- Design, synthesis, and properties of neoglycolipids based on ethylene glycoles conjugated with lactose as components of targeted delivery systems of biologically active compounds
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Synthesis has been developed of a series of new aliphatic lactose derivatives as components of liposomal targeted delivery systems distinguished by the length and the number of aliphatic chains and also by the length of the spacer fragment. The structure of compounds synthesized has been established by means of 1H NMR spectroscopy. Pleiades Publishing, Ltd., 2012.
- Gur'eva,Bol'sheborodova,Sebyakin
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- Novel titanium(IV) diolate complexes with additional O-donor as precatalyst for the synthesis of ultrahigh molecular weight polyethylene with reduced entanglement density: Influence of polymerization conditions and its implications on mechanical properties
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New alkoxo-titanium(IV) complexes with diolate ligand containing additional donor oxygen atom have been synthesized from readily available and scalable precursors. The structure of complex 4 was established by X-ray diffraction. Titanium atom adopts a distorted tetrahedral geometry formed by six oxygen atoms of ligands. The resulting complexes 3–4 are moderately or highly active in ethylene polymerization in the presence of {EtnAlCl3–n + Bu2Mg} binary cocatalysts. The influence of the nature of the solvent, the organoaluminum cocatalyst and the polymerization temperature on the activity of catalytic systems, and the properties of the resulting polymers were studied. The obtained polymers are linear polyethylene of ultrahigh molecular weight (up to 5.8·106 g mol?1) with a broad molecular weight distribution. The polymers are suitable for the modern methods of polymer processing—the solventless solid-state formation of super high-strength (breaking strength up to 2.8 GPa) and high-modulus (elastic modulus up to 140 GPa) oriented films and film tapes. The possibility of scaling up the synthesis of ultrahigh molecular weight polyethylene (UHMWPE) without a significant drop in the productivity of the catalytic system and polymer properties is shown. UHMWPE samples have been investigated by small-angle X-ray scattering (SAXS) methods to study the structural changes induced by solid-state drawing of nascent reactor powders.
- Tuskaev, Vladislav A.,Gagieva, Svetlana Ch.,Kurmaev, Dmitrii A.,Bogdanov, Vyacheslav S.,Magomedov, Kasim F.,Mikhaylik, Elena S.,Golubev, Evgenii K.,Buzin, Mikhail I.,Nikiforova, Galina G.,Vasil'ev, Viktor G.,Khrustalev, Viktor N.,Dorovatovskii, Pavel V.,Bakirov, Artem V.,Shcherbina, Maksim А.,Dzhevakov, Pavel B.,Bulychev, Boris M.
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- Synthesis of Dicarboxylic Acids from Aqueous Solutions of Diols with Hydrogen Evolution Catalyzed by an Iridium Complex
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A catalytic system for the synthesis of dicarboxylic acids from aqueous solutions of diols accompanied by the evolution of hydrogen was developed. An iridium complex bearing a functional bipyridonate ligand with N,N-dimethylamino substituents exhibited a high catalytic performance for this type of dehydrogenative reaction. For example, adipic acid was synthesized from an aqueous solution of 1,6-hexanediol in 97 % yield accompanied by the evolution of four equivalents of hydrogen by the present catalytic system. It should be noted that the simultaneous production of industrially important dicarboxylic acids and hydrogen, which is useful as an energy carrier, was achieved. In addition, the selective dehydrogenative oxidation of vicinal diols to give α-hydroxycarboxylic acids was also accomplished.
- Fujita, Ken-ichi,Toyooka, Genki
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- Domino Two-Step Oxidation of β-Alkoxy Alcohols to Hemiacetal Esters: Linking a Stoichiometric Step to an Organocatalytic Step with a Common Organic Oxidant
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Primary and secondary β-alkoxy alcohols can be cleanly and efficiently oxidized into hemiacetal esters in a cascade two-step process. mCPBA serves both as a stoichiometric oxidant in the first TEMPO-catalyzed step, converting alcohols to aldehydes/ketones, and as a reagent in the second Baeyer–Villiger stoichiometric oxidation, transforming the aldehydes/ketones into hemiacetal esters. The use of an oxidant common to both steps enables the domino reaction to proceed under a single experimental setting. Longer oxidative cascade sequences are possible when this new methodology is applied to suitable substrates.
- Targel, Tom,Ramesh, Palakuri,Portnoy, Moshe
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supporting information
p. 3017 - 3021
(2018/06/27)
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- Reactions of peroxide products of ozonolysis of allyl ethers/esters in the AcOH-CH2Cl2 system on treatment with semicarbazide hydrochloride
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Background: A one-pot method for the preparation of the corresponding alkoxy acetic acids by low-temperature ozonolysis of allyl ethers/esters followed by treatment with semicarbazide hydrochloride has been suggested. The reaction occurs via formation of acetoxyhydroperoxide, subsequent reduction of which depends on the process temperature and the nature of the starting substrate. Objective: The article is aimed at the development of one-pot method for obtaining practically important alkoxy acetic acids, because the ozonolytic cleavage of a ?=? double bond is the key step in full syntheses of many biologically active compounds. Methods: We used a low temperature ozonolysis of functionally substituted olefins in the system acetic acid-methylene dichloride followed by reduction of semicarbazide hydrochloride. To create a method we have used available allyl ethers/esters as starting materials. Results: We investigated reaction of the peroxide products of ozonolysis of monoallyl ethers, ester and diallyl ethers in an AcOH/CH2Cl2 mixture on treatment with semicarbazide hydrochloride at various temperatures. We have discovered that the selectivity of reduction of acetoxyhydroperoxide formed at the first stage depends both on the process temperature and on the nature of the starting substrate. A decrease in temperature favors acid hydrolysis and formation of a carboxylic acid. Conclusion: We have proposed a simple and highly efficient one-pot method for the preparation alkoxy acetic acids without isolation of intermediate peroxides.
- Raskil'dina, Gulnara Z.,Legostaeva, Yuliya V.,Garifullina, Liliya R.,Sultanova, Rimma M.,Ishmuratov, Gumer Y.,Zlotskii, Simon S.
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p. 652 - 656
(2017/01/13)
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- Oxidative Cleavage of Vicinal Diols with the Combination of Platinum and Vanadium Catalysts and Molecular Oxygen
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The combination of Pt/C and V2O5 catalysts gave good performance for the oxidative cleavage of trans-1,2-cyclohexanediol into adipic acid via 2-hydroxycyclohexanone. The yield of adipic acid reached 90 % in the one-pot oxidative cleavage of trans-1,2-cyclohexanediol. The yield was higher than that obtained in the oxidation of 2-hydroxycyclohexanone with V catalyst, and the higher yield was due to the low 2-hydroxycyclohexanone concentration during the one-pot oxidation of trans-1,2-cyclohexanediol. Cyclic vicinal diols having a six-membered ring and linear vicinal diols having two secondary OH groups were converted into dicarboxylic acids and two carboxylic acids, respectively. The activity of the Pt catalyst decreased during the reaction, and the activity was partially restored by treating the used catalyst with H2 at 573K. Even without regeneration, the turnover number based on total Pt could reach ≈1000 in a long reaction with an increased amount of trans-1,2-cyclohexanediol.
- Obara, Naoyuki,Hirasawa, Shota,Tamura, Masazumi,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 1732 - 1738
(2016/05/19)
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- Synthesis of bis-tetrahydroisoquinolines based on homoveratrylamine and a series of dibasic acids. 3.
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Pyrido- and [1, 4]-oxazinoisoquinolines, bis-tetrahydroisoquinolines, the alkaloid corydaldine, cleavage products, and a series of intermediates were prepared from homoveratrylamine and dibasic acids (glutaric and diglycolic) using a Bischler-Napieralski reaction. Their structures were confirmed using IR and NMR spectra and an x-ray crystal structure analysis.
- Sh.saidov,Mazur,Turgunov,Tashkhodzhaev,Levkovich,Vinogradova
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p. 503 - 510
(2014/08/18)
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- HYDROCARBOXYLATION OF METHYLENE DIPROPIONATE IN THE PRESENCE OF PROPIONIC ACID AND A HETEROGENEOUS CATALYST
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Disclosed is a process for the production and purification of glycolic acid or glycolic acid derivatives by the carbonylation of methylene dipropionate in the presence of a solid acid catalyst and propionic acid. This invention discloses hydrocarboxylations and corresponding glycolic acid separations wherein the propionic acid stream is readily removed from the glycolic acid and the propionic acid is recycled.
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Paragraph 0131-0136
(2013/10/08)
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- HYDROCARBOXYLATION OF FORMALDEHYDE IN THE PRESENCE OF A HIGHER ORDER CARBOXYLIC ACID AND HETEROGENEOUS CATALYST
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Disclosed is a process for the production and purification of glycolic acid or glycolic acid derivatives by the carbonylation of formaldehyde in the presence of a solid acid catalyst and a carboxylic acid. This invention discloses hydrocarboxylations and corresponding glycolic acid separations wherein the glycolic acid stream is readily removed from the carboxylic acid and the carboxylic acid is recycled.
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Paragraph 0137-0142
(2013/10/08)
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- HYDROCARBOXYLATION OF METHYLENE DIPROPIONATE IN THE PRESENCE OF A PROPIONIC ACID AND A HOMOGENEOUS CATALYST
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Disclosed is a process for the production and purification of glycolic acid or glycolic acid derivatives by the carbonylation of methylene dipropionate in the presence of a homogeneous acid catalyst and propionic acid. This invention discloses hydrocarboxylations and corresponding homogeneous acid catalyst and glycolic acid separations. The homogeneous acid catalyst is readily separated from the hydrocarboxylation reaction effluent and recycled and the propionic acid is readily removed from the glycolic acid and the propionic acid is recycled
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Paragraph 0151-0156
(2013/10/08)
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- HYDROCARBOXYLATION OF FORMALDEHYDE IN THE PRESENCE OF A HIGHER ORDER CARBOXYLIC ACID AND A HOMOGENEOUS CATALYST
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Disclosed is a process for the production and purification of glycolic acid or glycolic acid derivatives by the carbonylation of formaldehyde in the presence of a homogeneous acid catalyst and a carboxylic acid. This invention discloses hydrocarboxylations and corresponding homogeneous acid catalyst and glycolic acid separations. The homogeneous acid catalyst is readily separated from the hydrocarboxylation reaction effluent and recycled and the carboxylic acid is readily removed from the glycolic acid and the carboxylic acid is recycled.
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Paragraph 0142-0147
(2013/10/08)
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- Permeable, water soluble, non-irritating prodrugs of chemotherapeutic agents with oxaalkanoic acids
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The present invention relates to the field of prodrugs of chemotherapeutic agents and method of use thereof.
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- Methods to increase plasma HDL cholesterol levels and improve HDL functionality with probucol monoesters
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It has been discovered that certain selected probucol monoesters, and their pharmaceutically acceptable salts or prodrugs, are useful for increasing circulating HDL cholesterol. These compounds may also improve HDL functionality by (a) increasing clearance of cholesteryl esters, (b) increasing HDL-particle affinity for hepatic cell surface receptors or (c) increasing the half life of apoAI-HDL.
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- Condensation of Diglycolic Acid Dichloride with Polyglycols. 5. An Improved Synthesis of Cyclic Polyether-Esters by Cyclization
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An improved synthesis of oligocyclic (ether-ester)s by cyclization condensation of polyglycols with diglycolic acid dichloride in benzene/pyridine or dioxane/pyridine is reported. Keywords: Macrocyclic oligo(ether-ester)s
- Erk, Cakil
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p. 1083 - 1084
(2007/10/02)
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- Kinetics of Ru(III) Chloride Catalysed Oxidation of Di- and Tri-ethylene Glycols by Hexacyanoferrate(III)
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Kinetics of the title reactions in aq. alkaline medium and at constant ionic strength are reported.The oxidation reaction follows complex kinetics, the order being zero with respect to initial , nearly unity with respect to low concentration of substrates and zero at higher .The rate of reaction is inversely proportional to .A suitable mechanism involving the hydride ion transfer from the α-carbon atom of glycol by ruthenium(III) complex has been suggested.
- Singh, H. S.,Tiwari, K. C.,Singh, S. M.
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p. 520 - 522
(2007/10/02)
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- CHIRAL AMINOACID CONTAINING ACYCLIC LIGANDS-I. SYNTHESES AND CONFORMATIONS
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Synthesis and spectral properties of optically active acyclic ligands, containing two (S)-phenylalanine residues (3a-f) are described.The synthesis is achieved by two different routes.Conformational studies in different solvents are performed by dilution and temperature-dependent experiments of 1H and 13C NMR spectroscopy.
- Lodi, T.,Marchelli, R.,Dossena, A.,Dradi, E.,Casnati, G.
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p. 2055 - 2060
(2007/10/02)
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- OXIDATION OF ALCOHOLS BY ELECTROCHEMICALLY REGENERATED NICKEL OXIDE HYDROXIDE. SELECTIVE OXIDATION OF HYDROXYSTEROIDS
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Primary alcohols, α,ω-diols and secondary alcohols are easily transformed into carboxylic acids, dicarboxylic acids or ketones, respectively, by heterogeneous oxidation with nickel oxide hydroxide electrochemically regenerated at a nickel hydroxyde electrode.The results are discussed in comparison to those of the nickel peroxide and chromic acid oxidation.The oxidation rate decreases with increasing steric hindrance of the alcohol, thus allowing the selective oxidation of the 3-position in hydroxysteroids.
- Kaulen, Johannes,Schaefer, Hans-J.
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p. 3299 - 3308
(2007/10/02)
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- Extractive separation of glycolic acid from diglycolic acid
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Diglycolic acid is separated from glycolic acid by preferential extraction from an aqueous mixture of the two acids using an organic solution of a water-insoluble trihydrocarbylphosphine oxide as the extraction agent.
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- Process for preparing 1,4-dioxan-2-ones
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1,4-Dioxan-2-ones are prepared by contacting carbon monoxide with formaldehyde, a 1,2-glycol, and a catalytic amount of hydrogen fluoride. The products of this reaction are readily converted into diglycolic acids by heating with aqueous caustic in the presence of a nickel catalyst.
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- Acid production
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A process for producing hydroxyacetic acid which comprises contacting carbon monoxide with formaldehyde and a catalyst comprising hydrogen fluoride in a reaction zone at a temperature between 0° and 100° C and a pressure between 10 and 4000 psig. Oxydiacetic acid is also produced by this reaction. The ratio of hydroxyacetic acid to oxydiacetic acid is increased by adding water to the reaction mixture.
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- Process for the production of ether polycarboxylic acids
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A process for the production of ether polycarboxylic acids comprising reacting alkali metal salts of ether carboxylic acids with carbon dioxide in the presence of a silicon compound selected from the group of alkali metal alkoxy-silanolates and alkali metal alkoxy-polysiloxanolates and, optionally, inert diluents at temperatures of 200° to 350°C under pressure, acidify the resulting alkali metal salt of an ether polycarboxylic acid and recovering said ether polycarboxylic acid.
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- Process for preparing diglycolic acid
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Diglycolic acid is prepared by oxidation of p-dioxanone.
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