethylthymine
Oligodeoxynucleotide (ODN) synthesis, which avoids the formation of side products, is of great importance to biochemistry-based technology development. One side reaction of ODN synthesis is the cyanoethylation of the nucleobases. We suppressed this reaction by synthesizing ODNs using fully protected deoxynucleoside 3′-phosphoramidite building blocks, where the remaining reactive nucleobase residues were completely protected with acyl-, diacyl-, and acyl-oxyethylene-type groups. The detailed analysis of cyanoethylation at the nucleobase site showed that N3-protection of the thymine base efficiently suppressed the Michael addition of acrylonitrile. An ODN incorporating N3-cyanoethylthymine was synthesized using the phosphoramidite method, and primer extension reactions involving this ODN template were examined. As a result, the modified thymine produced has been proven to serve as a chain terminator.
Synthesis and characterization of cyanoethyl hemicelluloses and their hydrated products
A novel type of hemicellulosic derivative, cyanoethyl hemicelluloses (CEH), derived from xylan-rich hemicelluloses and acrylonitriles was successfully prepared in aqueous sodium hydroxide. The reaction was performed under various reaction conditions such as temperature, time, the amount of sodium hydroxide, and the molar ratio of acrylonitrile to anhydroxylose units in hemicelluloses, and the relationship between reaction condition and DS of the CEH was investigated in detail. A series of CEH with degree of substitution of cyanoethyl (DS C≡N ) ranging from 0.23 to 1.64 were obtained. Importantly, CEH can undergo various reactions and convert into other macromolecules with functional groups like carboxylic acids, amine, aldehyde etc. In this work, H 2 O 2 /K 2 CO 3 /DMSO was used to hydrate CEH into carbamoylethyl hemicelluloses at room temperature. FT-IR, 1 H and 13 C NMR spectra confirmed the introduction of cyanoethyl groups into the hemicelluloses backbone and the presence of carbamoylethyl groups in the hydrated product. In addition, in the nucleophilic addition reaction, the hydroxyl groups at C-3 position of the anhydroxylose units were more active than these at C-2. TGA/DTG showed that CEH had lower thermal stability than hemicelluloses. This work provided a new macromolecule which can be used as a versatile platform for producing other functional macromolecules.