Allyl Ethers Research Articles

Thermal decomposition tandem mass spectrometry for rapid detection of tetrabromobisphenol A bis(allyl ether) in soils

Rapidly and sensitively determining trace levels of contaminants with poor ionization in complex matrices is a great challenge for mass spectrometry analysis. In this work, a thermal decomposition tandem mass spectrometry (TD-MS/MS) method is developed for fast detecting tetrabromobisphenol A bis(allyl ether) (TBBPA-BAE) in soils. Typically, TBBPA-BAE solution in a capillary is decomposed and ionized under heating, then sprayed into the mass spectrometer for MS analysis. Upon optimization, one high abundant ion of m/z 542.75 from TBBPA-BAE by debromination is detected during heating process. By collision-induced dissociation, the ion is fragmented to release the characteristic ion of m/z 501.72, which is used as the target quantitative ion. Each test can be finished within 3 min. A linear range of 0.1–100 µg L–1, limit of detection (LOD, S/N = 3, n = 9) of 0.015 μg L–1, and relative standard deviation of 8.6% (c = 0.1 μg L–1, n = 5) are achieved. The fast and sensitive performance of the developed method for analyzing TBBPA-BAE in soils presents its great potential for studying trace levels of TBBPA derivative contaminants.

Drug-release system of microchannel transport used in minimally invasive surgery for hemostasis.

BackgroundSucrose allyl ether (SAE) containing hemostatic drugs and a photoinitiator was established to treat mild postpartum hemorrhage or long-term continuous abnormal uterine bleeding in minimally invasive surgery (MIS) using a photopolymerization method.Methods and resultsReal-time infrared spectroscopy and rheological experiments showed that the SAE monomer with shear-thinning characteristics could polymerize rapidly into a transparent membrane. Cytotoxicity experiments in vitro showed that this system could elicit a long-term hemostatic effect. Tissue adhesion was also evaluated. The photo-stability of four delivered antifibrinolytic drugs (6-aminocaproic acid, ethylenediaminediacetic acid, tranexamic acid and p-(aminomethyl) benzoic acid) was tested by ultraviolet-photolysis experiments and illustrated by time-dependent density functional theory. Sustained-release experiments revealed that the formed film could be used as a drug carrier. Molecular docking and molecular dynamics were done to investigate the binding mechanism between hemostatic drugs as ligands and the human plasminogen kringle-1 (1HPK) as a target.ConclusionIt has been suggested that SAE with tranexamic acid could be a drug-release system of microchannel transport used in MIS. This system could tackle the dilemma of fluidity and adhesion in MIS. The photo-stable tranexamic acid was the most suitable drug according to its satisfactory binding energy, good photo-stability, and sustained release.

Anionic ring-opening copolymerization of styrene oxide with monosubstituted oxiranes: analysis of composition of prepared new copolyether-diols by MALDI-TOF mass spectrometry

Several new random copolyethers of styrene oxide (SO) and other monosubstituted oxirane as comonomer, i.e., propylene oxide (PO), isopropyl glycidyl ether (IPGE) or allyl glycidyl ether (AGE), were synthesized in THF solution at room temperature. As initiator monopotassium salt of dipropylene glycol activated by 18-crown-6 complexing agent was used. Synthesized copolyether-diols were characterized by SEC, 13C NMR and MALDI-TOF techniques. They were unimodal and had Mn = 3500–4600 and relatively low dispersity (Mw/Mn = 1.16–1.18). Low unsaturation of the products resulted from chain transfer reaction to styrene oxide. Composition of SO/PO-diol, SO/IPGE-diol and SO/AGE-diol copolymers was determined by MALDI-TOF mass spectrometry. Homopolymers were not formed during the processes.Graphical abstract

Ultrasensitive separation of methylprednisolone acetate using a photoresponsive molecularly imprinted polymer incorporated polyester dendrimer based on magnetic nanoparticles.

We developed an approach for the use of polyester dendrimer during the imprinting process to raise the number of recognized sites in the polymer matrix and improve its identification ability. Photoresponsive molecularly imprinted polymers were synthesized on modified magnetic nanoparticles involving polyester dendrimer which uses the reactivity between allyl glycidyl ether and acrylic acid for the high-yielding assembly by surface polymerization. The photoresponsive molecularly imprinted polymers were constructed using methylprednisoloneacetate as the template, water-soluble azobenzene involving 5-[(4, 3-(methacryloyloxy) phenyl) diazenyl] dihydroxy aniline as the novel functional monomer, and ethylene glycol dimethacrylate as the cross-linker. Through the evaluation of a series of features of spectroscopic and nano-structural, this sorbent showed excellent selective adsorption, recognition for the template, and provided a highly selective and sensitive strategy for determining the methylprednisoloneacetate in real and pharmaceutical samples. In addition, this sorbent according to good photo-responsive features and specific affinity to methylprednisoloneacetate with high recognition ability, represented higher binding capacity, a more extensive specific area, and faster mass transfer rate than its corresponding surface molecularly imprinted polymer.

Lithium promoted mesoporous manganese oxide catalyzed oxidation of allyl ethers

Herein we report the first example of the catalytic aerobic partial oxidation of allyl ether to its acrylate ester derivative. Many partial oxidations often need an expensive oxidant such as peroxides or other species to drive such reactions. In addition, selective generation of esters using porous catalysts has been elusive. This reaction is catalyzed by a Li ion promoted mesoporous manganese oxide (meso-Mn2O3) under mild conditions with no precious metals, a reusable heterogeneous catalyst, and easy isolation. This process is very attractive for the oxidation of allyl ethers. We report on the catalytic activity, selectivity, and scope of the reaction. In the best cases presented, almost complete conversion of allyl ether with near complete chemo-selectivity towards acrylate ester derivatives is observed. Based on results from controlled experiments, we propose a possible reaction mechanism for the case in which N-hydroxyphthalimide (NHPI) is used in combination with trichloroacetonitrile (CCl3CN).

Preparation and flame retardancy of castor oil based UV-cured flame retardant coating containing P/Si/S on wood surface

In this paper, a multifunctional castor oil based bio-mercaptan (abbrev. COSH) was synthesized by esterification between castor oil (abbrev. CO) and 3-mercaptopropionic acid (MPA). In addition, [(6-Oxido-6H-dibenz [c,e][1,2] oxaphosphorin-6-yl) methyl] butanedioic acid (DDP) and allyl glycidyl ether (AGE) were used to synthesize the organic phosphorus flame retardant containing a double bond of allyl ether DDP-AGE (abbrev. DA) via a ring-opening reaction. The synergistic flame-retardant UV-cured coating containing phosphorus (P), silicon (Si) and sulfur (S) was prepared on wood surface with varying molar content of COSH, DA and 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane (TTC) via the thiol-ene click reaction. The results show that when the molar ratio of COSH, DA and TTC is 5: 3: 3, the UV-cured coated wood samples pass the vertical UL-94 V-0 rating; the limiting oxygen index (LOI) value can reach 27.52%; the second peak of heat release rate (P2HRR) and the second smoke production rate peak (P2SPR) of the coated wood samples can be effectively suppressed, while the total heat release (THR) of 16.99 MJ/m2 is much lower than other samples and the total smoke production (TSP) is equivalent to that of uncoated wood sample; the final char residue rate can reach 14.41% during the cone calorimetry (CONE) tests. Moreover, the thermogravimetric analysis (TGA) demonstrates that COSH promotes the degradation of films at a lower temperature, while it reduces the maximum degradation rate and delays the decomposition process simultaneously. Besides, the scanning electron microscope (SEM) shows that the coated wood internal tracheid basic skeleton remains basically intact and the char layer tends to exhibit a more compact morphology after the CONE tests if the wood is coated following the molar ratio of COSH, DA and TTC of 5: 3: 3. Energy dispersive spectrometer (EDS) was used to compare the content of C, O, N, P, Si and S of the char layers formed by the coatings on the surface of coated wood samples after CONE tests, which addresses the synergistic flame retardance of P, S and P, Si.

Anti-Markovnikov terminal and gem-olefin hydrosilylation using a κ4-diimine nickel catalyst: selectivity for alkene hydrosilylation over ether C-O bond cleavage.

The phosphine-substituted α-diimine Ni precursor, (Ph2PPrDI)Ni, has been found to catalyze alkene hydrosilylation in the presence of Ph2SiH2 with turnover frequencies of up to 124 h-1 at 25 °C (990 h-1 at 60 °C). Moreover, the selective hydrosilylation of allylic and vinylic ethers has been demonstrated, even though (Ph2PPrDI)Ni is known to catalyze allyl ester C-O bond hydrosilylation. At 70 °C, this catalyst has been found to mediate the hydrosilylation of ten different gem-olefins, with turnover numbers of up to 740 under neat conditions. Prior and current mechanistic observations suggest that alkene hydrosilylation takes place though a Chalk-Harrod mechanism following phosphine donor dissociation.

Current-use halogenated and organophosphorous flame retardants: A review of their presence in Arctic ecosystems

Abstract Since the ban of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD), other flame retardants may be increasingly used. Thirty-one current-use halogenated (HFRs) and 24 organophosphorous flame retardants (PFRs) have been sought in Arctic ecosystems so far. Air measurements provide evidence of long-range atmospheric transport for the majority of these compounds, with much higher concentrations for PFRs than for HFRs. Some HFRs, i.e. bis(2-ethylhexyl)-tetrabromophthalate (BEH-TEBP), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) and hexabromobenzene (HBBz), had air concentrations comparable to those of PBDEs in some studies. Complementary data for seawater and ice indicate dry deposition of HFRs, while net volatilization from seawater was observed for some PFRs. Studies in the marine environment indicate a wide presence of HFRs in marine biota, but generally at low levels, i.e. typically lower than those of PBDEs. Exceptions exist, namely 2,4,6-tribromophenyl 2,3-dibromopropyl ether (TBP-DBPE) and decabromodiphenyl ethane (DBDPE), which were found in concentrations comparable to PBDEs in some species. The same was the case for 2,4,6-tribromophenyl allyl ether (TBP-AE) in a study from the terrestrial environment. PFRs generally had low concentrations in biota, probably due to metabolic transformation of PFR triesters, as suggested by in vitro studies. Elevated PFR concentrations occurred in some individuals, generally indicating a larger variability of PFRs in biota than found for HFRs. The commercially important tetrabromobisphenol A (TBBPA) was only detected sporadically, and only in abiotic matrices.

Новый эффективный способ получения ароматических аллиловых и пропаргиловых эфиров

Новый эффективный способ получения ароматических аллиловых и пропаргиловых эфиров

Tandem arylation and regioselective allylic etherification of 2,3-allenol via Pd/B cooperative catalysis.

An efficient method for the construction of arylated allylic ethers was developed via three-component tandem arylation and allylic etherification of 2,3-allenol with aryl iodides and alcohols. In the cooperative catalytic system of a palladium complex and triethylborane, the process allows rapid access to functionalized 1-arylvinylated 1,2-diol derivatives in good to high yields with complete branch-selectivities. The synthetic utility of the present process was demonstrated by the late-stage functionalization of a drug molecule, the gram-scale synthesis and the elaboration of the products.

Asymmetric synthesis of multifunctional aryl allyl ethers by nucleophilic catalysis.

Asymmetric allylic substitution of Morita–Baylis–Hillman (MBH) carbonates with less-nucleophilic phenols mediated by nucleophilic amine catalysis was successfully developed. A variety of substituted aryl allyl ethers were afforded with moderate to high yields with excellent enantioselectivities. The chiral MBH alcohol could be easily accessed from the corresponding aryl allyl ether.

Оптимизация процесса радикальной соолигомеризации стирола с аллиловым эфиром n­изопропенилфенола

Оптимизация процесса радикальной соолигомеризации стирола с аллиловым эфиром n­изопропенилфенола

Allyl type monomers for hard surface coating protection

Based on the unsaturated derivatives of polyfluoroalkanols chemical products are used to protect solid and fibrous materials surface from the effects of water, oils and other pollutants. A method for obtaining allyl ethers of polyfluoroalkanols (polyfluoroalkoxypropenes) is based on the Williamson ether reaction. This method is a heterophase process. The use of solvents to improve mass transfer requires complementary measures to ensure industrial and environmental safety. It is more preferable to obtain the target ethers in water with PTC. A series of experiments using different chain length polyfluoroalkanols was studied by GLC. Kovats retention indexes of the target ethers were determined. It was found that in the case of lower homologues (CF3CH2OH, (CF3)2CHOH, HCF2CF2CH2OH), the addition of 5-15 vol.% 1,4-dioxane as a solubilizer provides a high yield of products. The application of PTC (tetrabutylammonium bromide) is indispensable for using polyfluoroalkanols with a longer carbon chain (C≥5). PTC invariably provides the almost complete conversion of polyfluoroalkanols. The decomposition process of TBAB becomes noticeable (GLC method) upon completion of the main reaction. Polyfluoroalkoxypropenes form azeotrope with water, which can be used in the work up process.

Asymmetric [2,3]-Wittig Rearrangement: Synthesis of Homoallylic, Allenylic, and Enynyl α-Benzyl Alcohols.

A highly stereoselective [2,3]-Wittig rearrangement of allylic and propargylic ethers controlled by a chiral sulfoxide moiety is presented. The activation provided by the sulfoxide at the remote ortho position allows the rearrangement of less-activated and unexplored benzylic carbanions. Thus, this general methodology gives access to the asymmetric synthesis of homoallylic, enynyl, and allenylic α-benzyl alcohol derivatives.

Ring-closing-metathesis-based synthesis of annellated coumarins from 8-allylcoumarins.

8-Allylcoumarins are conveniently accessible through a microwave-promoted tandem Claisen rearrangement/Wittig olefination/cyclization sequence. They serve as a versatile platform for the annellation of five- to seven-membered rings using ring-closing olefin metathesis (RCM). Furano-, pyrano-, oxepino- and azepinocoumarins were synthesized from the same set of precursors using Ru-catalyzed double bond isomerizations and RCM in a defined order. One class of products, pyrano[2,3-f]chromene-2,8-diones, were inaccessible through direct RCM of an acrylate, but became available from the analogous allyl ether via an assisted tandem catalytic RCM/allylic oxidation sequence.

The effect of the concentration of non-ionic collector — allyl ether amylxanthate acid on flotation of copper-molybdenum ores

The effect of the concentration of non-ionic collector — allyl ether amylxanthate acid on flotation of copper-molybdenum ores

Impact of molecular structure and composition of polycarboxylate comb polymers on the flow properties of alkali-activated slag

This study is giving new insights on the behavior of polycarboxylate ether (PCE) polymers in alkali-activated slag (AAS). Two systems have been considered: sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) activated slag. A broad range of MPEG (methacrylate), APEG (allyl ether) and IPEG (isoprenol ether) based PCEs exhibiting different molecular structures have been synthesized and tested. First, solubility of the PCE polymers was measured in both alkaline systems. The influence of PCE molecular parameters (side chain length, charge density, chemical composition) was elucidated. Furthermore, impact of the PCEs on the paste rheology was probed via mini-slump experiments. It was found that sufficient solubility of the PCE polymer presents the key property to achieve fluidity. In the NaOH activated system, an allylether maleic anhydride-based PCE possessing short side chain and high solubility produced excellent dispersion. Unfortunately, no PCE polymers which were soluble and efficient in the Na2CO3 activated system were found.

Synthesis of Alkyl 4-Ethyn(en)yl-6-methyl-1,3-dioxane-5-carboxylates

Condensations of chloromethyl propargyl(allyl) ethers with alkyl 3-oxobutanoates in the presence of pyridine gave substituted 1,3-dioxanes.

Iridium-Catalyzed Highly Regioselective and Diastereoselective Allylic Etherification To Access cis-2,6-Disubstituted Dihydropyridinones.

A highly regio- and diastereoselective method to access cis-2,6-disubstituted dihydropyridinones under mild conditions by an iridium-catalyzed allylic etherification is reported. cis-2,6-Disubstituted dihydropyridinones are important precursors for the de novo synthesis of the corresponding piperidine alkaloids and iminosugars. This strategy features a broad substrate scope, high yields, and excellent regio- and diastereoselectivities. A π-allyl-Ir intermediate is involved in the mechanism. The strong A1,3-strain from the tosyl group may also favor the formation of cis-products in this transformation.

Dynamic Sulfur Bonds Initiate Polymerization of Vinyl and Allyl Ethers at Mild Temperatures

Elemental sulfur (S8) is produced in abundance during petroleum refinement, generating millions of tons of waste. Inverse vulcanization utilizes this waste as a feedstock to create new materials. Heating S8 above 159 °C initiates ring-opening, forming radicals that react with difunctional monomers to create polysulfides. High temperature requirements limit the types of monomers that can be incorporated by inverse vulcanization. However, cleaving the linear sulfur chains present in the polysulfides requires less energy. Here, poly(S–divinylbenzene) with varied sulfur contents has been synthesized to act as a prepolymer capable of radical formation at much lower temperatures (90 °C). Dynamic sulfur bonds initiate polymerization with a family of vinylic and allylic ethers. Terpolymers were characterized by NMR spectroscopy, gel permeation chromatography, and differential scanning calorimetry to examine the impact on structure and physical properties. This method expands on inverse vulcanized polymers to crea...