Vinyl Ether Research Articles

Thermophysical study for Binary mixtures of Dimethyl carbonate with Anisole, Butyl vinyl ether, Diisopropyl ether and Dibutyl ether at 303.15, 308.15 and 313.15 K

Ultrasonic velocity, density and viscosity have been determined for the binary compositions of dimethyl carbonate+ butyl vinyl ether, + diisopropyl ether, + anisole and + dibutyl ether at T= 303.15, 308.15 and 313.15 K. The inventive data is applied to assess the excess molar volume VmE, deviation in viscosity Δη and the acoustical parameters namely isentropic compressibility (Ks), free volume (Vf ), free length (Lf ) and internal pressure (πi). The excess or deviation properties are contoured to the Redlich-Kister polynomials and the outcomes are elucidated in terms of molecular interactions present in compositions.

Improved Automated Radiosynthesis of [18F]Dolutegravir: Toward Clinical Applications.

Positron emission tomography imaging using radiolabeled dolutegravir (DTG) is an interesting approach to understand the biodistribution of this antiretroviral drug at HIV-1 sanctuary sites. In the course of clinical translation, we depict herein an improved and pharmaceutically compliant radiosynthesis of [18F]DTG from an original tin precursor. The radiosynthesis was achieved in two steps by copper-mediated radiofluorination, followed by enol ether deprotection using a kit-based AllInOne module. Ready-to-inject [18F]DTG was obtained in 20 ± 5% (n = 12) decay-corrected radiochemical yield within 90 min, representing a 4-fold increase compared to the previously published three-step radiosynthesis. Quality control was carried out with three consecutive [18F]DTG productions according to the current European Pharmacopoeia guidelines, which include pH determination, identity and purity (chemical, radiochemical, and radionuclide) assessments, residual solvent quantification, dosage of lithium, copper, and tin traces, sterility and bacterial endotoxin tests. [18F]DTG (∼2 GBq) was obtained with a molar activity of 59 ± 2 GBq/μmol at the time of injection and was suitable for human applications.

Lymphatic absorption characteristics of eicosapentaenoic acid -enriched phosphoethanolamine plasmalogen and its gastric and intestinal hydrolysates

The aim of this work was to study the lymphatic absorption characteristics of gastric hydrolysates and intestinal hydrolysates of eicosapentaenoic acid-enriched phosphoethanolamine plasmalogen (EPA-pPE) with focusing on the fate of EPA and vinyl ether bonds in the lymph fluid using lymphatic intubation and lipidomics. The results showed that the EPA peak occurred earlier in the gastric (1.5 h) and intestinal (1 h) hydrolysates than in the EPA-pPE group (3 h) with EPA peak content being 2.03 and 1.46 times higher, suggesting pre-hydrolysis contributed to lymphatic absorption. Further, duodenal injection of gastric hydrolysates sn2 EPA-lysoPE produced higher levels of EPA-LPC, PC, PE, and PG. Meanwhile, intestinal hydrolysates free EPA and sn1 lyso-pPE enriched the sn1 + 2 + 3 TG (20:5_20:5_20:5) and increased the vinyl ether bond-containing lipids, such as PE (18:0p_18:0) and PE (18:0p_20:4). This study provides insight into dietary molecular structures of EPA and plasmalogen.

Photocatalytic Synthesis of α-Ketonyl Glycosyl Compounds from Glycosyl Thiols and Silyl Enol Ethers.

The synthesis of C1-ketonyl glycosyl compounds featuring α-selectivity has seldom been reported. We herein devise a glycosyl radical-based approach to facilely access stereoenriched ketonyl glycosyl compounds via an Ir photoredox-catalyzed desulfurative addition to silyl enol ethers, using in situ-generated tetrafluoropyridinyl thioglycosides from glycosyl 1-thiols as radical precursors. This protocol features readily prepared starting materials, mild conditions, excellent functional group tolerance, satisfactory scale-up, and notable amenability to late-stage modification of pharmaceutically relevant complex molecules.

O2-Dependence of reactions of 1,2-dimethoxyethanyl and 1,2-dimethoxyethanylperoxy isomers

Reaction mechanisms of R˙ and ROO˙ radicals derived from low-temperature oxidation of 1,2-dimethoxyethane (CH3O(CH2)2OCH3) were investigated using speciation from multiplexed photoionization mass spectrometry (MPIMS) measurements via Cl-initiated oxidation, in conjunction with electronic structure calculations. The experiments were conducted at 5 bar, from 450 K – 650 K, and O2 concentrations from 1 · 1014 cm–3 – 6 · 1018 cm–3 to probe the effects on competing reaction channels of 1,2-dimethoxyethanyl (R˙) and 1,2-dimethoxyethanylperoxy (ROO˙) isomers. Several species were detected with photoionization spectral fitting – ethene, formaldehyde, methyl vinyl ether, and 2-methoxyacetaldehyde – and, as determined by electronic structure calculations, may form via unimolecular decomposition of 1,2-dimethoxyethanyl or 1,2-dimethoxyethanylperoxy. O2-dependent yield ratios show that the formation pathways for all species undergo a competition between O2-addition and unimolecular decomposition. Adiabatic ionization energies were also calculated and utilized along with exact mass determinations to infer contributions for other species derived exclusively from first- and second-O2-addition, including 1,2-dimethoxyethene, cyclic ethers, and dicarbonyls.In addition to species formed from conventional low-temperature oxidation pathways, an important conclusion is derived from the detection of species produced from an O2-addition step involving ĊH2CH2OCH3 (R˙′), which forms via prompt dissociation of the primary 1,2-dimethoxyethanyl radical (ĊH2O(CH2)2OCH3). Species derived from R˙′ + O2 – 1,3-dioxolane and methyl acetate – were detected at [O2] = 1.2 · 1017 cm–3 and formed on timescales parallel to the main R˙ + O2 reactions. In addition, ion signal at m/z 106 was detected and increased with O2 concentration from which connections are drawn to ketohydroperoxides produced by Q˙′OOH + O2. Detection of such species indicate that β-scission of 1,2-dimethoxyethanyl is sufficiently facile such that timescales of R˙′ + O2 compete with conventional R˙ + O2 pathways.

Fabrication and characterization of poly(methyl vinyl ether maleic anhydride) blended poly(lactic acid) ultrafiltration membrane with upgraded antifouling and separation performance

In this present study, a novel environment-friendly bio-polymeric hybrid ultrafiltration membrane was fabricated by incorporating poly(methyl vinyl ether maleic anhydride) (PMVEAMA) into the poly(lactic acid) (PLA) polymer matrix. The integration of PMVEAMA into PLA significantly altered the membrane's structural morphology, functional characteristics, and filtration performance. As a result, key functional parameters like membrane porosity and water content were increased, which exhibiting the improved hydrophilicity. Furthermore, the molecular weight cut-off of the PLA/PMVEAMA membrane reached up to a maximum of 66.5 KDa with an average pore size of 9.14 nm, subsequently improving the flux of the membrane up to 2.8 times than PLA membrane. The functional capacity of the synthesized membrane was further assessed by testing its ability to filter toxic chlorophenolic compounds. Rejection studies reveal that the PLA/PMVEAMA membrane achieved a rejection efficiency of 44.64 % pentachlorophenol (PCP) and 51.85 % 2,4-dichlorophenol (DCP). Moreover, fouling studies revealed enhanced PCP and DCP flux recovery ratios of 50.94 % and 51.40 %, respectively, with a significant reduction in the flux decline rate. Additionally, the synthesized PLA/PMVEAMA membranes improved stability and regenerative properties up to 12 filtration cycles and antifouling properties highlight its potential to filter chlorophenolic compounds from wastewater.

Vinyl Ether Maleic Acid Polymers: Tunable Polymers for Self-Assembled Lipid Nanodiscs and Environments for Membrane Proteins.

Native lipid bilayer mimetics, including those that use amphiphilic polymers, are important for the effective study of membrane-bound peptides and proteins. Copolymers of vinyl ether monomers and maleic anhydride were developed with controlled molecular weights and hydrophobicity through reversible addition-fragmentation chain-transfer polymerization. After polymerization, the maleic anhydride units can be hydrolyzed, giving dicarboxylates. The vinyl ether and maleic anhydride copolymerized in a close to alternating manner, giving essentially alternating hydrophilic maleic acid units and hydrophobic vinyl ether units along the backbone after hydrolysis. The vinyl ether monomers and maleic acid polymers self-assembled with lipids, giving vinyl ether maleic acid lipid particles (VEMALPs) with tunable sizes controlled by either the vinyl ether hydrophobicity or the polymer molecular weight. These VEMALPs were able to support membrane-bound proteins and peptides, creating a new class of lipid bilayer mimetics.

A Novel Family of Selenazolo[3,2-a]pyridinium Derivatives Based on Annulation Reactions and Comparative Analysis of Antimicrobial Activity of the Selenium and Sulfur Analogs of Chalcogenazolo[3,2-a]pyridiniums

The synthesis of a novel family selenazolo[3,2-a]pyridin-4-ium derivatives in high yields was developed based on the annulation reactions of 2-pyridineselenenyl chloride with unsaturated heteroatom and heterocyclic compounds. The analogous new thiazolo[3,2-a]pyridin-4-ium derivatives were obtained by the annulation reactions of 2-pyridinesulfenyl chloride. The reactions with vinylic ethers and N-vinylimidazole gave 3- substituted selenazolo[3,2-a]- and -[1,3]thiazolopyridin-4-ium derivatives, whereas reactions with allyl alcohol, allyl chloride, allyl bromide, 3-butenoic, 4-pentenoic and 5-hexenoic acids occurred with the opposite regiochemistry, affording 2-substituted [1,3]chalcogenazolo[3,2-a]pyridiniums. The antibacterial activity of the obtained products against gram-positive and gram-negative bacteria was evaluated, and compounds with high activity were discovered. A comparison of the antibacterial properties of [1,3]selenazolo[3,2-a]pyridin-4-ium derivatives with their sulfur analogs shows a higher activity of the selenium compounds.

Dimerization of perfluoropropyl vinyl ether during the pyrolysis of hexafluoropropylene oxide dimer

Dimerization of perfluoropropyl vinyl ether (PPVE) generally reduces its yield and selectivity during the pyrolysis of hexafluoropropylene oxide dimer ((HFPO)2). However, the mechanism of PPVE dimerization is not well understood. In this paper, the PPVE dimer was obtained during the pyrolysis of (HFPO)2. Subsequently, the chemical structure of PPVE dimer was further determined by gas chromatography-mass spectrometry (GC–MS) and nuclear magnetic resonance (NMR). The results showed that the concentration of PPVE dimer rises in proportion to the extended reflux time of PPVE in the reaction system. Based on the experimental phenomenon, a possible generation mechanism of PPVE dimer was then proposed, and the possibility of the generation pathway was further verified in combination with density functional theory (DFT). In addition, to effectively reduce the production of PPVE dimer, crown ethers and quaternary ammonium salts were added to the reaction system as phase transfer catalysts. Among them, the phase transfer catalyst (15-crown-5) was more effective and reduced the PPVE dimer content from 1.34 % to 0.31 %. This work provides an idea to inhibit the dimerization of PPVE and increase the yield and selectivity of PPVE.

Cu-Catalyzed [3+1+1] Cascade Cyclization of O-Acyl Oximes with Sulfur and Silyl Enol Ethers: Rapid Access to Naphthothiazoles.

A three-component cyclization reaction of O-acyl oximes, silyl enol ethers and elemental sulfur has been developed, in which silyl enol ether acts as a C1 synthon to participate in cyclization reaction and build series of 2-aroylnaphthothiazoles and 2-aroylbenzothienothiazoles. The preliminary exploration of the reaction mechanism indicated that this transformation probably proceeded through a radical process, involving S3•- as a key intermediate, enabling subsequent nucleophilic substitution with O-acyl oximes to afford iminosulfur radical, which undergoes 1,3-H shift to yield sulfur-centered radical intermediate. And then this intermediate undergoes radical addition with silyl enol ether, leading to the formation of the titled products through intramolecular cyclization and oxidation. Moreover, the products obtained exhibit favorable fluorescence properties, which indicates their potential application as functional materials.

RAFT polymerization of 2‐hydroxyethyl vinyl ether and dimethyl maleate

<scp>RAFT</scp> polymerization of 2‐hydroxyethyl vinyl ether and dimethyl maleate

The development of high-performance kinetic hydrate inhibitors by introducing N-vinyl caprolactam and vinyl ether homopolymers into PVCap

Low dosage kinetic hydrate inhibitors (KHIs) are a kind of alternative chemical additives to prevent gas hydrate formation in oil & gas production wells and transportation pipelines. In this work, a series of KHIs were experimentally synthesized with N-vinyl caprolactam (N-VCap) and vinyl ether including vinyl ether, vinyl n-butyl ether, vinyl isobutyl ether, triethylene glycol divinyl ether, with the mole ratio ranging from 9:1 to 5:5. The inhibition performance of new-synthesized KHIs on the formation process of methane hydrate were examined and compared with that of commercial N-vinyl caprolactam PVCap. Several ethylenediamine reagents were used as synergists and tested to improve the inhibition capacity of new-synthesized KHIs. The experimental results demonstrate that the introduction of ether groups on PVCap improves the performance of hydrate inhibitors. PVCap-VNBE (N-VCap: vinyl n-butyl ether = 5:5) showed the best inhibition performance for methane hydrate, which could extend the TVO to 1251 min under 6 K subcooling. N,N'-dimethylethylenediamine shows the best synergistic effect for PVCap-VNBE (5:5), and extends the TVO by 2.75 times at 7 K subcooling. Additionally, the relationship between hydrate inhibition performance and interfacial tension of newly-synthesized KHIs under high pressure were studied. It shows that the lower interfacial tension of KHIs would result in longer onset time, exhibiting better inhibition performance.

Multifunctional organic-inorganic hybrid coating for enhanced bronze corrosion protection

Bronze relics with vital historical, artistic, and scientific value, are one of the significant symbolizations of human civilization. However, due to the long burial time and the change in storage conditions, an inevitable and thorny problem arises in preventing the ancient bronze relics from corrosion. Coatings have great potential for metal corrosion protection at present. This study prepared a multifunctional coating consisting of zinc oxide (ZnO), titanium dioxide (TiO2), and fluoroethylene vinyl ether (FEVE) polymer by an organic-inorganic hybrid, which was applied onto the surface of corroded bronze using a self-assembly method and spraying. The rough structure of composite coating resembling that of the mastoid structure found on lotus leaf, effectively prolongs the transmission path of corrosive ions while preventing bronze contact with the corrosive media. Additionally, this study mainly investigated the bronze anti-corrosion mechanism through an electrochemical analysis perspective. Electrochemical tests revealed the lower corrosion current density, and the positive corrosion potential of multifunctional FEVE@ZnO/TiO2 coating immersion in 3.5 wt% NaCl solution. The experimental results demonstrate that the synergistic effect of organic-inorganic significantly enhances corrosion resistance by retarding the corrosion process and providing active protection against corrosion. The multifunctional coating also exhibits exceptional self-cleaning properties and weatherability when without changing the bronze color and appearance. Consequently, this preparation strategy and research approach for constructing a multifunction coating has a great application prospect in the conservation of bronze relics and metal anti-corrosion.

Peds1 deficiency in zebrafish results in myeloid cell apoptosis and exacerbated inflammation

Plasmalogens are glycerophospholipids with a vinyl ether bond that confers unique properties. Recent identification of the gene encoding PEDS1, the desaturase generating the vinyl ether bond, enables evaluation of the role of plasmalogens in health and disease. Here, we report that Peds1-deficient zebrafish larvae display delayed development, increased basal inflammation, normal hematopoietic stem and progenitor cell emergence, and cell-autonomous myeloid cell apoptosis. In a sterile acute inflammation model, Peds1-deficient larvae exhibited impaired inflammation resolution and tissue regeneration, increased interleukin-1β and NF-κB expression, and elevated ROS levels at the wound site. Abnormal immune cell recruitment, neutrophil persistence, and fewer but predominantly pro-inflammatory macrophages were observed. Chronic skin inflammation worsened in Peds1-deficient larvae but was mitigated by exogenous plasmalogen, which also alleviated hyper-susceptibility to bacterial infection, as did pharmacological inhibition of caspase-3 and colony-stimulating factor 3-induced myelopoiesis. Overall, our results highlight an important role for plasmalogens in myeloid cell biology and inflammation.

4]Rhombene: Solution‐Phase Synthesis and Application in Distributed Feedback Lasers With Emission Beyond 830 nm

AbstractGraphene‐like molecules with multiple zigzag edges are emerging as promising gain materials for organic lasers. Their emission wavelengths can vary widely, ranging from visible to near‐infrared (NIR), as the molecular size increases. Specifically, rhombus‐shaped molecular graphenes with two pairs of parallel zigzag edges, known as [n]rhombenes, are excellent candidates for NIR lasers due to their small energy gaps. However, synthesizing large‐size rhombenes with emission beyond 800 nm in solution remains a significant challenge. In this study, we present a straightforward synthesis of an aryl‐substituted [4]rhombene derivative, [4]RB‐Ar, using a method that combines intramolecular radical‐radical coupling with Bi(OTf)3‐mediated cyclization of vinyl ethers. The structure of [4]RB‐Ar was confirmed through X‐ray crystallographic analysis. Bond length analysis and theoretical calculations indicate that aromatic sextets are predominantly localized along the molecule's long axis. Significantly, [4]RB‐Ar demonstrates narrow amplified spontaneous emission at around 834 nm when dispersed in polystyrene thin films. Moreover, solution‐processed distributed feedback lasers employing [4]RB‐Ar as the active gain material display tunable narrow emissions in the range of 830 to 844 nm.

4]Rhombene: Solution-Phase Synthesis and Application in Distributed Feedback Lasers With Emission Beyond 830 nm.

Graphene-like molecules with multiple zigzag edges are emerging as promising gain materials for organic lasers. Their emission wavelengths can vary widely, ranging from visible to near-infrared (NIR), as the molecular size increases. Specifically, rhombus-shaped molecular graphenes with two pairs of parallel zigzag edges, known as [n]rhombenes, are excellent candidates for NIR lasers due to their small energy gaps. However, synthesizing large-size rhombenes with emission beyond 800 nm in solution remains a significant challenge. In this study, we present a straightforward synthesis of an aryl-substituted [4]rhombene derivative, [4]RB-Ar, using a method that combines intramolecular radical-radical coupling with Bi(OTf)3-mediated cyclization of vinyl ethers. The structure of [4]RB-Ar was confirmed through X-ray crystallographic analysis. Bond length analysis and theoretical calculations indicate that aromatic sextets are predominantly localized along the molecule's long axis. Significantly, [4]RB-Ar demonstrates narrow amplified spontaneous emission at around 834 nm when dispersed in polystyrene thin films. Moreover, solution-processed distributed feedback lasers employing [4]RB-Ar as the active gain material display tunable narrow emissions in the range of 830 to 844 nm.

The electrically controlled dimming film of thiol-vinyl ether system with low-voltage and high contrast ratio for smart windows

As a type of smart window, polymer dispersed liquid crystal (PDLC) electrically controlled dimming film can respond to external electrical stimuli to regulate the optical flux of sunlight, reducing energy consumption. Herein, a PDLC film was prepared by systematically studying the functionalities and structural compatibility of vinyl ether and thiol compounds, and the optimal PDLC film possesses a superior contrast ratio (CR) of 196.9. When the film thickness is adjusted to 8 μm, the film saturation voltage is reduced to 6.7 V, still maintaining a high CR of 48.4. The well-designed PDLC films exhibited excellent modulation of light. The temperature difference between PDLC film and bare ITO glass can reach 4 °C under the simulated sunlight test, demonstrating the good thermal insulation performance. This smart films with low power consumption and high CR can meet the demand for active regulation of optical flux on smart windows.

Ready Access to [5,6,5]-Trioxa-spiro and Fused Ketals via Ag-Catalyzed Cascade Annulation of 4-Pentyn-1-ols and Aldehydes.

In this study, we unveil the versatility of 4-pentyn-1-ols as carbonyl surrogates for the unprecedented synthesis of diverse oxygen heterocycles, including [5,6,5]-bis-spiroketals (trioxadispiroketals) and [5,6,5]-furano-spiroketals related to bioactive natural products. These reactions commence with the π-activation-induced intramolecular hydroalkoxylation of 4-pentyn-1-ols, yielding cyclic enol ethers, which undergo subsequent three-component annulation with aldehydes in a [2+2+1+1] fashion, resulting in the formation of [5,6,5]-bis-spiroketals. Notably, the distinctive steric features of alkynyl alcohols, particularly those with a secondary or tertiary alcohol functionality, dictate divergent reaction pathways, leading to the formation of [5,6,5]-furano-spiroketals.

3D Printable Materials Based on Renewable Polymers from Terpene Alcohols and Calcium Carbide

AbstractThe transition to a sustainable future requires the use of waste‐free technologies for production. Potentially, additive technologies can be a promising approach for accessing circular economy due to the precise amount of feeding materials and the absence of molds. However, the initial feeding materials for additive approaches are often based on non–renewable hydrocarbon sources. This work focused on the use of polymers derived from terpene alcohols to develop a filament suitable for 3D printing. Initially, the vinylation of menthol using calcium carbide was optimized and scaled up, then a series of terpenyl–based vinyl ethers were obtained under optimal conditions. The cationic polymerization of vinyl ethers was also scaled up and resulted in 99 % yield of the polymers, which was subsequently subjected to hot extrusion. The initial terpenol was used as an additive to increase polymer flexibility. The addition of menthol (30 wt %) to polyvinyl menthol led to the suitable filament. Using the filament, a series of objects were 3D printed at 125 °C. The material demonstrated good sinterability and adhesion to glass and shrinkage comparable to that of commercial 3D printing filaments. Furthermore, the polymers obtained were used as additives to enhance the adhesion of commercially available filaments.

Streamlining the Synthesis of Pyridones through Oxidative Amination of Cyclopentenones

AbstractHerein we report the development of an oxidative amination process for the streamlined synthesis of pyridones from cyclopentenones. Cyclopentenone building blocks can undergo in situ silyl enol ether formation, followed by the introduction of a nitrogen atom into the carbon skeleton with successive aromatisation to yield pyridones. The reaction sequence is operationally simple, rapid, and carried out in one pot. The reaction proceeds under mild conditions, exhibits broad functional group tolerance, complete regioselectivity, and is well scalable. The developed method provides facile access to the synthesis of 15N‐labelled targets, industrially relevant pyridone products and their derivatives in a fast and efficient way.