Alkyl Vinyl Research Articles

Nickel-Catalyzed Cross-Electrophile Coupling of Vinyl Acetates and Alkyl Bromides

Nickel-Catalyzed Cross-Electrophile Coupling of Vinyl Acetates and Alkyl Bromides

Cationic Polymerization of Phenyl Vinyl Ethers: Investigations of the Propagation Mechanism, the Living Polymerization of Ortho-Substituted Derivatives, and the Step-Growth Polymerization of Divinyl Derivatives

The cationic polymerization of phenyl vinyl ether (PhVE) was investigated to elucidate the reason it is much more difficult to obtain high-molecular-weight polymers of PhVE than with alkyl vinyl et...

Photocatalyst-free visible light driven synthesis of (E)-vinyl sulfones from cinnamic acids and arylazo sulfones

A photocatalyst-free visible light mediated decarboxylative sulfono functionalization protocol has been explored for the synthesis of (E)-vinyl sulfones from cinnamic acids and bench-stable arylazo sulfones. The latter have been utilized as sulfonyl radical precursors under blue LED irradiation along with Cs2CO3, air and KI to obtain the vinyl aryl sulfones as well as vinyl alkyl sulfones in moderate to excellent yields. Besides the non-photocatalytic conditions, high ecosustainability, low cost, ease of operation and access to vinyl alkyl sulfones are certain indispensable traits of the developed method.

A visible-light photocatalytic thiolation of aryl, heteroaryl and vinyl iodides.

The general catalytic synthesis of aryl and vinyl thioethers from readily available halides remains a challenge. Herein we report a unified method for the thiolation of aryl and vinyl iodides with dialkyl disulfides using visible light photoredox catalysis. A range of thioether products bearing diverse functional groups can be accessed in high yield and with excellent chemoselectivity. We demonstrate the versatility of this method through the expedient synthesis of a family of thioether-rich natural products. A detailed investigation of the photocatalytic mechanism is presented from both steady-state and time-resolved luminescent quenching as well as transient absorption spectroscopy experiments.

Новые сополимеры виниловых мономеров с вклю-чением стирола как перспективные модификаторы вязкости смазочных масел

The method of the compensating copolymerization was used for the synthesis of compositionally homogeneous binary and ternary copolymers of vinyl butyl ether, styrene and alkyl (meth)acrylates (butyl acrylate, butyl methacrylate and 2-ethylhexyl acrylate) with a comparable ratio of all components. New copolymers exhibit low susceptibility to mechanical degradation in dioctyl sebacate solution that is a synthetic base of lubricants. The latter indirectly confirms the composition homogeneity and gives an opportunity of their application as an import substitution of the oils thickeners.

Enantioselective Synthesis of β-Fluoro Amines via β-Amino α-Fluoro Nitroalkanes and a Traceless Activating Group Strategy.

Preparation of a range of enantioenriched β-fluoro amines (α,β-disubstituted) is described in which the nitrogen and fluorine atoms are attached to sp3-hybridized carbons. The key finding is a chiral bifunctional Brønsted acid/base catalyst that can deliver β-amino-α-fluoro nitroalkanes with high enantio- and diastereoselection. A denitration step renders the nitro group "traceless" and delivers secondary, tertiary, or vinyl alkyl fluorides embedded within a vicinal fluoro amine functional group. A synthesis of each possible stereoisomer of a β-fluoro lanicemine illustrates the potential ease with which fluorinated small molecules relevant to neuroscience drug development can be prepared in a stereochemically comprehensive manner.

Utilization of highly robust and selective crosslinked polymeric ionic liquid-based sorbent coatings in direct-immersion solid-phase microextraction and high-performance liquid chromatography for determining polar organic pollutants in waters

Several crosslinked polymeric ionic liquid (PIL)-based sorbent coatings of different nature were prepared by UV polymerization onto nitinol wires. They were evaluated in a direct-immersion solid-phase microextraction (DI-SPME) method in combination with high-performance liquid chromatography (HPLC) and diode array detection (DAD). The studied PIL coatings contained either vinyl alkyl or vinylbenzyl imidazolium-based (ViCnIm- or ViBCnIm-) IL monomers with different anions, as well as different dicationic IL crosslinkers. The analytical performance of these PIL-based SPME coatings was firstly evaluated for the extraction of a group of 10 different model analytes, including hydrocarbons and phenols, while exhaustively comparing the performance with commercial SPME fibers such as polydimethylsyloxane (PDMS), polyacrylate (PA) and polydimethylsiloxane/divinylbenzene (PDMS/DVB), and using all fibers under optimized conditions. Those fibers exhibiting a high selectivity for polar compounds were selected to carry out an analytical method for a group of 5 alkylphenols, including bisphenol-A (BPA) and nonylphenol (n-NP). Under optimum conditions, average relative recoveries of 108% and inter-day precision values (3 non-consecutive days) lower than 19% were obtained for a spiked level of 10µgL−1. Correlations coefficients for the overall method ranged between 0.990 and 0.999, and limits of detection were down to 1µgL−1. Tap water, river water, and bottled water were analyzed to evaluate matrix effects. Comparison with the PA fiber was also performed in terms of analytical performance. Partition coefficients (logKfs) of the alkylphenols to the SPME coating varied from 1.69 to 2.45 for the most efficient PIL-based fiber, and from 1.58 to 2.30 for the PA fiber. These results agree with those obtained by the normalized calibration slopes, pointing out the affinity of these PILs-based coatings.

Синтез сополимеров бутилметакрилата с использованием компенсационного способа

Butyl methacrylate copolymers with vinyl alkyl ethers and styrene have been obtained by compensate polymerization method. The properties of copolymers have been determined with the use of gel-penetration chromatography, IR- and 1 H NMR-spectroscopy.

Особенности молекулярно-массовых параметров сополимеров алкилметакрилатов с винилалкиловыми эфирами, синтезированных компенсационным методом

Для установления причин образования заметной низкомолекулярной фракции при компенсационной сополимеризации бутилакрилата с винилбутиловым эфиром в кипящем мономере получены новые данные при сравнении процесса из мономерной смеси в ампулах и в кипящем мономере при инициировании динитриломазоизомасляной кислоты, а также компенсационным способом в присутствии триалкилборана. Анализ молекулярно-массовых характеристик свидетельствует о том, что при удалении следов кислорода воздуха при вакуумировании и за счет взаимодействия с триалкилбораном образуется сополимер большей молекулярной массы в сравнении с аналогом, синтезированным в присутствии следов кислорода.

Structure of the copolymers of alkyl methacrylate and vinyl alkyl ethers, novel viscosity modifiers of lubricating oils

Copolymers of vinyl butyl ethers and alkyl methacrylates may find use as resource-saving viscosity modifiers of oils that is due to a new approach to their synthesis, which allows reaching high compositional homogeneity of the polymer chain. The data of 13C NMR spectroscopy were reported which show the structure of alternating copolymers obtained by compensation copolymerization in boiling monomer under the radical initiation.

Influence of synthesis conditions on composition of alkyl (meth)acrylate–vinyl alkyl ether copolimers

Synthesis of methyl methacrylate copolymers with vinyl butyl ether has been carried out from the monomer mixture by compensate polymerization method. Analysis of their composition has shown that, respectively, either a conversion nonuniform copolymer is formed with methyl methacrylate units for the most part, or a copolymer nearing equimolar composition. By the example of monomer couple butyl acrylate–vinyl alkyl ether it has been shown that in order to get the structurally uniform copolymer, it is possible to use both classical radical initiators and binary alkylborane–oxygen initiators.

Viscosity modifiers based on vinyl isobutyl ether copolymers for lubricating oils

The development of viscosity modifiers for lubricating oils is a topical problem from the viewpoint of replacement of imported products. Copolymers based on vinyl isobutyl ether and acrylates were synthesized as viscosity additives for a synthetic oil base, dioctyl sebacate. The composition of the copolymers was studied by IR and NMR spectroscopy, their molecular masses were determined, and the viscosity characteristics of solutions of the copolymers in oils were examined. The resistance of the additives to thermomechanical degradation, determining the operation life of lubricating oils, was evaluated. Copolymers of butyl acrylate with vinyl alkyl ether of branched structure, compared to vinyl butyl ether copolymers, have higher molecular mass and higher thickening power.

Square-planar ruthenium(II) complexes: control of spin state by pincer ligand functionalization.

Functionalization of the PNP pincer ligand backbone allows for a comparison of the dialkyl amido, vinyl alkyl amido, and divinyl amido ruthenium(II) pincer complex series [RuCl{N(CH2 CH2 PtBu2 )2 }], [RuCl{N(CHCHPtBu2 )(CH2 CH2 PtBu2 )}], and [RuCl{N(CHCHPtBu2 )2 }], in which the ruthenium(II) ions are in the extremely rare square-planar coordination geometry. Whereas the dialkylamido complex adopts an electronic singlet (S=0) ground state and energetically low-lying triplet (S=1) state, the vinyl alkyl amido and the divinyl amido complexes exhibit unusual triplet (S=1) ground states as confirmed by experimental and computational examination. However, essentially non-magnetic ground states arise for the two intermediate-spin complexes owing to unusually large zero-field splitting (D>+200 cm(-1) ). The change in ground state electronic configuration is attributed to tailored pincer ligand-to-metal π-donation within the PNP ligand series.

Novel Terpolymers as Pour Point Depressants and Viscosity Modifiers for Lube Oil

Novel terpolymers were synthesized via free radical chain addition polymerization, using different molar ratios of the three used monomers (alkyl acrylate, styrene, and vinyl pyrrolidone). The structures of the prepared terpolymers were confirmed by FTIR, 1H-NMR, and GPC. The prepared terpolymers were evaluated as pour point depressants and viscosity index improvers. It was found that terpolymers prepared from tetradecyl acrylate have a good efficiency than that prepared from hexadecyl acrylate as pour point depressants, and the viscosity index of lube oil increases with increasing the alkyl chain length of the alkyl acrylate used in the preparation of terpolymers.

Fluorine detected 2D NMR experiments for the practical determination of size and sign of homonuclear F–F and heteronuclear C–F multiple bond J-coupling constants in multiple fluorinated compounds

The use of fluorine in molecules obtained from chemical synthesis has become increasingly important within the pharmaceutical and agricultural industry. NMR characterization of these compounds is of great value with respect to their structure elucidation, their screening in metabolomics investigations and binding studies. The favorable NMR properties of the fluorine nucleus make NMR with fluorine detection of great value in this respect. A suite of NMR 2D F–F- and F–C-correlation experiments with fluorine detection was applied to the assignment of resonances, nJCF- and nJFF-couplings as well as the determination of their size and sign. The utilization of this experiment suite was exemplarily demonstrated for a highly fluorinated vinyl alkyl ether. Especially F–C HSQC and J-scaled F–C HMBC experiments allowed determining the size of the J-couplings of this compound. The relative sign of its homo- and heteronuclear couplings was achieved by different combinations of 2D NMR experiments, including non-selective and F2-selective F–C XLOC, F2-selective F–C HMQC, and F–F COSY. The F2-one/two-site selective F–C XLOC versions were found highly useful, as they led to simplifications of the common E.COSY patterns and resulted in a higher confidence level of the assignment by using selective excitation. The combination of F2-one/two-site selective F–C XLOC experiments with a F2-one-site selective F–C HMQC experiment provided the signs of all nJCF- and nJFF-couplings in the vinyl moiety of the test compound. Other combinations of experiments were found useful as well for special purposes when focusing for example on homonuclear couplings a combination of F–F COSY-10 with a F2-one-site selective F–C HMQC could be used. The E.COSY patterns in the spectra demonstrated were analyzed by use of the spin-selective displacement vectors, and in case of the XLOC also by use of the DQ- and ZQ-displacement vectors. The variety of experiments presented shall contribute to facilitate the interpretation of F–C correlations as well as to open alternative pathways for the determination of size and signs of homo- and heteronuclear couplings of multiply fluorinated small molecules.

One-pot atom-economic synthesis of Se-[alkyl(aryl)sulfanylethyl]diselenophosphinates from vinyl sulfides, secondary phosphines and elemental selenium

Alkyl(or aryl)vinyl sulfides react chemo- and regioselectively with secondary phosphines and elemental selenium (1.1:1:2 molar ratio) at 100°C (1,4-dioxane, 1.5 h) to form functionalized Se-[1-(organosulfanyl)ethyl]diselenophosphinates in 83–94% yields.

Synthesis of chemically modified macroreticular resins for the preparation of gold nanoparticles via sorption from aqueous gold solution, and the application of these nanoparticles in catalytic remediation

A new solid-phase support for the preparation of stable gold nanoparticles (AuNPs) was developed, consisting of maleic anhydride and alkyl (C18) vinyl monomer encapsulated into a macroreticular polystyrene resin (Amberlite XAD-2). The maleic anhydride moieties were further modified with either diethylenetriamine (to form the resin RN) or NaOH (to form the resin RCO). The sorption of gold ions from an aqueous gold solution was attempted in a batch process. Gold nanoparticles were immobilized into the pores of both resins by shaking them with aqueous solution containing H[AuCl4] for 1 h at room temperature and then drying them for 24 h at 150 °C to form RN-AuNPs and RCO-AuNPs. The conversion of gold to metallic nanogold was achieved without the use of any external reducing agents. The AuNPs prepared in this manner were characterized by UV–vis spectroscopy and transmission electron microscopy (TEM). The catalytic activity of the prepared nanoparticles in the reduction of 4-nitrophenol was studied, and with the kinetic parameters for this catalyzed reaction were calculated.

Poly(n-Alkyl Itaconate-Co-Vinyl Acetate) as Pour Point Depressants for Lube Oil in Relation to Rheological Flow Properties

In the present work, poly(n-alkyl itaconate-co-vinyl acetate) comb-like polymers were synthesized by radical copolymerization of n-alkyl itaconates of various alkyl chain length and vinyl acetate monomers for use as pour point depressants in lubricant oil. Initially four n-alkyl itaconate monomers were synthesized by esterification of itaconic acid with a series of n-alkyl alcohol, having different alkyl chain length C16/C18/NAFOL 20 + A (Cav = 20)/NAFOL 1822 B (Cav = 22). The copolymerization of these monomers with vinyl acetate was then performed using dibenzoyl peroxide in toluene at 120°C up to high conversion, with molar ratios of 0.25:0.75, 0.50:0.50, and 0.75:0.25 for alkyl itaconate: vinyl acetate. All products were characterized by FTIR, 1H NMR and gel permeation chromatography (GPC). These copolymers were tested in terms of their suitability as pour point depressants and flow improvers for lube oil. The obtained data revealed that the prepared compounds depress the pour point of the lube oil successfully and the additive efficiency on the pour point reduction of the lube oil increases by increasing the concentration of these additives and by decreasing the alkyl chain length of n-alkyl itaconate. The rheological properties of lube oil (with and without copolymer additive) were studied in term of shear rate, shear stress and viscosity. The results indicated that the performance of flow improver was dependent on the copolymer compositions and the size of alkyl chain length of n-alkyl itaconate monomers. Poly(hexadecyl itaconate-co-vinyl acetate) with high content of vinyl acetate showed the best flow improver properties of lube oil. Comparison of morphologies and structures of wax crystals or aggregates in untreated and treated lube oil was also done by micro photographic studies which showed the modification in wax crystal morphology due to additives.

Concise Synthesis of α-(Hydroxymethyl) Alkyl and Aryl Vinyl Ketones

2,4-Diketoesters 2 have first been reported as starting materials for the synthesis of a new class of α-hydroxymethyl-α,β-unsaturated ketones 3. Thus, under heterogeneous liquid–liquid medium in the presence of concentrated aqueous potassium carbonate as a base, both aliphatic and aromatic 2,4-dioxoalkanoates 2 react with aqueous formaldehyde to afford the corresponding ketones 3 in fair to good yields.

Efficient syntheses of C20-carotene and crocetin (descrocetin) esters promoted by an acidic ionic liquid

Efficient syntheses of C20-carotene and crocetin or descrocetin esters from fumaraldehyde bis-dimethylacetal are described. The key steps of these syntheses are the reactions of fumaraldehyde and (2E,4E,6E)-octa-2,4,6-trienedial bis-dimethylacetals with alkyl vinyl or alkyl propenyl ethers promoted by the acidic ionic liquid, [emim][HSO4].