Alkenyl Ethers Research Articles

Diacyl, alkenyl, and alkyl ether phospholipids in ejaculated, in utero-, and in vitro-incubated porcine spermatozoa.

The phospholipids of porcine spermatozoa were analyzed by a hydrolytic procedure directly after ejaculation, and after incubation for 120 min in vitro or in ligated uterine segments of females with induced estrus. Total phospholipid content of ejaculated sperm was 65.7 micro g lipid P per 10(9) sperm, of which 41% was alkyl ether and 23% was alkenyl ether glycerophospholipid. All of the ether phospholipids were choline and ethanolamine glycerophospholipids. In order of decreasing amount (% of total phospholipid), the phospholipids were choline and ethanolamine glycerophospholipids (49.9 and 28.2), sphingolipid (10.6), cardiolipin (5.5), phosphatidylinositol (2.3), phosphatidic acid (1.5), phosphatidylserine (1.2), and phosphatidylglycerol (0.8). Phosphorus-containing sphingolipid separated into two components during thin-layer chromatography. Sphingosine was the only long-chain base identified in either band. Major fatty acids in the band with lower R(f) were 16:0 (56%), 20:0 (23%), and 18:0 (11%) plus smaller amounts of 14:0, 18:1, and 22:0, while those in the band with higher R(f) were 14:0 (30%), 16:0 (45%), and 18:1 (12%) plus smaller amounts of 18:0, 20:0, and 22:0. Choline was the only water-soluble base present in the lower R(f) sphingomyelin while ethanolamine was prevalent in the higher R(f) component. Incubation of washed spermatozoa in Ca(2+)-free Ringer-fructose at 37 degrees C for 2 hr produced no significant change in the level of any of the phospholipids. Incubation of washed sperm in the uterus for 2 hr, in the presence of oviductal secretions, produced an increase in phosphatidylcholine from 7.2 to 10.2 micro g lipid P per 10(9) sperm.-Evans, R. W., D. E. Weaver, and E. D. Clegg. Diacyl, alkenyl, and alkyl ether phospholipids in ejaculated, in utero-, and in vitro-incubated porcine spermatozoa.

Solvolytic cleavage of alkenylpentafluorosilicates catalyzed by copper(II) acetate. A stereoselective synthesis of ( E)-alkenyl ethers from alkynes

( E)-Alkenylpentafluorosilicates, obtainable from acetylenes via hydrosilylation-silicate formation, react with alcohols in the presence of a catalytic amount of copper(II) acetate under an atmosphere of air (oxygen) at room temperature to form ( E)-alkenyl ethers stereoselectively in satisfactory yields. Similar reaction with water gives aldehydes.

Stereochemistry in cationic polymerization of alkenyl ethers. III. Effect of the alkoxy group on the steric structure of polymers

AbstractPropagation mechanism in the cationic polymerization of alkenyl ethers was investigated through the effect of the bulkiness of alkoxy groups on the steric structure of a polymer. In polymerization with BF3O(C2H5)2 in toluene at −78°C, trans‐propenyl ethers having less bulky alkoxy groups–methyl, ethyl, and benzyl propenyl ethers–produced a stereoregular polymer having a threo‐meso structure, and the cis isomer a nonstereoregular one having threo‐meso and racemic structures. On the other hand, in the polymerization of propenyl ethers having bulky alkoxy groups–isopropyl and 1‐methylpropyl propenyl ethers–the trans isomer yielded a nonstereoregular polymer with threo‐meso and racemic structures, and the cis isomer a stereoregular one with a erythro‐meso structure. This result suggests that a bulky alkoxy group plays an important role in determining the steric structure of the polymer by repulsion between the alkoxy groups of a growing chain end and of a monomer. The effect of solvent polarity on the steric structure of a polymer was also studied.

Turnover rates of the molecular species of alkenyl ether phospholipids of Ehrlich ascites tumor cells.

[1-14C]Glycerol was injected into the peritoneal cavity of mice bearing Ehrlich ascites tumor cells and the lipids were extracted from the cells after selected periods. 1-O-Alkenyl-2-acyl-3-acetylglycerols were prepared from the ethanolamine phosphoglycerides and fractionated by AgNO3-impregnated thin-layer chromatography into five molecular species. Bands 1--5 obtained in this way can be designated as saturated, monoene, diene, tetraene and hexaene species, respectively. Band 5, composed mainly of hexaene species was predominant among those derived from alkenyl ether phospholipids. The specific radioactivities of the fractionated species were determined. Hexaene molecular species turned over most rapidly and disaturated and tetraene species turned over at a high rate, while monoene and diene molecular species turned over very slowly.

Plasmenylethanolamine: growth factor for cholesterol-reducing Eubacterium.

A plasmalogen, plasmenylethanolamine, is required for in vitro growth of strains of Eubacterium which convert cholesterol to coprostanol. Plasmenylethanolamine was isolated from calf brain by selective saponification of lipid fractions separated by thin-layer or column chromatography. Cholesterol-containing thioglycolate broth plus purified plasmenylethanolamine or its 2-lyso derivative supported growth of Eubacterium ATCC 21408 and a cholesterol-reducing Eubacterium isolated from baboon feces. Plasmenylethanolamine obtained from commercial sources also supported growth of these organisms, but none of a number of other pure lipids would support growth. Metabolism of the alkenyl ether group of plasmenylethanolamine occurred during growth.

Stereochemistry in cationic polymerization of alkenyl ethers. II. Formation of poly(ß‐substituted vinyl ether)s with erythro‐meso structures

AbstractThe formation of polymers with erythro‐meso structures, which could not be obtained from propenyl ethers with BF3O(C2H5)2, was studied by 13C‐NMR spectroscopy on poly(ß‐substituted vinyl ether)s obtained under a variety of conditions of polymerization. It was established that poly(cis‐ethyl propenyl ether) obtained with Al2(SO4)3–H2SO4 complex in toluene at 0°C was a highly stereoregular polymer with an erythro‐meso structure. Cis‐2‐chlorovinyl ethyl ether and cis‐methyl and ethyl butenyl ethers also yielded polymers with erythro‐meso structures under the same conditions. In addition, with BF3O(C2H5)2 at −78°C these three cis isomers produced amorphous polymers with threo‐meso, racemic, and, in a few cases, erythro‐meso structures, whereas cis‐ethyl propenyl ether produced polymers with only threo‐meso and racemic structures by the same catalyst. On the other hand, all trans isomers produced stereoregular polymers with threo‐meso structures with BF3O(C2H5)2 at −78°C, regardless of their ß‐substituents; no erythro‐meso structures were found in the polymers obtained.

The effect of the counter-anion on the steric structure of poly(alkenyl ether)s in cationic polymerization

Ethyl propenyl and butenyl ethers were polymerized in toluene at −78°C by a variety of catalysts, and effect of a counter-anion on steric structure of the polymer was investigated. The trans monomer produced stereoregular polymer with threo-meso structure and its content was independent of kind of the catalysts. In the polymerization of the cis monomer, the contents of the threo-meso and racemic structures of the poly(cis-propenyl ether) depended on the kind of the catalysts whereas those of the poly (cis-butenyl ether) having bulky β-ethyl groups did not. The difference of the counter-anion effect was discussed on the basis of the difference of the β-substituent in bulkiness.

Synthesis via silyl alkenyl ethers. 14. Dimethyldicyanosilane: a reagent for concurrent silylation and cyanosilylation of .beta.-diketones

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis via silyl alkenyl ethers. 14. Dimethyldicyanosilane: a reagent for concurrent silylation and cyanosilylation of .beta.-diketonesIlhyong Ryu, Shinji Murai, Akiko Shinonaga, Tetsuro Horiike, and Noboru SonodaCite this: J. Org. Chem. 1978, 43, 4, 780–782Publication Date (Print):February 1, 1978Publication History Published online1 May 2002Published inissue 1 February 1978https://doi.org/10.1021/jo00398a075RIGHTS & PERMISSIONSArticle Views201Altmetric-Citations23LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (305 KB) Get e-Alerts Get e-Alerts

Stereochemistry in cationic polymerization of alkenyl ethers. I. 1H‐ and 13C‐NMR spectra of poly(propenyl ethers)

AbstractBenzyl, ethyl, and deuterated ethyl propenyl ethers (BzPE, EPE, and EPE‐d5, respectively) with different cis/trans isomer ratios were polymerized by BF3O(C2H5)2 at −78°C in toluene, methylene chloride, and nitroethane solvents. Poly(propenyl alcohol) [poly(PA)] was also prepared by treating poly(BzPE) with HBr gas. The steric structure of these polymers was studied by 1H‐ and 13C‐NMR spectroscopy. The poly(EPE‐d5) obtained from a trans‐rich monomer mixture was crystalline, while one from a cis‐rich monomer mixture was amorphous. Poly(BzPE) was always amorphous. Poly(BzPE), poly(PA), and poly(EPE‐d5) gave 1H‐NMR spectra with two β‐methine peaks, relative intensities of which depended on the geometric structure of the monomers. Their spectra of β‐methyl protons decoupled from β‐methine proton were also split into two peaks, relative intensities of which corresponded to those of the two α‐methine peaks. 13C‐NMR spectra of α‐OCH2 and β‐CH3 of poly(EPE), respectively, consisted of two peaks. These observations show that the poly(propenyl ethers) examined, whether crystalline or amorphous, have only two dyad structures (probably threo or erythro‐meso and racemic), and that their α‐ and β‐carbons have the same dyad structure, irrespective of the kind of the alkoxyl groups.

Unusual Simmons-Smith reaction affording noncyclopropyl compounds. New route to 2-methylenecycloalkanols from silyl alkenyl ethers

Bei der Reaktion der Cycloalkenyltrimethylsilylather (I) mit Methylenjodid (II) nach Simmons-Smith erhalt man in Gegenwart von Zn-Cu die Cyclopropane (III), die mit Wasser zu den Carbinolen (IV) verseift werden.

Synthesis via silyl alkenyl ethers. IV. Synthesis of 1-hydroxybicyclo[n.1.0]alkanes from silyl alkenyl ethers. Novel class of cyclopropanols

Synthesis via silyl alkenyl ethers. IV. Synthesis of 1-hydroxybicyclo[n.1.0]alkanes from silyl alkenyl ethers. Novel class of cyclopropanols

Cationic polymerization of α,β‐disubstituted olefins. Part 17. Effect of polymerization conditions on the reactivity of alkenyl ethers relative to vinyl ethers

AbstractIn order to clarify the propagation reaction, vinyl ether was copolymerized with the corresponding alkenyl ether under various conditions. cis‐Propenyl ether (cis‐PE) was several times more reactive than trans‐PE and the corresponding vinyl ether in the copolymerization catalyzed by BF3 · O(C2H5)2 in toluene. However, the reactivity of cis‐PE relative to trans‐PE and the vinyl ether was found to be greatly decreased with increasing polarity of the solvent and to be very close to unity in such polar solvents as nitroethane. On the other hand, the reactivity of trans‐IBPE relative to IBVE was scarcely changed by polymerization conditions. Also, the nature of the initiator and polymerization temperature affect the reactivity of cis‐PE relative to the vinyl ether. These phenomena were explained by the relative stability of the bridged and open car bonium ions based on the polarity of the solvent and steric hindrance due to substituents in the trans isomer.

Gas chromatography in qualitative analysis

Aldehyde dimethyl acetals have been previously shown to undergo decomposition during elution from adsorptive gas-liquid chromatographic columns to yield methyl alkenyl ethers [1, 2]. Evidence has now been obtained through a comparison of the chromatographic behaviour of acetals with their corresponding sulphur analogues, that the mechanism of the decomposition involves initial protonation of an ether oxygen of the acetal, subsequent elimination of one molecule of alcohol to yield a carbonium ion, which may then eliminate a proton to form a vinylic ether.

Silyl alkenyl ethers as the synthetic equivalent of enols. New syntheses of β-keto-sulphides and 1,3-diketones

New syntheses of β-keto-sulphides and 1,3-diketones via the addition of a sulphenyl chloride and polychloroacetyl chlorides to trimethylsilyl alkenyl ethers are described.

Polar lipds in bovin milk: III. Isomeric cis and trans monoenoic and dienoic fatty acids, and alkyl and alkenyl ethers in phosphatidyl choline and phosphatidyl ethanolamin

Phosphatidyl choline and phosphatidyl ethanolamine were prepared from spray-dried buttermilk powder. The compositions of the fatty acids from the 1- and 2-positions of phosphatidyl choline and phosphatidyl ethanolamine were in good agreement with previous analyses. Phytanic acid was present only in the 1-position of phosphatidyl choline (1.0%) and phosphatidyl ethanolamine (0.1%). Trans 17:1 and trans 18:1 acids were principally located in the 1-position of phosphatidyl choline and phosphatidyl ethanolamine while there was a more even distribution of cis 16:1, 17:1, 18:1 and trans 16:1 acids between the two positions of each phosphoglyceride. The distribution of trans monoenes was similar to that of the corresponding saturated acids. There was no selective incorporation of cis positional isomers and little selective incorporation of trans positional isomers into the 1- or 2-position of phosphatidyl choline or phosphatidyl ethanolamine. The principal cis, cis dienoic acid was linoleic acid. Cis, cis dienes were mainly in the 2-position of phosphatidyl choline and phosphatidyl ethanolamine, but cis, trans and trans, trans conjugated dienes were more evenly distributed. The alkyi and alkenyl ethers of phosphatidyl choline contained mostly branched 14:0–19:0, normal 14:0, 16:0, 18:0 and cis 18:1 aliphatic chains. The composition of milk phosphatidyl choline alkenyl ethers is very similar to that of rumen bacteria and protozoan phosphatidyl ethanolamine alkenyl ethers.

Cationic Polymerization of 1, 2-Dialkoxyethylenes

1, 2-Dimethoxyethylene (DME) and 1, 2-diethoxyethylene (DEE) were polymerized by cationic catalysts in order to clarify the effect of an electron-donating group, an alkoxyl group, at an olefinic β-carbon on the reactivity of vinyl ethers in cationic polymerization. Both DME and DEE were found to be very reactive and homopolymers were easily produced at high yield, in spite of the presence of a bulky β-alkoxyl group. A partially crystalline polymer was formed in the polymerization of cis-DME catalyzed by the Al2(SO4)3-H2SO4 complex catalyst. The relative reactivities of 1, 2-dialkoxyethylenes were measured on the basis of the results of copolymerization with vinyl ethers and alkenyl ethers. BF3O(C2H5)2 and toluene were used as catalyst and solvent, respectively. The reactivity of these monomers increases as followsmethyl vinyl ether≤trans-DME<trans-methyl propenyl ether (MPE)<cis-MPE<cis-DMEand ethyl vinyl ether≈trans-DEE<cis-DEE.This order can be explained in terms of a model of the propagation step in which an attacking carbonium ion interacts with the π-electron on the olefinic double bond and the ether oxygen of vinyl ethers.

Structure elucidation of aliphatic aldehydes by mass spectrometry of alkenyl ethers

Structure elucidation of aliphatic aldehydes by mass spectrometry of alkenyl ethers

Nucleophilic substitution at an acetylenic carbon : Competing processes in the reactions of sodium methoxide with phenylbromoacetylene or phenylchloroacetylene in methanol

Phenylhaloacetylenes are triphilic towards methoxide ion in methanol. With phenylchloroacetylene ( 1′), methoxide attacks ∼0·2% on chlorine, ∼99% on carbon 1, and ∼1% on carbon 2; with phenylbromoacetylene ( 1), methoxide attacks ∼5% on bromine, ∼83% on carbon 1, and ∼11% on carbon 2. The first detectable products, phenylacetylene, phenylmethoxyacetylene ( 2), ( E)-β-bromo-β-methoxy- styrene, and ( Z)-β-bromo-α-methoxystyrene lie on discrete mechanistic paths and are not interconvertible under the reaction conditions. Comparable amounts of alkynyl and alkenyl ethers are formed by attack on carbon 1. The element effects for attack on halogen, K(Cl)/k(Br) ⋍ 0·4, and on carbon 1, k(Cl)/L(Br) ⋍ 1·6 are consistent with the notion of independent competing processes. Phenylmethoxyacetylene is a short- lived transient; its formation and decay (with methoxide) rate constants at 78° arc k 1′2 (Cl) 0·6 × 10 −4 * or k 12 (Br) 0·5 × 10 −4 and K j 1·7 × 10 −3 M −1 sec −1. Previously, the intermediacy of alkoxyacetylenes under analogous conditions has only been surmised. In the course of this work, five of the six bromomethoxystyrenes were prepared and some of their distinctive chemistries, as well as those of the corresponding carbonyl compounds, were worked out (eq 2–4).

Interrelationships among the ethanolamine phosphatides in myelinating rat brain.

Abstract— —The ethanolamine phosphatide fraction was isolated from rat brain at 17, 19, and 22 days of age. Analysis by gas‐liquid chromatography of the liberated fatty aldehydes and alkyl glyceryl ethers demonstrated a chain length composition quite distinct from that of the fatty acids in the comparable 1(3)‐position of the diacyl phosphatides. [1‐14C]‐Acetate was administered intraperitoneally to 17‐day‐old rats. With the exception of the polyunsaturated fatty acids, isotope was readily incorporated into the individual side chains of the 1‐ and 2‐positions of the glycerol moiety. Time studies revealed no readily discernible precursor‐product relationships among the linkages in question. Therefore, although the long chain precursors for the alkenyl and alkyl ethers may be related by biosynthetic interconversion, the isotope data are suggestive of independent pathways of biosynthesis for the alkenyl ether, alkyl ether, and ester linkages.

13C NMR spectra and reactivity in cationic polymerization of vinyl and alkenyl ethers

¹³C NMR spectra and reactivity in cationic polymerization of vinyl and alkenyl ethers