Showing papers on "Carboxylic acid published in 1984"

Process for the preparation of polyketones

Abstract: A process for the preparation of polyketones by polymerizing a mixture of CO and an alkenically unsaturated hydrocarbon in the presence of a Group VIII metal catalyst containing ligands, which comprise hydrocarbon groups that are bonded to an element from groub Vb, characterized in that, as catalyst, a complex compound is used that is obtained by reacting a palladium, cobalt or nickel compound, an anion of an acid with a pKa of less than 2, provided it is neither a hydrohalogenic acid nor carboxylic acid and a bidentate ligand of the general formula R 1 R 2 -M-R-M-R 3 R 4 , in which M represents phosphorus, arsenic or antimony, R represents a divalent organic bridging group having at least two carbon atoms in which the bridge, none of these carbon atoms carrying substituents that may cause steric hindrance and in which R 1 , R 2 , R 3 and R 4 are identical or different hydrocarbon groups.

Bestimmung des Aggregationsgrads lithiumorganischer Verbindungen durch Kryoskopie in Tetrahydrofuran

Abstract: Degree of Aggregation of Organolithium Compounds by Means of Cryoscopy in Tetrahydrofuran The association behaviour of alkyl-, aryl- and alkinyl-lithium compounds as well as of lithium enolates and chiral lithium azaenolates is determined from freezing-point depression values in dilute tetrahydrofuran solutions at −108°C. Compared toX-ray-crystallographic data (lithiated methyldithiane, phenyllithium, lithio derivatives of a ketone, carboxylic amide and -ester, and a diketopiperazine-bislactim-ether), desaggregation is found under these conditions. The structures determined by 13C-NMR spectroscopy for BuLi, lithiophenylacetylene and (t-butyl)lithioacetylene are confirmed. The dilithio salt of a carboxylic acid is polymeric, a chiral lithio-hydrazone and a chiral lithio-oxazolidine are monomeric and dimeric, respectively. Lithium diisopropylamide is a monomer-dimer equilibrium mixture. The apparatus described permits both synthesis and measurement of the reactive species under inert atmosphere conditions in the same vessel.

pH-Dependent complexation of poly(acrylic acid) derivatives with phospholipid vesicle membranes

Abstract: Poly(acrylic acid), poly(methacrylic acid), and poly(α-ethylacrylic acid) can be used to modify, in a pH-dependent manner, the properties of phospholipid vesicle membranes. Polymer-lipid complexation caw a decrease in the apparent cooperativity of the lipid melting transition. The "critical pH" for complexation may be controlled through variation of the chemical structure and the tacticity of the poly(carboxylic acid), It is suggested that an important driving force for complexation is provided by the formation of hydrogen bonds between un-ionized carboxyl groups of the polymer and the phosphodiester functions of the lipid surface.

Heterogeneous photocatalytic reactions of organic acids and water. New reaction paths besides the photo-Kolbe reaction

Abstract: The heterogeneous photocatalytic reactions of acetic, propionic, and butyric acids were studied on several kinds of powdered semiconductors, mainly TiO/sub 2/. The influence of Ag/sup +/ as an electron acceptor, and the dependence of the reactions on the kind of semiconductor and pH, were investigated. The ratio of yields of hydrogen to hydrocarbon depends strongly on pH. At neutral or alkaline pH, hydrocarbon stops being evolved and only hydrogen is evolved. It is concluded that the pH dependence of the valence band position of the semiconductor and the concentration of OH/sup -/ ion control the reaction paths. From the pH dependence of methane production from acetic acid the valence band of anatase is estimated to be located more deeply by 0.1 eV than that of rutile. The results of product analysis and the complete decomposition of acetic acid to CO/sub 2/ show that there exist new reaction paths in which water is an oxidizing agent. Reaction schemes of these organic acids are proposed.

Ethylene copolymer viscosity index improver-dispersant additive useful in oil compositions

Abstract: Oil soluble viscosity index improving ethylene copolymers, such as copolymers of ethylene and propylene; and ethylene, propylene and diolefin; etc., are reacted or grafted with ethylenically unsaturated carboxylic acid moieties, preferably maleic anhydride moieties, and reacted with polyamines having two or more primary amine groups and a carboxylic acid component, preferably alkylene polyamine and alkenyl succinic anhydride such as polyisobutenyl succinic anhydride. Or the grafted ethylene copolymer can be reacted with already formed salts, amides, imides, etc. of said polyamine and acid component, preferably imides of alkylene polyamine and alkenyl succinic anhydride. These reactions can permit the incorporation of varnish inhibition and dispersancy into the ethylene copolymer while inhibiting cross-linking with resulting viscosity increase, haze or gelling. The aforesaid grafting reaction may be carried out thermally, or more preferably with a free radical initiator such as a peroxide in a mineral lubricating oil, in which case the acid component, preferably also acts to solubilize insoluble compounds formed by side reactions, such as maleic anhydride grafted oil molecules reacted with amine, to thereby inhibit haze formation, particularly when preparing oil concentrates of the V.I.-dispersant additive for later addition to lubricating oils. The invention also includes preferred methods of grafting maleic anhydride onto the ethylene copolymer by periodic or continuous addition of maleic anhydride and initiator charge, so as to maintain the maleic anhydride in solution during the grafting reaction.

Studies on Prodrugs of Cephalosporins. I. Synthesis and Biological Properties of Glycyloxybenzoyloxymethyl and Glycylaminobenzoyloxymethyl Esters of 7β-[2-(2-Aminothiazol-4-yl)-(Z)-2-methoxyiminoacetamido]-3-methyl-3-cephem-4-carboxylic Acid

Abstract: p-Glycyloxy-, o-glycylamino- and p-glycylaminobenzoyloxymethyl esters of 7β-[2-(2-aminothiazol-4-yl)-(Z)-2-methoxyiminoacetamido]-3-methyl-3-cephem-4-carboxylic acid (1) were synthesized as prodrugs designed to improve the oral absorption of the parent cephalosporin. The esters were found to possess the desired factors for an orally active prodrug, that is, appropriate solubility, lipophilicity and lability. As predicted from these factors, the esters when administered orally to mice were well absorbed from the gastrointestinal tract and gave high blood levels of the parent compound (1).

Synthesis of isocoumarins via thallation-olefination of benzoic acids

Abstract: Par thallation de l'acide benzoique puis alcenylation en presence de PdCl 2 du carboxy-2 phenyl bis-trifluoroacetoxy thallium obtenu, on prepare diverses isocoumarines et dihydro-3,4 isocoumarines

Axially dissymmetric bis(aminophosphine)s derived from 2,2'-diamino-1,1'-binaphthyl. Synthesis and application to rhodium(I)-catalyzed asymmetric hydrogenations.

Abstract: Axially dissymmetric bisphosphine ligands, (R)- and (S)-2,2′-bis(diphenylphosphinoamino)-1,1′-binaphthyl (BDPAB) and (R)-2,2′-bis[N-(diphenylphosphino)methylamino]-1,1′-binaphthyl (Me-BDPAB) were conveniently prepared from 2,2′-diamino-1,1′-binaphthyl The rhodium(I)-catalyzed asymmetric hydrogenation of α-acylamidoacrylic acids and esters gave the corresponding amino acids of up to 95% optical purity The sign of the centro-chirality of the product amino acids was always the same to that of the axial chirality of the ligand in both cases of BDPAB and Me-BDPAB

Bleach compositions comprising non-linear aliphatic peroxycarboxylic acid precursors

Abstract: Detergent compositions, detergent additive products and bleaching compositions containing aliphatic peroxyacid bleach precursors of formula ##STR1## are provided, where L is a leaving group of defined formula whose conjugate acid has a pKa of from 6 to 13 and ##STR2## is a non linear acyl group, the carboxylic acid derivative of which has a logPOCT in the range from 1.9 to 4.0 (where POCT is the partition coefficient between octanol and water). New precursor compounds are provided in which ##STR3## is a C7 -C17 branched aliphatic acyl group containing a linear chain of at least 5 carbon atoms extending from and including the carbonyl carbon wherein the branching is on at least the 2- and/or 3- carbon atom.

Photosensitive polymer composition

Abstract: PURPOSE: Titled composition which has good film-forming properties and provides patterns having excellent picture characteristics, comprising an organic polar solvent and a specified photosensitive polyamide acid condensate prepared from a photosensitive diamine compound and a carboxylic acid anhydride. CONSTITUTION: The photosensitive polymer composition is prepared by reacting a first component consisting of 100W5wt% of a photosensitive group-containing diamine compound represented by formula I, wherein R 1 is a trivalent or tetravalent 2C or higher group, R 2 is a photosensitive group and X is H or Y-R 2 (Y is -O- or -CH 2 O-) and 0W95wt% of a diamine compound represented by formula II, wherein R 3 is a bivalent 2C or higher group, with a second component consisting of a tetracarboxylic acid dianhydride represented by formula III, wherein R 4 is a tetravalent 4C or higher group, and/or a tricarboxylic acid anhydride monochloride represented by formula IV, wherein R 5 is a trivalent 2C or higher group and Z is a halogen, in an organic polar solvent such as N-methyl-2-pyrrolidone to form a photosensitive polyamide acid condensate (intrinsic viscosity≤0.1). COPYRIGHT: (C)1981,JPO&Japio

Oxetin, a new antimetabolite from an actinomycete. Fermentation, isolation, structure and biological activity.

Abstract: A new amino acid-antimetabolite, oxetin, was isolated from a fermetation broth of a Streptomycesp .s OM-2317, a soil isolate, The chemical structure was elucidated as(2R, 3S)-3-amino-2-oxetane carboxylic acid by analysis of the spectral data and by X-ray diffraction methods. The antibiotic is the first natural product possessing an oxetane ring. Certain microorganisms were inhibited by oxetin only when cultivated in minimal media. The inhibitory action was reversed by several amino acids such as L-isoleucine, L-methionine, L-valine and L-glutamine. It also exhibited herbicidal activity and inhibited glutamine synthetase from spinach leaves.

Carboxylic acid derivatives useful for inhibiting the degradation of cartilage

Abstract: Certain carboxylic acids of the formula and the pharmaceutically-acceptable salts thereof, and certain esters and amides thereof, are useful for inhibiting the degradation of articular cartilage when administered to a mammalian subject afflicted with an arthritic disease X is O, S,SO, S0 2 , NH, NCH 3 or NCOCH 3 ; R 1 is H or CH 3 ; and n is zero or one

Vapor phase carbonylation of methanol with solid acid catalysts.

Abstract: Vapor phase carbonylation of methanol was catalyzed by strong solid acids in the absence of halogen promoter under pressurized conditions. Methyl acetate, methyl formate and acetic acid were obtained as carbonylated product with dimethyl ether as main by product. Hydrocarbons were also formed at high temperature.

Catalytic conversion of fluoroalkyl alkyl ethers to carbonyl compounds

Abstract: Conversion en presence de SbF 5 des ([hydryl-2 perfluoroalkyl] methyl) ethers et de [methyl perfluoroalcene-1 yl] ethers en fluorures d'acyle, cetones, cetoesters, enones et cetenes fluores

The structure and absolute stereochemistry of zincophorin (antibiotic m144255): a monobasic carboxylic acid ionophore having a remarkable specificity for divalent cations

Abstract: phores with ruminant growth promoting properties, we have previously reportcd the structure of antibiotic M1396032), the行rst tetronic acidcontainillg polyether. We now wish to describe antibiotic M144255, a monocarboxylic acid type ionophore from a strain of Streptomyces griseus. It has a high affinity fbr divalent cations especially zinc, for which reason it was given the trivial name, zincophorin. The molecular structure and absolute stereochemistry(Fig.1)were determined by X-ray analysis on the mixed zincInagnesium salt(see below)1). Although zinco.

Dispersion of kaolinite by dissolved organic matter from douglas-fir roots

Abstract: The organic constituents of water extracts from Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) roots that cause kaolinite dispersion were investigated. The dissolved organic matter was fractionated according to molecular size and chemical characteristics into acids, neutrals, and bases of the hydrophilic and hydrophobic groups. The dominant fraction causing dispersion included the hydrophobic acids and organics with molecular sizes greater than 104 nominal molecular weight. Partial oxidation of the dissolved organic matter increased its carboxylic acid content and dispersion potential. Organic acids promoting kaolinite dispersion included aliphatic and aromatic carboxylic acids. The dispersing ability of a carboxylic acid was related to its charge and charge density. Kaolinite has a pH-dependent surface charge; specific adsorption of carboxyl groups makes the clay more negative and promotes dispersion. Polycarboxylic acids appear to play the major role in kaolinite dispersion by dissolv...

Ascorbate interference-resistant composition, device and method for the determination of peroxidatively active substances

Abstract: A composition, test means (and device) and method for determining peroxidatively active substances in a test sample are disclosed. The composition, test means (and device) and method are rendered resistant to the adverse affects of ascorbate which may be present in the sample by the inclusion in the composition of a metal chelate which is polycarboxyalkylamine derivative having the formula: ##STR1## where: (a) R1 is hydrogen or straight or branched chain alkyl alcohol or alkyl carboxylic acid radicals having from 2 to 3 carbon atoms; R2, R3, Rx and Ry, same or different, are straight or branched chain alkyl alcohol or alkyl carboxylic acid radicals having from 2 to 3 carbon atoms; where at least two of R1, R2, R3, Rx or Ry are alkyl carboxylic acid radicals so defined; (b) Rp and Rq, same or different, are straight or branched chain alkylene radicals having from 1 to 3 carbon atoms or divalent 1,2-cycloaliphatic radicals having from 6 to 9 carbon atoms; (c) n is an integer having a value of from 0 to 1; m is an integer having a value of from 0 to 2; where if m is greater than 0, repeated Rp and repeated Rq radicals may be the same or different; and (d) M is Fe+3. The composition also comprises an organic hydroperoxide and an indicator capable of providing a detectable response in the presence of peroxide and the peroxidatively active substance. The test means comprises a carrier matrix incorporated with the composition, and the method comprises immersing the test means (or device) in the test sample and observing a color or other detectable response.