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Showing papers on "Carboxylic acid published in 1975"


Journal ArticleDOI
TL;DR: The finding that transferrin does not bind Fe3+ at the specific metal binding sites in the absence of carbonate and synergistic anions emphasizes the fundamental importance of the anion binding site to the chemistry of Fe3-transferrin-CO32-.

268 citations


Journal ArticleDOI
TL;DR: In this article, an interpolymer complex was prepared by mixing aqueous solutions of poly(ethylene oxide) (PEO) and of a poly(carboxylic acid), i.e., poly(acrylic acid)(PAA), poly(methacric acrylic acid)(PMAA), or styrene-maleic acid copolymer(PSMA).
Abstract: An interpolymer complex was prepared by mixing aqueous solutions of poly(ethylene oxide) (PEO) and of a poly(carboxylic acid), i.e., poly(acrylic acid)(PAA), poly(methacrylic acid)(PMAA), or styrene-maleic acid copolymer(PSMA). The complexation mechanism was discussed on the basis of results of such experimental methods as viscosity, potentiometric titration, and turbidimetry. The hydrogen bond is primarily involved in these complexations, but the influence of hydrophobic interaction on complexation can not be ignored. If the degree of dissociation α of carboxylic acid or the degree of polymerization Pn of PEO was perceptibly changed, a stable complex was obtained at about α 0.1 or Pn(PEO) = 40 for PMAA, 200 for PAA. This fact indicates that more than a definite number of binding sites are necessary for a stable interpolymer complex to be formed and that cooperative interaction among active sites plays an important role in complex formation.

160 citations



Journal ArticleDOI
TL;DR: Several lines of evidence suggest that the entry of organic anions cannot be ascribed to simple diffusion across aqueous channels limited by positive charges but needs a specific interaction of the penetrating anion with a component of the membrane.
Abstract: 1. The penetration of organic anions into bovine red blood cells has been studied under experimental conditions where it could be distinguished from the penetration of undissociated acids which proceeds by diffusion through lipid zones of the membrane. 2. Several lines of evidence suggest that the entry of organic anions cannot be ascribed to simple diffusion across aqueous channels limited by positive charges but needs a specific interaction of the penetrating anion with a component of the membrane. 3. The structural requirements allowing for ionic transfer is a strong polar head for the smallest molecules and in addition an amphiphilic structure for acids with chain length greater than C4. Interaction between substrate and receptor requires at least a three point attachment involving three oxygen atoms in the substrate which react with complementary loci on the receptor to form ionic and hydrogen bonds. Such a three point attachment can be made by a sulphonic group or with carboxylic acid by alpha ketosubstitution, alpha hydroxysubstitution, addition of an amidegroup or addition of a second carboxyl group spatially close to the first. 4. As suggested by the behaviour of the formate anion, in such a transport system any carboxylic acid could interact transiently with the receptor and therefore interfere with the transport of an organic anion even though such ionic interaction with the receptor were insufficient to produce transport of the acid itself.

107 citations


Patent
24 Jul 1975
TL;DR: In this paper, a method for the preparation of relief structures of highly heat-resistant polymers, using radiation-sensitive, soluble preliminary polymers in the form of polyaddition or polycondensation products of polyfunctional carbocyclic or heter-cyclic compounds containing radiation-reactive radicals in ester groups bound to said compounds with diamines, diisocyanates, bis-acid chlorides or dicarboxylic acids of cyclic structure.
Abstract: The invention provides a method for the preparation of relief structures of highly heat-resistant polymers, using radiation-sensitive, soluble preliminary polymers in the form of polyaddition or polycondensation products of polyfunctional carbocyclic or heterocyclic compounds containing radiation-sensitive radicals in ester groups bound to said compounds with diamines, diisocyanates, bis-acid chlorides or dicarboxylic acids of cyclic structure. According to the invention, the polyfunctional compounds containing the radiation-sensitive radicals contain, besides carboxyl, carboxylic acid chloride, amino, isocyanate or hydroxyl groups suitable for addition or condensation reactions, partly in ortho or peri-position thereto, radiation-reactive radicals in the ester groups bound to the compounds having an oxyalkylene methacrylate or acrylate structure.

96 citations


Journal ArticleDOI
TL;DR: The E. coli CoA-transferase is partially inactivated by acyl-CoA substrates in the absence of carboxylic acid substrates, presumably as the result of a metal-catalyzed acylation of the ϵ-amino group of a lysine residue near the active site.

95 citations


Journal ArticleDOI
TL;DR: A spectrofluorometric assay for 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid has been developed, the compound is 95–100% stable for 2 months at room temperature and 45 C, and a low level of toxicity is found.
Abstract: 6-Hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid in thin layer tests in vegetable oils and animal fats has two-four times the antioxidant activity of butylated hydroxytoluene and butylated hydroxyanisole and is more active than propyl gallate, nordihydroquaiaretic acid, ascorbyl palmitate, and α- and γ-tocopherols. It is also more active than tertiary butylhydroquinone in chicken and pork fats and corn, peanut, sunflower, and safflower oils in thin layer tests. Tertiary butylhydroquinone is slightly more active in corn, soybean, cottonseed, and peanut oils in the active oxygen method, probably due to decomposition of the chroman at 98 C. This decomposition is inhibited by ascorbic acid. The chroman is synergized by ascorbyl palmitate-thiodipropionate and ascorbic acids. Active oxygen method values of 190 hr are obtained in combination with the latter. A spectrofluorometric assay for 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid has been developed. The compound is 95–100% stable for 2 months at room temperature and 45 C, and a low level of toxicity is found. The copper and iron breakdown products of the chroman have been determined. A possible relationship between these products, protection of the chroman by ascorbic acid and ethylene diaminetetraacetic acid, and a mechanism of action is presented.

78 citations


Patent
28 Jan 1975
TL;DR: Water-swellable, cross-linked, bead copolymers of an ethylenically unsaturated monomer having a carboxylic acid anhydride, glycidyl or succinimide group are disclosed to be excellent carriers capable of bonding with biologically active substances such as enzymes, enzyme substrates, inhibitors, hormones, antibiotics, antigens, and peptides.
Abstract: Water-swellable, cross-linked, bead copolymers of (A) an ethylenically unsaturated monomer having a carboxylic acid anhydride, glycidyl or succinimide group, (B) a comonomer having at least two radical-polymerizable carbon double bonds, and (C) a radical-polymerizable water-soluble comonomer are disclosed to be excellent carriers capable of bonding with biologically active substances such as enzymes, enzyme substrates, inhibitors, hormones, antibiotics, antigens, and peptides.

74 citations


Journal ArticleDOI
TL;DR: Mixtures of porphyrins derived from natural sources can be readily separated by high-pressure liquid chromatography both analytically and on a preparative scale, and this provides not only a rapid qualitative assessment of the components of a mixture, but also a check on the subsequent chromatographic separations.

73 citations


Journal ArticleDOI
TL;DR: The ester, amide, and uronate contents of pectins and the uronates content of alginates were determined from the ester-carbonyl stretching band, the amide I band, and the carboxylate antisymmetric stretching band obtained from the spectra of solutions in D2O-phosphate buffer.

72 citations


Patent
11 Mar 1975
TL;DR: Improved copolymers of unsaturated copolymerizable carboxylic acid monomers and one or more alkyl acrylate esters containing 10 to 30 carbon atoms which serve as efficient thickeners of aqueous solutions, even in the presence of substantial amounts of inorganic salts such as sodium chloride are prepared by conducting the polymerization of the comonomers in a chlorofluoroethane as discussed by the authors.
Abstract: Improved copolymers of unsaturated copolymerizable carboxylic acid monomers and one or more alkyl acrylate esters containing 10 to 30 carbon atoms which serve as efficient thickeners of aqueous solutions, even in the presence of substantial amounts of inorganic salts such as sodium chloride are prepared by conducting the polymerization of the comonomers in a chlorofluoroethane.

Patent
10 Feb 1975
TL;DR: 1,4-Dihydropyridines characterized by alkyl groups in 2-and 6-positions, a pyridyl group in 4-position, a carboxylate in 5-position and an aminoalkyl CARB in 3 position, demonstrate coronary vessel dilation and anti-hypertensive effects as mentioned in this paper.
Abstract: 1,4-Dihydropyridines characterized by alkyl groups in 2- and 6-positions, a pyridyl group in 4-position, a carboxylate in 5-position and an aminoalkyl carboxylate group in 3 position, demonstrate coronary vessel dilation and anti-hypertensive effects.

Patent
04 Dec 1975
TL;DR: The (6-hydroxy-chroman-2-yl) acetic or carboxylic acid derivatives useful as antioxidants and a method for preparing these derivatives from hydroquinones and intermediates in this synthesis as well as the use of these derivatives as intermediate in the preparation of optically active alpha-tocopherol were discussed in this paper.
Abstract: The (6-hydroxy-chroman-2-yl) acetic or carboxylic acid derivatives useful as antioxidants and a method for preparing these derivatives from hydroquinones and intermediates in this synthesis as well as the use of these derivatives as intermediates in the preparation of optically active alpha-tocopherol.

Patent
17 Jul 1975
TL;DR: Topical dermatological compositions containing acylamino-carboxylic acid compounds of the formula "STR1" are given in this paper, where R1 is hydrogen, alkyl of 1 to 3 carbon atoms, trifluoromethyl, phenyl, halophenyl, nitro-phenyl or biphenylyl.
Abstract: Topical dermatological compositions containing an acylamino-carboxylic acid compound of the formula ##STR1## wherein R1 is hydrogen, alkyl of 1 to 3 carbon atoms, trifluoromethyl, phenyl, halo-phenyl, nitro-phenyl or biphenylyl, R2 is hydrogen or alkyl of 1 to 3 carbon atoms, R3 is hydrogen, alkyl of 1 to 6 carbon atoms, methylthio-(alkyl of 1 to 6 carbon atoms) or benzyl, R4 is alkyl of 10 to 22 carbon atoms, n is 0, 1 or 2, R5 is alkyl of 8 to 22 carbon atoms, phenyl or biphenylyl, and R6 is hydrogen or alkyl of 1 to 3 carbon atoms; the compositions are useful for the care of the skin.

Patent
Ralf Steinsträsser1
24 Jun 1975
TL;DR: In this article, it was shown that a straight-chain alkyl or alkoxy of 1-7 carbon atoms can be produced by reacting a phenol of the general formula with an aromatic carboxylic acid.
Abstract: Compounds of the general formula ##STR1## wherein n is 0, 1 or 2, R 1 is straight-chain alkyl or alkoxy of 1-7 carbon atoms or straight-chain alkanoyloxy of 2-7 carbon atoms, and R 2 is straight-chain alkyl or alkoxy of 1-7 carbon atoms with the proviso that when n is 0, R 1 and R 2 together contain at least 4 carbon atoms, which form nematic phases, can be produced by reacting a phenol of the general formula ##STR2## WHEREIN R 2 has the values given above, and p is 0, 1 or 2 or a corresponding phenolate, with an aromatic carboxylic acid of the general formula ##STR3## WHEREIN R 1 has the values given above, and q is 0, 1 or 2, and the sum p + q is n, or with a reactive derivative of this acid.

Journal ArticleDOI
TL;DR: In this article, the authors used the Alcali-labile protecting groups to protect α-melanotropin and partial sequences for biological investigations in as pure a state as possible.
Abstract: Hormone-Receptor Interactions. Synthesses of α-Melanotropin and of Informational Sequences thereof with the Aid of Alcali-Labile Protecting Groups. The aim of this investigation was to prepare α-melanotropin and partial sequences thereof for biological investigations in as pure a state as possible. Classical synthesis in solution was chosen as the general approach, because it allows for extensive purification and identification of all intermediates, thus warranting the chemical identity of the products (in contrast to the solidphase methods). The scheme of protection was as follows: for the Nα-amino groups mostly t-butoxycarbonyl (BOC-), sometimes benzyloxycarbonyl (Z-), for the Nϵ-amino group of lysine-(11) 2-(methylsulfonyl)-ethoxycarbonyl (MSOC-), and for the carboxylic acid group of C-terminal glycine-(10) 2-(4-tolyl-sulfonyl)-ethoxy (-OTSE). This provides for facile and mild selective deprotection of either the α-amino groups by acidolysis or of the ϵ-amino group (α-carboxyl group) by β-elimination in alcali. A slight molar excess of 0.12N HCl in HCOOH proved to be the method of choice for removing BOC-; MSOC- is stable in acid (even for 30 min in liquid HF) and easily removed in a few minutes by 0.05--0.1N Ba(OH)2; -OTSE is removed similarly. Condensation of amino-acid and peptide derivatives (formation of the peptide link) was performed using active esters (-ONP; -OSU), dicyclohexyl-carbodiimide (DCCI) with or without 1-hydroxy-benzotriazole (HOBT), or carboxylic acid azides wherever histidine was the carboxylic component. More than 50 compounds are described. Those characterized by arabic numerals served to prove that α-MSH contains two message sequences that are able to trigger melanocyte response: one in the central region -His-Phe-Arg-Trp-, the other in the C-terminal portion -Gly-Lys-Pro-Val · NH2 of the molecule [3].

Patent
02 May 1975
TL;DR: The various isomers of oxazolo- and thiazolopyridines having utility as antiinflammatory, antipyretic and analgesic agents are prepared by condensation of an appropriate amino-hydroxypyridine or amino-mercaptopyridine with a carboxylic acid, halide or anhydride as discussed by the authors.
Abstract: The various isomers of oxazolo- and thiazolopyridines having utility as antiinflammatory, antipyretic and analgesic agents are prepared by condensation of an appropriate amino-hydroxypyridine or amino-mercaptopyridine with a carboxylic acid, halide or anhydride.

Journal ArticleDOI
TL;DR: The synthesis, microbiological profile and in vivo effectiveness in laboratory animals of a series of cephalosporins having 7-acyl substituents derived from methylthioacetic acid are described, and one derivative, 7-trifluoromethylthioacetamido-3-cephem-4-carboxylic acid, was found to have outstanding antibacterial activity in vitro and in vitro.
Abstract: The synthesis, microbiological profile and in vivo effectiveness in laboratory animals of a series of cephalosporins having 7-acyl substituents derived from methylthioacetic acid are described. Structure-activity relationships examined include the effect of oxidation of the side-chain sulfur atom, replacement of the (side-chain) methyl hydrogens by fluorine and replacement of the 3-acetoxy substituent by thioheterocycles. One derivative, 7-trifluoromethylthioacetamido-3-(1-methyl-1H-tetrazol-5-ylthiomethyl)-3-cephem-4-carboxylic acid (SK&F 59962), was found to have outstanding antibacterial activity in vitro and in vivo.

Patent
02 Jun 1975
TL;DR: In this article, a modified polyolefin having high adhesion strength and less irritating odor during processing is obtained by reacting unsaturated carboxylic acid or its anhydride grafted polyolefins with a bifunctional compound having alcohol groups or amine groups.
Abstract: Modified polyolefin having high adhesion strength and less irritating odor during processing is obtained by reacting unsaturated carboxylic acid or its anhydride grafted polyolefin with a bifunctional compound having alcohol groups or amine groups. Preferable unsaturated carboxylic acids are maleic acid, and endobicyclo-[2,2,1]-5-heptene-2,3-dicarboxylic acid. Preferable bifunctional compounds are ethylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerine, ethylene diamine, 1,3-diaminopropane m-phenylene diamine, etc.

Patent
07 Feb 1975
TL;DR: In this paper, aldehydes or ketones are selectively oxidized by hydrogen peroxide to the corresponding azines when they are reacted in the presence of both an amide of a carboxylic acid having a pK greater than about 4.3 and a co-catalyst having the general formula H--X--Y=Z, wherein H is hydrogen, X and Z are each atom of oxygen or nitrogen and Y is an atom of carbon, nitrogen, arsenic, antimony, phosphorus, sulfur, selenium or tellurium; the atoms
Abstract: Ammonia and aldehydes or ketones are selectively oxidized by hydrogen peroxide to the corresponding azines when they are reacted in the presence of both (a) an amide of a carboxylic acid having a pK greater than about 4.3 and (b) a co-catalyst having the general formula H--X--Y=Z, wherein H is hydrogen, X and Z are each an atom of oxygen or nitrogen and Y is an atom of carbon, nitrogen, arsenic, antimony, phosphorus, sulfur, selenium or tellurium; the atoms of X, Y, and Z carrying other substituents necessary to obey the rules of valence. Preferred co-catalysts include di(alkali metal) hydrogen phosphates, lower dialkyl phosphate esters, bicarbonates and p-toluene sulfonic acid. When 1° or 2° amines are also present, hydrazones are also formed along with the azines. Uses of the resultant products include their hydrolysis to hydrazines with recycling of aldehyde or ketone.


Journal ArticleDOI
03 Jul 1975-Nature
TL;DR: In bacterial photosynthesis, reductive CO2 fixation was thought to proceed through activation of carboxylic acid by coenzyme A followed by the reductive incorporation of CO2 in the presence of reduced ferredoxin.
Abstract: IN bacterial photosynthesis, reductive CO2 fixation was thought to proceed through activation of carboxylic acid by coenzyme A followed by the reductive incorporation of CO2 in the presence of reduced ferredoxin (a kind of non-haem iron–sulphur protein) and an enzyme, pyruvate synthase, as shown in equation (1). The reaction takes place in vitro in the same way using CoA, reduced ferredoxin and pyruvate synthase1.

Journal ArticleDOI
TL;DR: The present results suggest that the physiologically active conformation of GABA is the fully extended molecule, and additionally indicate that one dimension of the postsynaptic receptor site is within the range of 4.2 to 4.8 ångströms.
Abstract: 1 Pyramidal cells in rat hippocampus were used to study the molecular dimensions of a receptor for inhibitory amino acids in the central nervous system. The inhibitory potencies of γ-aminobutyrate (GABA), β-alanine and glycine were compared by standard microiontophoretic techniques. Subsequently, rigid cyclopentane and cyclohexane amino acid analogues were applied by iontophoresis and their relative efficacies were compared with those of the naturally occurring amino acids. 2 GABA was the most effective of the small aliphatic amino acids in producing inhibition of the firing of hippocampal pyramidal neurones. β-Alanine was less effective and glycine was the least effective. GABA-induced inhibition was antagonized by concurrent iontophoresis of picrotoxin or bicuculline, whereas strychnine did not antagonize GABA inhibition. 3 The ability of the series of substituted aminocyclopentane and aminocyclohexane carboxylic acids to produce inhibition of pyramidal cells was a direct function of the separation of amino and carboxylic acid groups. In both series of the cyclic amino acids the most potent inhibition was demonstrated when the spatial separation was similar to that of the extended GABA molecule (4.74 A). Additionally, the inhibition of hippocampal pyramidal cells by (±-cis-3-amino-cyclopentanecarboxylic acid, like that produced by GABA, could be blocked by simultaneous application of picrotoxin or bicuculline, but not by strychnine. 4 The present results suggest that the physiologically active conformation of GABA is the fully extended molecule, and additionally indicate that one dimension of the postsynaptic receptor site is within the range of 4.2 to 4.8 angstroms.

Journal ArticleDOI
TL;DR: Microsomal esterases of mouse and rat liver readily cleave the trans - but not the cis -isomers of resmethrin (5-benzyl-3-furylmethyl chrysanthemate) and these findings confirm in vivo studies on the isomeric variations in metabolism of the res methrin components.

Journal ArticleDOI
TL;DR: The characteristics of the enzyme Delta(1)-pyrroline-5-carboxylic acid dehydrogenase from etiolated barley (Hordeum distichum) shoots have been examined, and activity was NAD-dependent.
Abstract: The characteristics of the enzyme Δ1-pyrroline-5-carboxylic acid dehydrogenase from etiolated barley (Hordeum distichum) shoots have been examined. The bulk of the enzyme activity was found in the 10,000g pellet fraction, this activity being displayed only after detergent treatment of the suspended pellet. The enzyme was most active at pH 8, and activity was NAD-dependent. Enzyme activity was unaffected by either mannitol or sucrose in the reaction mixture up to a concentration of 0.45 m but was strongly inhibited by Cl− and, to a lesser extent, SO42−. The inhibition attributable to KCl was reversed by increasing the concentration of Δ1-pyrroline-5-carboxylic acid in the reaction mixture.

Patent
22 Dec 1975
TL;DR: In this paper, a carboxylic acid anhydride, such as acetic anhydrides, is prepared from a caroxylate ester or a hydrocarbyl ether in carbonylation processes.
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.

Journal ArticleDOI
TL;DR: The physico-chemical properties of the isolated N-acetyl-TTCA were identical in all respects to an authentic, chemically-synthesized product, prepared by reacting D-penicillamine with acetaldehyde to form TTCA and then acetylating this product with acetic anhydride.

Patent
Nakamura Tetsuya1
16 Jul 1975
TL;DR: Aliphatic carboxylic acid esters of Vitamin E have been studied in this paper where the aliphatic CARB moiety is branched at the α-position.
Abstract: Aliphatic carboxylic acid esters of Vitamin E wherein the aliphatic carboxylic acid ester moiety is branched at the α-position. The compounds exhibit the biological activities of Vitamin E for a long time.

Patent
04 Nov 1975
TL;DR: In this article, an improved method for removing carboxylic acid contaminants from aqueous effluents or recycle streams is provided, which is based on the extraction of mono or dicarboxyric acids from dilute solutions with an organic liquid comprising one or more of the following extractants: dialkyl alkyl phosphonates, alkylin dialkyls phosphinates, trialkyl phosphine oxides, dialkylin alicyclic amidophosphates and tetralkyl ureas.
Abstract: Mono or dicarboxylic acids containing from two to four carbon atoms are extracted from dilute aqueous solutions with an organic liquid comprising one or more of the following extractants: dialkyl alkyl phosphonates, alkyl dialkyl phosphinates, trialkyl phosphine oxides, dialkyl alicyclic amidophosphates, dialkyl sulfoxides and tetralkyl ureas. An improved method for removing carboxylic acid contaminants from aqueous effluents or recycle streams is provided.

Patent
09 Oct 1975
TL;DR: In this article, insoluble crosslinked polymeric microparticles are added to solutions or dispersions of carboxylic acid amide interpolymers to improve film build, pattern control and flow control.
Abstract: Coating compositions having improved application characteristics as well as other desirable properties are prepared by adding insoluble crosslinked polymeric microparticles to solutions or dispersions of carboxylic acid amide interpolymers. The compositions may be spray coated onto various substrates in two coat applications to form coatings having improved film build, pattern control and flow control while maintaining the gloss characteristics of the film.