Showing papers on "Ether published in 1981"

Antifungal Activity of Components of Essential Oils

Abstract: Antifungal activities were examined and compared for some 40 kinds of aliphatic and aromatic aldehydes, alcohols, phenolic compounds, ether compounds and hydrocarbons from essential oils and for some related compounds, using seven fungi.

Penetrating topical pharmaceutical compositions

Abstract: A large group of lipophilic, pharmacologically active compounds can be effectively delivered across intact skin by applying them topically in a binary, penetration-enhancing vehicle containing (1) a C3 -C4 diol, diol ester, or diol ether and (2) a cell envelope-disordering compound. This vehicle provides surprising enhancement of skin penetration for the pharmacological active, compared to either component alone.

Evidence for involvement of penicillin-binding protein 3 in murein synthesis during septation but not during cell elongation.

Abstract: Furazlocillin (1 microgram/ml) and piperacillin (5 microgram/ml) bound specifically to penicillin-binding protein 3 (PBP-3) and not to the other major PBPs in intact Escherichia coli cells. The effect of this specific binding to PBP-3 on murein synthesis of elongating and synchronously septating cells was investigated in two thermosensitive division mutants, E. coli BUG6 and E. coli JE10730, the latter possessing a thermolabile PBP-3. Synchronous cell division was induced by shifting the cultures from the nonpermissive temperature (42 degrees C) to 30 degrees C. Both [14C]diaminopimelic acid incorporation into murein of intact cells and [14C]N-acetylglucosamine incorporation into murein of cells permeabilized with ether was inhibited by an average of 42% in septating cells. In filaments growing at the nonpermissive temperature, we detected no inhibition and, frequently, a 10 to 15% stimulation of murein synthesis. The two drugs, at concentrations used in the above experiments, bound exclusively to PBP-3 both in elongating and septating intact cells and in ether-treated cells. These results support the hypothesis that PBP-3 activity is exclusively required for septal murein synthesis.

Rapid Preparation of Fatty Acid Methyl Esters Using Organic Base-Catalyzed Transesterification

Abstract: Tetramethylammonium hydroxide in methanol (TMAH) is used to catalyze the transesterification of the fat dissolved in diethyl ether; methyl esters form almost instantly. Glycerin drops out of solution to form a second layer containing the bulk of any free fatty acids present as the TMAH soaps. Gas chromatography of the ether layer gives the fatty acid composition of the glycerides. On injecting the lower layer, the TMAH soaps pyrolyze to form methyl esters. If methanol is added to the flask to solubilize the glycerin and excess base neutralized with methanolic hydrochloric acid, total fatty acid composition can be obtained by chromatographing the resulting solution. -- AATA

A mild procedure for the regiospecific benzylation and allylation of polyhydroxy-compounds via their stannylene derivatives in non-polar solvents

Abstract: The reactions of benzyl and allyl bromides on the stannylene derivatives of polyhydroxy-compounds, which normally proceed only at insignificant speed in refluxing benzene solution, are greatly accelerated in the presence of quaternary ammonium halides. These conditions were tested on benzyl β-D-galactopyranoside (1) and ten derivatives, (2)–(11), which were benzylated, allylated, or acetalated. In such a collection may be found all the possible arrangements, except one, of two, three, or four hydroxy-groups on a β-D-galactopyranoside ring. Regiospecific substitution in good yield was observed on nine of the starting polyols. Benzylation in this way of benzyl 2,3-di-O-benzyl-α-D-glucopyranoside only gave the 6-O-benzyl ether in 80% yield, a great improvement over the reaction in NN-dimethylformamide, which has no preparative value. The same new method allows a smooth preparation of the monomethoxymethyl ethers of glycols. The preparations and synthetic uses of the stannylene derivatives of γ-and Iµ-glycols are reported for the first time.

Low Temperature Air Oxidation of Caking Coals: Fourier Transform Infrared Studies

Abstract: Fourier transform infrared spectroscopy has been used to characterize the oxidation of a coking coal. The results demonstrate that the most important initial products of oxidation are carbonyl and carboxylic acid groups. Bands associated with carbon-oxygen single bonds, as in ethers or phenols, do not become prominent until the later stages of the oxidative process. Upon reaction with potassium in tetrahydrofuran a number of changes in the spectrum of both the oxidized and unoxidized coal become apparent. This reagent cannot be considered specific for cleavage of ether bonds, but can also lead to products usually associated with air oxidation.

Extraction of alkali metal cations from aqueous solutions by a crown ether carboxylic acid

Abstract: Solvent extraction of alkali metal cations from aqueous solutions by sym-dibenzo-16-crown-5-oxyacetic acid in chloroform is reported. Influence of pH, metal ion identity and concentration in the aqueous phase, and anion identity in the aqueous phase upon the concentrations of metal and complexing agent in the organic phase are assessed for single ion extractions. Extraction efficiency is insensitive to changing the aqueous phase anion from chloride to sulfate which demonstrates that the anion is not transferred to the organic phase during extraction. Extraction efficiency is very sensitive to the pH of the aqueous phase. For competitive ion extractions, the selectivity is K > Na > Rb greater than or equal to Cs > Li for pH 6 to 7 and Na > K > Rb approx. = Cs > Li for pH 8 to 12. The crown ether carboxylic acid exhibits extraction efficiencies and selectivities which surpass those of sym-dibenzo-16-crown-5 methyl ether or phenoxyacetic acid.

Thermoplastic resin composition

Abstract: PURPOSE:To prepare the titled compositon having excellent impact strength and high-temperature moldability,by compounding a block copolymer of a conjugated diene and a vinyl aromatic hydrocarbon with a specific amine stabilizer or a mixture of said stabilizer and a radical polymerization inhibitor. CONSTITUTION:The objective composition is prepared by compounding (A) a thermoplastic resin with (B) a block copolymer of a conjugated diene and a vinyl aromatic hydrocarbon and (C) an amine stabilizer having at least one nitrogen atom and one sulfur atom in the molecule or a mixture of said stabilizer and a radical polymerization inhibitor. The amount of the component (C) is 0.001-10pts.wt. per 100pts. of the component (B). The weight ratio of the amine stabilizer to the radical polymerization inhibitor is 99/1-10/90, and the radical polymerization inhibitor is pref. hydroquinone, hydroquinone monoalkyl ether, etc. A high-density polyethylene resin, a fluororesin, etc. can also be used effectively as the component (A).

Method for treating polypropylene ether and poly-1,2- butylene ether polyols

Abstract: Polyetherpolyols containing residues of catalysts of the double metal cyanide complex class are treated with a strong base and ion exchanged or neutralized and filtered to provide a stable polyol with reduced tendency to form allophanates with diisocyanates. Further, the addition of ethylene oxide to the polyol while in contact with the strong base serves to end cap the polyol to provide it with primary hydroxyl groups.

β -Ether cleavage of the lignin model compound 4-ethoxy-3-methoxyphenylglycerol- β -guaiacyl ether and derivatives by Phanerochaete chrysosporium

Abstract: The white rot basidiomycete Phanerochaete chrysosporium metabolized 4-ethoxy-3-methoxyphenyl-glycerol-β-guaiacyl ether (V) in low nitrogen, stationary cultures under which conditions the ligninolytic enzyme system is expressed. 4-Ethoxy-3-methoxyphenylglycerol XIII, guaicol and 4-ethoxy-3-methoxybenzyl alcohol (II) were isolated as metabolic products. Exogenously added XIII was rapidly converted to 4-ethoxy-3-methoxybenzyl alcohol indicating that it is an intermediate in the metabolism of V. P. chrysosporium also metabolized 1-(4′-ethoxy-3′-methoxyphenyl)-2-(2″-methoxyphenoxy)-3-hydroxypropane VI. The degradation pathway for this dimer also included initial β-ether cleavage and α-hydroxylation of the diol product 1-(4′-ethoxy-3′-methoxyphenyl) 2,3 dihydroxypropane (XI) to yield the triol XIII which was cleaved at the α, β bond to yield 4-ethoxy-3-methoxybenzyl alcohol. Finally P. chrysosporium also cleaved the dimer 1-(4′-ethoxy-3′-methoxyphenyl)-2-(2″-methoxyphenoxy)-1-hydroxypropane (VIII) at the β-ether linkage yielding 1-(4′-ethoxy-3′-methoxyphenyl) 1,2 dihydroxypropane (IX) which was subsequently cleaved at the α, β bond to yield II. All of the results indicate that oxidative β-ether cleavage is an important initial reaction in the metabolism of β-aryl ether lignin substructure dimeric compounds. Metabolities were identified after comparison with chemically synthesized standards by gas liquid chromatography-mass spectrometry.

Modification of sodium and potassium channel gating kinetics by ether and halothane.

Abstract: The effect of ether and halothane on the kinetics of sodium and potassium currents were investigated in the crayfish giant axon. Both general anesthetics produced a reversible, dose-dependent speeding up of sodium current inactivation at all membrane potentials, with no change in the phase of the currents. Double-pulse inactivation experiments with ether also showed faster inactivation, but the rate of recovery from inactivation at negative potentials was not affected. Ether shifted the midpoint of the steady-state fast inactivation curve in the hyperpolarizing direction and made the curve steeper. The activation of potassium currents was faster with ether present, with no change in the voltage dependence of steady-state potassium currents. Ether and halothane are known to perturb the structure of lipid bilayer membranes; the alterations in sodium and potassium channel gating kinetics are consistent with the hypothesis that the rates of the gating processes of the channels can be affected by the state of the lipids surrounding the channels, but a direct effect of ether and halothane on the protein part of the channels cannot be ruled out. Ether did not affect the capacitance of the axon membrane.

Preparation of Cationic Starch Ether: A Reaction Efficiency Study *

Abstract: Cationic starch ether, important as a papermaking additive, was prepared from native corn starch and 2-chloro-3-hydroxypropyltrimethylammonium chloride in aqueous media in a study to ascertain conditions yielding maximum reaction efficiency (RE). Based on the amount of monomer retained after exhaustive washing procedures, RE values of 84–88% were achieved with 0.025–0.05 mole of monomer/mole of starch. Degrees of substitution of up to 0.075 were investigated. A number of variables were studied that allow high RE under a variety of reaction conditions, including those involving low energy input. The excellent stability of the monomer during etherification suggests that the water-soluble active monomer and salts could be recycled in subsequent reactions.

Dimethylisopropylsilyl ether derivatives in gas chromatography mass spectrometry of prostaglandins and thromboxane B2

Abstract: The dimethylisopropylsilyl ether derivatives of PGF1α and PGF2αmethyl esters and PGD2, PGE1, PGE2, 6-Keto PGF1α and thromboxane B2 methoxime-methyl esters were separated completely within 15 min by gas chromatography using open tubular glass capillary column coated with SE-30. The methylene unit values of these derivatives were slightly greater than those of the corresponding dimethyl-n-propylsilyl ether derivatives. The use of the dimethylisopropylsilyl ether derivatives made it possible to perform the baseline separation of PGs and thromboxane B2 which were not separated by the trimethylsilyl ether derivatives. The mass spectral fragmentation of these dimethylisopropylsilyl ether derivatives was similar to those of the corresponding trimethysilyl ether derivatives, reported in a previous paper. Their mass spectra were characterized by the molecular ion, [M]+., and the ions [M—15]+ and [M—43]+ like those in the hydroxysteroid dimethylisopropylsilyl ether derivatives reported previously. The ion [M—34]+, which is produced by the elimination of isopropyl group from [M]+., was observed as an intense peak. The appearance of this ion in the high mass region was very useful for quantitation of trace amounts of PGs and thromboxane B2 in biological fluids without disturbance of endogenous substances by selected ion monitoring. The detection limit of the dimethylisopropylsilyl ether derivative of PGF2α methyl ester was found to be 5 pg with a signal-to-noise ratio of 10:1 when monitoring the ion [M—43]+ (m/z 625).

Complexes of Lanthanoid Nitrates with 15-Crown-5 and 18-Crown-6 Ethers†‡

Abstract: Complexes between the heavier lanthanoid nitrates Ln(NO3)3 and 15-crown-5 (1) and 18-crown-6 (2) ethers were isolated and characterized. Both 1:1 and 4:3 complexes are formed with each Ln(III) ion, except in the case of Gd and 2. The thermal transformation of the 1:1 complexes into the corresponding 4:3 complexes was studied by thermogravimetry and by DSC, X-ray and vibrational data provide information about the structure of these complexes. The interaction between Ln(III) ions and ligands 1 and 2 in non-aqueous solutions is discussed on the basis of conductometric, fluorescence, UV./VIS. and 1H-NMR. data. Only 1:1 complexes of 2 formed in solution and their formation constants range from logKf = 4.4 (Ln = La) to 2.4 (Ln = Yb); for Eu, Kf of the 15-crown-5 and 18-crown-6 ether complexes are of the same order of magnitude. For La, Pr, Nd, Eu, Yb, a variable temperature NMR. study gave some indications about the chemical exchanges in solution. The factors which determine the stoichiometry of the complexes are discussed.

Gradient interpenetrating polymer networks. I. Poly(ether urethane) and polyacrylamide IPN

Abstract: The swelling properties of poly(ether urethane)s and the preparation of interpenetrating polymer networks (IPNs) from a poly(ether urethane) thermoplastic elastomer and hydrogel forming polyacrylamide have been studied. The acrylamide monomer was polymerized with simultaneous crosslink formation, in the presence of the swollen thermoplastic elastomer. Upon removal of the swelling solvent, an IPN was obtained which absorbed water in the manner of a hydrogel but had mechanical properties superior to a hydrogel.

Ether imides and process for producing the same

Abstract: An ether imide of the formula: ##STR1## wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and D are as defined in the specification produced by reacting a diamine with an ethylenically unsaturated dicarboxylic acid can give a composition together with one or more unsaturated polyesters, epoxy compounds, amines, and the like to give shaped articles excellent in flexibility and heat resistance.