Showing papers on "Ether published in 1975"

Process for manufacturing olefins

Abstract: A lower alcohol and/or ether feed is selectively converted to a mixture of light olefins, including ethylene and propylene, by catalytic contact of the feed, for example methanol or dimethyl ether, at subatmospheric partial pressure, with certain crystalline aluminosilicate zeolite catalysts exemplified by HZSM-5.

Synthesis of Guaiacylglycerol-β-guaiacyl Ether

Abstract: Guaiacylglycerol-ß-guaiacyl ether (i), the model compound of arylglycerol-ß-aryl ether structure in lignin was synthesized in high yield through five reaction steps from vanillin. The key step of this synthetic method was the condensation reaction between ethyl 2-methoxyphenoxy acetate (4) and benzyl vanillin (5). At this step, lithium diisopropyl amide was used as the basea and /?-hydroxy ester (6) was obtained in 95 % yield as an oily substance consisted of two isomers, from which only erythro isomer was obtained as crystal in 51 % yield. The residual oily substance was converted to its carbamate (7) and crystallized in 70% yield. The crystalline /Miydroxy ester (6) and the carbamate (7) were then converted to the final compound (i) by the lithium aluminum hydride reduction and subsequent hydrogenation with Pd-C. The overall yield of the guaiacylglycerol-/?guaiacyl ether (i) from benzyl vanillin (5) was about 72%.

Relation between van der Waals and Partial Molal Volumes of Organic Molecules in Water

Abstract: The partial molal volumes of nonpolar organic molecules (i.e. those having more than three aliphatic carbon atoms per polar hydroxyl, ether, amine, amide, or urea group) in water at 25 °C are given...

Modification of stress-induced prolactin release by dexamethasone or adrenalectomy.

Abstract: A study was conducted to determine the influence of conditions known to alter ACTH secretion on prolactin release by the pituitary. Dexamethasone or 0.9% NaCl was injected subcutaneously into intact male rats 4 hr before a 2-min ether stress. Other rats were submitted to the ether stress 2 weeks following adrenalectomy. Five min following exposure to the ether stress, the rats were decapitated and trunk blood was collected. Plasma levels of prolactin were determined by radioimmunoassay. Dexamethasone (31, 125 or 500 µg/kg) blocked the stress-induced prolactin release in a dosage dependent manner with the highest dose decreasing plasma prolactin to levels similar to those observed in rats not exposed to the ether stress. Conversely, adrenalectomy was found to potentiate prolactin release due to ether stress. The results indicate that the adrenal may play a regulatory role in stress-induced prolactin release. They are also consistent with the suggestion that a common pathway or mechanism may be involved in ...

Polyesters of derivatives of hydroquinone and bis(carboxyphenyl)ether

Abstract: This invention relates to a class of novel polyesters derived from derivatives of hydroquinone and bis(carboxyphenyl)ether and to the fibers and other shaped articles prepared therefrom. Also comprehended by this invention are the novel, optically anisotropic polyester melts from which these shaped articles can be prepared.

4-Trifluoromethylimidazoles and 5-(4-pyridyl)-1,2,4-triazoles, new classes of xanthine oxidase inhibitors.

Abstract: The syntheses of a number of 2-substituted 4-trifluoromethylimidazoles and 3-substituted 5-(4-pyridyl)-1,2,4-triazoles are described. The trifluoromethylimidazoles were prepared from 3,3-dibromo-1,1,1-trifluoroacetone after hydrolysis with aqueous sodium acetate solution and condensation with an aldehyde in the presence of ammonia. Basic hydrolysis of the trifluoromethyl group was found to provide a facile method for the synthesis of imidazole-4-carboxylic acids. In the imidazole series a 2-aryl substituent and a free imino group were required for xanthine oxidase inhibitory activity. The triazoles were obtained through the reaction of an aroylhydrazine and an imino ether followed by thermal ring closure of the intermediate acylamidrazone. As in the imidazole series, a free imino group is an absolute requirement for in vitro activity. Additional structure-activity relationships of these compounds are presented.

Polymers comprising vinyl esters-crotonic acid

Abstract: Copolymers of vinyl acetate, crotonic acid and an unsaturated ester or ether are employed in cosmetic compositions for the hair.

Novel starch ethers

Abstract: A reagent useful for the chemical modification of starch is prepared by the reaction of a 2,3-dihalopropionic acid or alkyl ester thereof with a secondry amine. The reaction of the reagent with starch, carried out in an aqueous solution under controlled conditions, produces novel amino acid ether derivatives which are characterized by the presence of both a cationic and an anionic substituent group on the same reactive site. The resulting starch ethers are characterized by their stability, their ability to form cooked pastes which are more resistant to gelling upon cooling and their lowered gelatinization temperatues.

Racemization of Amino Acid Residues Fused in Thiazoline, Oxazoline, and Imidazoline Rings

Abstract: For the purpose of study on racemization of exo methine carbon atom of thiazoline, oxazoline or imidazoline ring, the following four compounds were synthesized from amino acid imino ether: 2-(1-benzyloxycarbonylaminoethyl)-2-thiazoline (I), methyl 2-(1-benzyloxycarbonylaminoethyl)-2-thiazoline-4-carboxylate (II), methyl 2-(1-benzyloxycarbonylaminoethyl)-2-oxazoline-4-carboxylate (III), and 2-(1-benzyloxycarbonylaminoethyl)-2-imidazoline (IV). A racemization rate of the alanine residue was measured from an optical rotation of 2,4-dinitrophenyl derivative obtained from the acid hydrolyzate and from hydrogen-deuterium exchange reaction at α-carbon atom. All these compounds were found to be racemized very easily particularly in the presence of proton source. From the experimental results, a plausible mechanism for racemization peculiar to such heterocyclic compounds through protonation-deprotonation process was presented.

Pharmaceutical capsules from improved thermogelling methyl cellulose ethers

Abstract: Improved thermogelling methyl cellulose ether compositions for use in preparing pharmaceutical capsules by the pin dip coating process are prepared by blending the properties of water soluble methyl and C 2 -C 3 hydroxyalkyl cellulose ethers to achieve an essentially Newtonian dip coating solution and a rapid high thermal gel yield strength These properties require a cellulose ether with a relatively narrow molecular weight distribution Blends of low viscosity methyl cellulose and hydroxypropylmethyl cellulose provide particularly suitable dip solution properties, gel yield strength, and capsule dissolution rates

Sized carbon fibers

Abstract: Carbon fibers are coated with a sizing composition comprising a polyglycidyl ether, cycloaliphatic polyepoxide or their mixtures. Preferred sizes are mixtures of a liquid diglycidyl ether or bisphenol A and a solid diglycidyl ether of bisphenol A.

Method for preparing low-substituted cellulose ethers

Abstract: In the process for the preparation of low-substituted cellulose ethers comprising the successive steps of etherification of alkali cellulose, neutralization of the crude cellulose ether, washing, drying and pulverization, the neutralization step is carried out in two stages, i.e., by first employing 5 to 80% of an acid stoichiometrically required and then adding an additional amount of the acid to complete neutralization. The cellulose ethers thus prepared can readily be pulverized into fine powder having a very good flowing property and yet an excellent binding force, and work as a suitable disintegrator in tablets.

Synthesis of thebaine and oripavine from codeine and morphine

Abstract: A practical synthesis of thebaine and oripavine has been developed from codeine and morphine, respectively. Attempts to use a codeinone intermediate gave poor yields; however, methylation of the potassium salt of codeine to give codeine methyl ether followed by oxidation with gamma-MnO2 gave thebaine in 67% yield from codeine. Similarly, the potassium salt of the di-O-anion of morphine was selectively alkylated to give morphine 6-methyl ether (heterocodeine) in better than 90% yield. Hetercodeine was then acetylated and oxidized to oripavine 3-acetate which was hydrolyzed to give oripavine in 73% yield from morphine.

Method for inhibiting the polymerization of acrylic acid or its esters

Abstract: A method for inhibiting the polymerization of acrylic acid or acrylic esters during the distillation for separating or purifying the acrylic acid obtained by the vapor phase catalytic oxidation of propylene or acrolein, or the acrylic esters derived from said acrylic acid, said method comprising carrying out the distillation operation in the presence of (A) at least one compound selected from the group consisting of hydroquinone, hydroquinonemonomethyl ether, cresols, phenols, t-butyl catechol, diphenylamine, phenothiazines and methylene blue (B) at least one compound selected from the group consisting of copper dimethyldithiocarbamate, copper diethyldithiocarbamate copper dibutyldithiocarbamate and copper salicylate: and (C) molecular oxygen.

Über enolisierte Derivate der Chlorophyllreihe. 132‐Desmethoxycarbonyl‐173‐desoxy‐132,173‐cyclochlorophyllid a‐enol und eine Methode zur Einführung von Magnesium in porphinoide Ligandsysteme unter milden Bedingungen. (Vorläufige Mitteilung)

Abstract: Magnesium transfer from the iodo-magnesium salt of 3,5-di-t-butyl-4-hydroxy-toluene (BHT) into methyl pheophorbide a is a fast process in methylenechloride/ether solution at ambient temperature. This procedure for the introduction of magnesium into labile chlorin ligands has made possible the preparation of a crystalline 132, 173-cyclochlorophyllide a-enol. Concomitant use of the lithium salt of BHT facilitates the more critical insertion of magnesium into methyl bacteriopheophorbide a. The preparative success of these magnesium transfers depends crucially upon the solvent system used. Under conditions where the complexation of methyl pheophorbide a with iodo-magnesium-BHT is essentially complete within 2 minutes at 12° in methylenechloride/ether solution, strong inhibition of the magnesium transfer is observed by cosolvents such as pyridine, dimethylacetamide, dioxan or tetrahydrofuran.

Preparation of carboxylic acid anhydrides

Abstract: A carboxylic acid anhydride, such as acetic anhydride, is prepared from a carboxylate ester or a hydrocarbyl ether in carbonylation processes comprising the use of an iodide, carbon monoxide and a nickel-chromium catalyst in the presence of a promoter comprising an organo-nitrogen compound or an organo-phosphorus compound wherein the nitrogen and phosphorus are trivalent.

Method for preparation of ethers

Abstract: Novel gasoline compositions, which are characterized by improved octane number and volatility properties, contain both methyl t-butyl ether and methyl t-amyl ether.

The formation of tritiated O-alkyl lipid from acyldihydroxyacetone phosphate in the presence of tritiated water.

Abstract: Previous studies from this laboratory on the mechanism of O-alkyl bond formation using a microsomal system from Tetrahymena pyriformis have shown that O-alkyl lipid synthesized from dihydroxyacetone phosphate has exchanged one hydrogen stereospecifically from the 1-sn position of the glycerol moiety. Indirect evidence suggested that acyldihydroxyacetone phosphate, an intermediate in )-alkyl lipid synthesis, is probably not the locus of the exchange. In the present study in was shown that stable acyldihydroxyacetone phosphate incubated in the presence of tritiated water and Tetrahymena microsomes does not become tritiated. When hexadecanol is added to the system O-alkyl lipid is produced which has incorporated one atom of hydrogen for each mole of hexadecanol at all time periods examined. Experiments in Ehrlich ascites tumor cells have shown that the hydrogen exchange also occurs in a mammalian system. The results indicate that the mechanism of O-alkyl lipid ether bond formation involves a hydrogen exchange and that this exchange occurs after the formation of acyldihydroxyacetone phosphate.

Flexible thermosetting acrylic enamels

Abstract: A thermosetting acrylic enamel, useful for coating automobile and truck bumpers, flexible filler panels located between the bumper and the chassis, flexible fender extensions, and other energy absorbing parts, contains the following film-forming constituents: (A) an acrylic polymer of an alkyl acrylate having 2-8 carbon atoms in the alkyl group, and α,β-ethylenically unsaturated carboxylic acid, an alkyl methacrylate having 1-18 carbon atoms in the alkyl group or mixtures of such an alkyl methacrylate and styrene, and a hydroxyalkyl acrylate or methacrylate having 2-4 carbon atoms in the alkyl group or mixtures thereof; (B) a polyester having a molecular weight not above 2,000, a hydroxyl number range of 50-150, and a glass transition temperature below 25°0 C; prepared from linear or branched chain diols, including ether glycols, or mixtures thereof or mixtures of diols and triols, containing up to and including 8 carbon atoms and a dicarboxylic acid, an anhydride thereof or mixtures of dicarboxylic acids, containing up to and including 12 carbon atoms, wherein at least 75% by weight, based on the weight of dicarboxylic acid, is an aliphatic dicarboxylic acid; and (C) a nitrogen resin corsslinking agent.

Electron Mobilities and Ranges in Liquid Ethers: Ion-like and Conduction Band Mobilities

Abstract: The free ion yields in X irradiated ethers are larger than those in alkanes because the dielectric constants of the former liquids are greater than those of the latter. The relative increase of the free ion yield with temperature is smaller in ethers than in alkanes because the dielectric constants decrease more rapidly with increasing temperature in the former. The density normalized penetration range (thermalization length) bGPd of the secondary electrons in dimethyl ether (DME) is 3.5 × 10−7 g/cm2. As the length of the n-alkyl groups on the ether is increased bGPd increases towards the value obtained for long chain n-alkanes, 4.5 × 10−7 g/cm2. Electron mobilities ue showed two types of behavior: (i) at low temperatures ue approaches a value of about 2u−, where u− is the mobility of the anions formed in the irradiated liquid; (ii) at higher temperatures the ratio ue/u− increases with temperature, and equals 21 in di-n-butyl ether (DBE) at 375 K. The activation energy of electron migration at low tempera...

Containing hindered phenolic norbornane-2,3-dicarboximides stabilized compositions

Abstract: Compounds having the formula ##SPC1## Wherein R 1 and R 2 are lower alkyl, X and Y are hydrogen or, when taken together, they form a bond or an ether linkage, m is 0 to 3, and n is 0 to 2, are good ultraviolet light stabilizers for synthetic polymers.