Ether: A mobile, very volatile, highly flammable liquid used as an inhalation anesthetic and as a solvent for waxes, fats, oils, perfumes, alkaloids, and gums. It is mildly irritating to skin and mucous membranes.EthersEthyl EthersHalogenated Diphenyl Ethers: Compounds that contain two halogenated benzene rings linked via an OXYGEN atom. Many polybrominated diphenyl ethers are used as FLAME RETARDANTS.Phenyl Ethers: Ethers that are linked to a benzene ring structure.Crown Ethers: Macrocyclic polyethers with the repeating unit of (-CH2-CH2-O)n where n is greater than 2 and some oxygens may be replaced by nitrogen, sulfur or phosphorus. These compounds are useful for coordinating CATIONS. The nomenclature uses a prefix to indicate the size of the ring and a suffix for the number of heteroatoms.Phospholipid Ethers: Phospholipids which have an alcohol moiety in ethereal linkage with a saturated or unsaturated aliphatic alcohol. They are usually derivatives of phosphoglycerols or phosphatidates. The other two alcohol groups of the glycerol backbone are usually in ester linkage. These compounds are widely distributed in animal tissues.Glyceryl Ethers: Compounds in which one or more of the three hydroxyl groups of glycerol are in ethereal linkage with a saturated or unsaturated aliphatic alcohol; one or two of the hydroxyl groups of glycerol may be esterified. These compounds have been found in various animal tissue.Methyl Ethers: A group of compounds that contain the general formula R-OCH3.Ethylene Glycols: An ethylene compound with two hydroxy groups (-OH) located on adjacent carbons. They are viscous and colorless liquids. Some are used as anesthetics or hypnotics. However, the class is best known for their use as a coolant or antifreeze.Polybrominated Biphenyls: Biphenyl compounds which are extensively brominated. Many of these compounds are toxic environmental pollutants.Flame Retardants: Materials applied to fabrics, bedding, furniture, plastics, etc. to retard their burning; many may leach out and cause allergies or other harm.Bis(Chloromethyl) Ether: A substance that is an irritant to the eyes and respiratory tract and may be carcinogenic.Ethers, Cyclic: Compounds of the general formula R-O-R arranged in a ring or crown formation.Plasmalogens: GLYCEROPHOSPHOLIPIDS in which one of the two acyl chains is attached to glycerol with an ether alkenyl linkage instead of an ester as with the other glycerophospholipids.tert-Butyl AlcoholVinyl CompoundsHydrocarbons, BrominatedMolecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)AcetalsChromatography, Gas: Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.Cyclization: Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Gas Chromatography-Mass Spectrometry: A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.Gasoline: Volative flammable fuel (liquid hydrocarbons) derived from crude petroleum by processes such as distillation reforming, polymerization, etc.Alkenes: Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)Chromatography, Thin Layer: Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Boranes: The collective name for the boron hydrides, which are analogous to the alkanes and silanes. Numerous boranes are known. Some have high calorific values and are used in high-energy fuels. (From Grant & Hackh's Chemical Dictionary, 5th ed)Solvents: Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)Environmental Pollutants: Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.Glycerides: GLYCEROL esterified with FATTY ACIDS.Glycols: A generic grouping for dihydric alcohols with the hydroxy groups (-OH) located on different carbon atoms. They are viscous liquids with high boiling points for their molecular weights.Methoxyflurane: An inhalation anesthetic. Currently, methoxyflurane is rarely used for surgical, obstetric, or dental anesthesia. If so employed, it should be administered with NITROUS OXIDE to achieve a relatively light level of anesthesia, and a neuromuscular blocking agent given concurrently to obtain the desired degree of muscular relaxation. (From AMA Drug Evaluations Annual, 1994, p180)EstersEpoxy Compounds: Organic compounds that include a cyclic ether with three ring atoms in their structure. They are commonly used as precursors for POLYMERS such as EPOXY RESINS.Alcohols: Alkyl compounds containing a hydroxyl group. They are classified according to relation of the carbon atom: primary alcohols, R-CH2OH; secondary alcohols, R2-CHOH; tertiary alcohols, R3-COH. (From Grant & Hackh's Chemical Dictionary, 5th ed)Furans: Compounds with a 5-membered ring of four carbons and an oxygen. They are aromatic heterocycles. The reduced form is tetrahydrofuran.PropaneFatty Alcohols: Usually high-molecular-weight, straight-chain primary alcohols, but can also range from as few as 4 carbons, derived from natural fats and oils, including lauryl, stearyl, oleyl, and linoleyl alcohols. They are used in pharmaceuticals, cosmetics, detergents, plastics, and lube oils and in textile manufacture. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Pyran Copolymer: Copolymer of divinyl ether and maleic anhydride that acts as an immunostimulant with antineoplastic and anti-infective properties. It is used in combination with other antineoplastic agents.Silanes: Compounds similar to hydrocarbons in which a tetravalent silicon atom replaces the carbon atom. They are very reactive, ignite in air, and form useful derivatives.Dihematoporphyrin Ether: The purified component of HEMATOPORPHYRIN DERIVATIVE, it consists of a mixture of oligomeric porphyrins. It is used in photodynamic therapy (HEMATOPORPHYRIN PHOTORADIATION); to treat malignant lesions with visible light and experimentally as an antiviral agent. It is the first drug to be approved in the use of PHOTODYNAMIC THERAPY in the United States.Biodegradation, Environmental: Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.Alkanes: The generic name for the group of aliphatic hydrocarbons Cn-H2n+2. They are denoted by the suffix -ane. (Grant & Hackh's Chemical Dictionary, 5th ed)Chloroform: A commonly used laboratory solvent. It was previously used as an anesthetic, but was banned from use in the U.S. due to its suspected carcinogenicity.KetonesOximes: Compounds that contain the radical R2C=N.OH derived from condensation of ALDEHYDES or KETONES with HYDROXYLAMINE. Members of this group are CHOLINESTERASE REACTIVATORS.Propylene Glycols: Derivatives of propylene glycol (1,2-propanediol). They are used as humectants and solvents in pharmaceutical preparations.Guaifenesin: An expectorant that also has some muscle relaxing action. It is used in many cough preparations.ButanesChemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Plant Extracts: Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.Cissus: A plant genus of the family VITACEAE. Cissus rufescence gum is considered comparable to TRAGACANTH.Chondrodysplasia Punctata, Rhizomelic: An autosomal recessive form of CHONDRODYSPLASIA PUNCTATA characterized by defective plasmalogen biosynthesis and impaired peroxisomes. Patients have shortened proximal limbs and severely disturbed endochondral bone formation. The metabolic defects associated with the impaired peroxisomes are present only in the rhizomelic form of chondrodysplasia punctata. (From Scriver et al, Metabolic Basis of Inherited Disease, 6th ed, p1497)Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Hydrocarbons, HalogenatedPhospholipids: Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.Anesthetics: Agents that are capable of inducing a total or partial loss of sensation, especially tactile sensation and pain. They may act to induce general ANESTHESIA, in which an unconscious state is achieved, or may act locally to induce numbness or lack of sensation at a targeted site.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Egtazic Acid: A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.Surface-Active Agents: Agents that modify interfacial tension of water; usually substances that have one lipophilic and one hydrophilic group in the molecule; includes soaps, detergents, emulsifiers, dispersing and wetting agents, and several groups of antiseptics.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Bromine: A halogen with the atomic symbol Br, atomic number 36, and atomic weight 79.904. It is a volatile reddish-brown liquid that gives off suffocating vapors, is corrosive to the skin, and may cause severe gastroenteritis if ingested.Acetates: Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.Polyethylene Glycols: Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.Kinetics: The rate dynamics in chemical or physical systems.Teratogens: An agent that causes the production of physical defects in the developing embryo.Allyl CompoundsAgrocybe: A genus of saprobic mushrooms in the family Bolbitiaceae that grow in grass, dung, garden mulch, or in woods.CyclopropanesAldehydes: Organic compounds containing a carbonyl group in the form -CHO.Alkynes: Hydrocarbons with at least one triple bond in the linear portion, of the general formula Cn-H2n-2.Polychlorinated Biphenyls: Industrial products consisting of a mixture of chlorinated biphenyl congeners and isomers. These compounds are highly lipophilic and tend to accumulate in fat stores of animals. Many of these compounds are considered toxic and potential environmental pollutants.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Hematoporphyrins: Iron-free derivatives of heme with 4 methyl groups, 2 hydroxyethyl groups and 2 propionic acid groups attached to the pyrrole rings. Some of these PHOTOSENSITIZING AGENTS are used in the PHOTOTHERAPY of malignant NEOPLASMS.Phosphines: Inorganic or organic compounds derived from phosphine (PH3) by the replacement of H atoms. (From Grant & Hackh's Chemical Dictionary, 5th ed)Phenols: Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.Organosilicon Compounds: Organic compounds that contain silicon as an integral part of the molecule.Indicators and Reagents: Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)Lipids: A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)Methanol: A colorless, flammable liquid used in the manufacture of FORMALDEHYDE and ACETIC ACID, in chemical synthesis, antifreeze, and as a solvent. Ingestion of methanol is toxic and may cause blindness.

UV irradiation of polycyclic aromatic hydrocarbons in ices: production of alcohols, quinones, and ethers. (1/902)

Polycyclic aromatic hydrocarbons (PAHs) in water ice were exposed to ultraviolet (UV) radiation under astrophysical conditions, and the products were analyzed by infrared spectroscopy and mass spectrometry. Peripheral carbon atoms were oxidized, producing aromatic alcohols, ketones, and ethers, and reduced, producing partially hydrogenated aromatic hydrocarbons, molecules that account for the interstellar 3.4-micrometer emission feature. These classes of compounds are all present in carbonaceous meteorites. Hydrogen and deuterium atoms exchange readily between the PAHs and the ice, which may explain the deuterium enrichments found in certain meteoritic molecules. This work has important implications for extraterrestrial organics in biogenesis.  (+info)

Divinyl ether fatty acid synthesis in late blight-diseased potato leaves. (2/902)

We conducted a study of the patterns and dynamics of oxidized fatty acid derivatives (oxylipins) in potato leaves infected with the late-blight pathogen Phytophthora infestans. Two 18-carbon divinyl ether fatty acids, colneleic acid and colnelenic acid, accumulated during disease development. To date, there are no reports that such compounds have been detected in higher plants. The divinyl ether fatty acids accumulate more rapidly in potato cultivar Matilda (a cultivar with increased resistance to late blight) than in cultivar Bintje, a susceptible cultivar. Colnelenic acid reached levels of up to approximately 24 nmol (7 microgram) per g fresh weight of tissue in infected leaves. By contrast, levels of members of the jasmonic acid family did not change significantly during pathogenesis. The divinyl ethers also accumulated during the incompatible interaction of tobacco with tobacco mosaic virus. Colneleic and colnelenic acids were found to be inhibitory to P. infestans, suggesting a function in plant defense for divinyl ethers, which are unstable compounds rarely encountered in biological systems.  (+info)

Adaptation of bulk constitutive equations to insoluble monolayer collapse at the air-water interface. (3/902)

A constitutive equation based on stress-strain models of bulk solids was adapted to relate the surface pressure, compression rate, and temperature of an insoluble monolayer of monodendrons during collapse at the air-water interface. A power law relation between compression rate and surface pressure and an Arrhenius temperature dependence of the steady-state creep rate were observed in data from compression rate and creep experiments in the collapse region. These relations were combined into a single constitutive equation to calculate the temperature dependence of the collapse pressure with a maximum error of 5 percent for temperatures ranging from 10 degrees to 25 degrees C.  (+info)

Phospholipid metabolism in ehrlich ascites tumor cells. II. Turnover rate of ether phospholipids. (4/902)

1. Radioactive precursors of phospholipids, i.e., 32Pi, [1-14C]glycerol, [2-3H]glycerol, and [1-14C]acetate, were individually injected into the peritoneal cavity of mice bearing Ehrlich ascites tumor cells and the rates of incorporation were estimated. 2. Although [2-3H]glycerol was not practically incorporated into ether phospholipids, the other three radioactive precursors were incorporated into diacyl, 1-O-alkenyl-2-acryl-, and 1-O-alkyl-2-acryl-GPE (GPC). 3. In the experiments on 32Pi or [1-14C]acetate incorporation, 1-O-alkyl compounds in the ethanolamine phosphoglyceride fraction showed high specific activities in comparison with 1-acyl compounds. In the case of [1-14C]glycerol incorporation, a high rate of incorporation into 1-O-alkyl compounds was not found. In the choline phosphoglyceride fraction, a high rate of incorporation of the above precursors into 1-O-alkyl compounds was not observed. 4. The specific activities of 1-O-alkenyl compounds were fairly low compared with those of 1-acyl- and 1-O-acyl- and 1-O-alkyl compounds throughout the incorporation experiments with [1-14C]glycerol and [1-14C]acetate, but in 32Pi incorporation, 1-O-alkenyl compounds showed higher specific activities than 1-acyl compounds in ethanolamine phosphoglyceride, suggesting an exchange reaction of the phosphorylethanolamine moiety. 5. From the above findings, it appears that alkyl ether phospholipids of ethanolamine from may have a significant role in ascites tumor cells, based on their rapid turnover.  (+info)

The class B, type I scavenger receptor promotes the selective uptake of high density lipoprotein cholesterol ethers into caveolae. (5/902)

The uptake of cholesterol esters from high density lipoproteins (HDLs) is characterized by the initial movement of cholesterol esters into a reversible plasma membrane pool. Cholesterol esters are subsequently internalized to a nonreversible pool. Unlike the uptake of cholesterol from low density lipoproteins, cholesterol ester uptake from HDL does not involve the internalization and degradation of the particle and is therefore termed selective. The class B, type I scavenger receptor (SR-BI) has been identified as an HDL receptor and shown to mediate selective cholesterol ester uptake. SR-BI is localized to cholesterol- and sphingomyelin-rich microdomains called caveolae. Caveolae are directly involved in cholesterol trafficking. Therefore, we tested the hypothesis that caveolae are acceptors for HDL-derived cholesterol ether (CE). Our studies demonstrate that in Chinese hamster ovary cells expressing SR-BI, >80% of the plasma membrane associated CE is present in caveolae after 7.5 min of selective cholesterol ether uptake. We also show that excess, unlabeled HDL can extract the radiolabeled CE from caveolae, demonstrating that caveolae constitute a reversible plasma membrane pool of CE. Furthermore, 50% of the caveolae-associated CE can be chased into a nonreversible pool. We conclude that caveolae are acceptors for HDL-derived cholesterol ethers, and that caveolae constitute a reversible, plasma membrane pool of cholesterol ethers.  (+info)

The movement of an unemulsified oil test meal and aqueous- and oil-phase markers through the intestine of normal and bile-diverted rats. (6/902)

An unemulsified oil test meal containing aqueous- and oil-phase markers (PEG and 3-H labelled triether) was fed to control and bile fustula rats. PEG moved ahead of the lipid phase in all groups, and was of limited value as a marker for the test meal. Triether was an excellent marker for studies of gastric emptying. An unexpectedly high correlation was seen between the triether and the test meal and its digestion products in the intestine. The results suggest that triether is a valid marker for following the movement of lipid through the bowel under the conditions of this study. Triether/fat ratios indicated that fat absorption occurred largely from the upper small bowel in control animals and from the lower small bowel in the absence of bile. Bile diversion resulted in more rapid gastric emptying initially, but very slow gastric emptying of the last part of the oil test meal. Intestinal transit of test meal or either marker was not significantly affected by bile diversion. No evidence for a direct effect of bile diversion on gastrointestinal motility was found.  (+info)

Identification of selective mechanism-based inactivators of cytochromes P-450 2B4 and 2B5, and determination of the molecular basis for differential susceptibility. (7/902)

Rabbit cytochromes P-450 (P-450) 2B4 and 2B5 differ by only 12 amino acid residues yet they exhibit unique steroid hydroxylation profiles. Previous studies have led to the identification of active site residues that are determinants of these specificities. In this study, mechanism-based inactivators were identified that discriminate between the closely related 2B4 and 2B5 enzymes. A previously characterized inhibitor, 2-ethynylnaphthalene (2EN), was found to be selective for 2B4 inactivation. As inhibitor metabolism and the partition ratio affect susceptibility, molecular dynamics simulations were performed to assess the stability of the productive binding orientation of 2EN within 2B4 and 2B5 three-dimensional models. Although 2EN was stable within the 2B4 model, it exhibited substantial movement away from the heme moiety in the 2B5 model. However, heterologously expressed 2B5 was found to catalyze the oxidation of 2EN to the stable product 2-naphthylacetic acid. Thus, the increased mobility of 2EN may result in reduced susceptibility of 2B5 by increasing the probability that the reactive ketene intermediate hydrolyzes with water instead of reacting with active site residues. Another compound, 1-adamantyl propargyl ether (1APE), selectively inactivated 2B5. The structural basis for 2EN and 1APE susceptibility was assessed using active site mutants. Interconversion of 2EN susceptibility was observed for 2B4 or 2B5 mutants containing a single alteration at residue 363. Single substitutions in 2B4 also conferred susceptibility to 1APE; however, multiple alterations were required to reduce the susceptibility of 2B5. These alterations may influence inhibitor susceptibility by affecting the stability of the productive binding orientation.  (+info)

Carrier-mediated hepatic uptake of peptidic endothelin antagonists in rats. (8/902)

The endothelin antagonist BQ-123, an anionic cyclopentapeptide, is taken up by rat hepatocytes through active transport systems. Here, we have examined the hepatocellular uptake mechanism for several BQ-123 derivatives with anionic charges using isolated rat hepatocytes. BQ-485, a linear peptide, BQ-518, a cyclic peptide, and compound A, a cyclic peptide with a cationic moiety, were taken up by hepatocytes in a concentration-dependent manner. The uptake of BQ-485 was most efficient, whereas compound A showed comparable uptake with BQ-123. The uptake of these peptides was Na(+)- and energy-dependent, suggesting that active transport mechanisms are involved in their uptake into hepatocytes. BQ-485, BQ-518, and compound A can almost completely inhibit both the Na(+)-dependent and -independent uptake of [(3)H]BQ-123, with inhibition constants (K(i)) that are comparable to the Michaelis-Menten constants (K(m)) for their Na(+)-dependent and -independent uptake, respectively. Inhibition by BQ-485 was competitive, and the uptake of BQ-485 can be inhibited by BQ-123, with K(i) values that are comparable with the K(m) values for BQ-123 uptake. The uptake of BQ-123 by COS-7 cells transfected with either Na(+)-dependent taurocholate-cotransporting polypeptide (Ntcp) or Na(+)-independent basolateral organic anion-transporting polypeptide (oatp1) was minimal. Thus, these three peptides share the transporters that also recognize BQ-123 but appear to differ from Ntcp and oatp1.  (+info)

  • The Mukaiyama aldol addition is an organic reaction and a type of aldol reaction between a silyl enol ether and an aldehyde or formate. (
  • An iron‐catalyzed coupling reaction of O ‐acyloximes and O ‐benzoyl amidoximes with silyl enol ethers is reported. (
  • Silyl enol ethers are common reagents in organic synthesis as illustrated by the Mukaiyama aldol reaction: Vinyl acetate is an enol ester that is made on an industrial scale. (
  • A particular intriguing example involves a one‐pot synthesis of silyl enol ether 1j by means of a Diels−Alder reaction, subsequent nonaflation and a Heck reaction with tert‐butyl acrylate, furnishing the highly functionalised 1,3‐diene 30 in good overall yield. (
  • Enol silyl ethers and their analogs are one of the most versatile substrate classes and enjoy widespread applications in organic synthesis (Fig. (
  • Yet there are no reports of broadly applicable, catalytic methods for the synthesis of chiral silyl enol ethers carrying latent functionalities useful for synthetic operations beyond the many possible reactions of the silyl enol ether moiety itself. (
  • Electrooxidative Coupling of Aromatics and Silyl Enol Ethers: Application to the Synthesis of Annulated Aromatics Jeffrey B. Sperry* Mand Dennis L. Wright Dartmouth College Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755 The preparation of annulated furan and benzene systems from a two-step conjugate addition, electrochemical annulation sequence has been … The use of silyl enol ethers as an enolate equivalent in Lewis acid-catalyzed aldol additions. (
  • Enol silyl ethers can be cleaved with nucleophiles such as MeLi, LiNH 2 or R 4 N + F-to give reactive enolates. (
  • This fact sheet answers the most frequently asked health questions (FAQs) about polybrominated diphenyl ethers (PBDEs). (
  • Polybrominated diphenyl ethers (PBDEs) are man-made chemicals found in plastics used in a variety of consumer products to make them difficult to burn. (
  • Polybrominated diphenyl ethers (PBDEs) are flame-retardant chemicals that were added to plastics and foam products to make them difficult to burn. (
  • Rats and mice that ate food with There are tests that can detect PBDEs in blood, body fat, decabromodiphenyl ether (one type of PBDE) throughout and breast milk. (
  • Blood tests are the atoms than decabromodiphenyl ether are listed by the EPA as easiest and safest for detecting recent exposures to large not classifiable as to human carcinogenicity due to the lack amounts of PBDEs. (
  • Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants , first produced commercially in the 1970s. (
  • Polybrominated diphenyl ethers (PBDEs) are structurally similar to known human toxicants polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs), dioxins and furans . (
  • Polybrominated diphenyl ethers (PBDEs), a group of flame retardants, and perfluoroalkyl substances (PFASs) were analysed in serum samples of pregnant women from Denmark to provide information about their exposure and to study indications of common exposure pathways. (
  • 8. The polymer of claim 5 wherein the fluorovinyl ether is copolymerized with a fluoroalkyl vinyl ether having the structure CF 2 ═CFOR 2 f wherein R 2 f is selected from the group consisting of a trifluoromethyl group, a bromodifluoromethyl group, and a heptafluoropropyl group. (
  • 9. The polymer of claim 5 wherein the fluorovinyl ether is copolymerized with a fluoroalkyl vinyl ether, having the structure CF 2 ═CFOR 2 f wherein R 2 f is a C 1 -C 6 perfluoroalkyl group that is a perfluoro-2-propoxypropyl group. (
  • What made you want to look up vinyl ether ? (
  • Diethyl ether is commonly used in chemistry labs as a solvent. (
  • A simple and convenient synthetic protocol for the protection of hydroxyl groups as tetrahydropyranyl ethers as well as carbonyl functionalities as oxathioacetals and thioacetals has been achieved using a catalytic amount of silica-supported perchloric acid under solvent-free conditions. (
  • Tetrahydrofuran ( THF ) is another common ether solvent . (
  • Hydroxypropyl starch ether mainly is a white or colorless powder characterized with a good level of fluidity. (
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  • Until just recently, consumers could only buy Ether (a form of cryptocurrency) with just Bitcoin (another type of crypto). (
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  • 2017. Toxicological profile for Polybrominated Diphenyl Ether. (
  • If the ether is part of a more complex molecule, it is described as an alkoxy substituent, so -OCH 3 would be considered a " methoxy -" group. (
  • In more complicated ethers, the ether group is named as an alkoxy substituent, in which the 'yl' ending of alkyl groups is replaced by 'oxy. (
  • The unusual combination of optical and thermal properties in polyphenyl ethers (PPE) is derived from their molecular structure, as demonstrated by this five-ring PPE molecule. (
  • Molecular recognitionThe size and shape of the cavity formed within a crown ether molecule confers selectivity for complementary ions and small molecules that fit it, like a lock and key. (
  • Because of the flexibility, a crown ether molecule can adjust the size and shape of its cavity to accommodate a range of sizes and shapes of guests, limiting the crown ether's selectivity. (
  • Based on this evidence, exposed to high levels of the chemicals, but cannot tell the the EPA has classified decabromodiphenyl ether as a exact amount or type of PBDE you were exposed to, or possible human carcinogen. (
  • Several classes of emerging contaminants with endocrine disruptive properties were detected in appreciable concentrations, including polybrominated diphenyl ether ( PBDE ) flame retardants, nonylphenols (NPs) detergent breakdown products and the antibacterial agent triclosan . (
  • In the IUPAC nomenclature system, ethers are named using the general formula "alkoxyalkane" , for example CH 3 -CH 2 -O-CH 3 is methoxyethane . (
  • IUPAC rules are often not followed for simple ethers. (
  • Since ethers do not have a hydrogen connected to the oxygen atoms, they are not capable of forming hydrogen bonds to each other. (
  • In addition, the lone pairs on the oxygen atoms in the ether can complex with the magnesium atoms in the Grignard reagent, stabilizing the reagent somewhat. (
  • The first number in the name of a crown ether refers to the number of atoms in the cycle, and the second number refers to the number of those atoms that are oxygen . (
  • Ethers can again be classified into two varieties: if the alkyl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. (
  • Simple ethers are named by naming the alkyl groups in alphabetical order and adding the word 'ether' to the end. (
  • An ether in which the oxygen atom is connected to two methyl groups. (
  • Ethers contain hydrocarbon groups connected by an oxygen atom. (
  • This capability allows chemists to organize a collection of separately weak bonding interactions, such as the electrostatic bond between an ether oxygen atom and a metal ion, to achieve strong, selective binding. (
  • For example, the strength with which a crown ether binds a potassium atom is three times greater in its constrained, rigid state on graphene than in an unconstrained structure. (
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  • 260--465.6 2 Claims ABSTRACT OF THE DISCLOSURE Substituted perfiuorovinyl ethers having the formula CFFCFO(OF ),,-CN where n is from 2 to 12, preferably 2 to 4. (