- Three new oxylipids related to 3,6-dioxo-4-docosenoic acid from Okinawan marine sponges, Plakortis spp.
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Manzamenones J (1) and K (2) and plakoridine B (3), three new oxylipins with unique carbon-skeletons related to 3,6-dioxo-4-docosenoic acid, were isolated from Okinawan marine sponges, Plakortis spp., and their structures elucidated on the basis of spectral and chemical means. Absolute stereochemistry of manzamenone A (4) was investigated by applying the modified Mosher's method developed recently for secondary carboxylic acids by Kusumi.
- Takeuchi,Kikuchi,Tsukamoto,Ishibashi,Kobayashi
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Read Online
- Ruthenium-on-Carbon-Catalyzed Facile Solvent-Free Oxidation of Alcohols: Efficient Progress under Solid-Solid (Liquid)-Gas Conditions
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A protocol for the ruthenium-on-carbon (Ru/C)-catalyzed solvent-free oxidation of alcohols, which proceeds efficiently under solid-solid (liquid)-gas conditions, was developed. Various primary and secondary alcohols were transformed to corresponding aldehydes and ketones in moderate to excellent isolated yields by simply stirring in the presence of 10% Ru/C under air or oxygen conditions. The solvent-free oxidation reactions proceeded efficiently regardless of the solid or liquid state of the substrates and reagents and could be applied to gram-scale synthesis without loss of the reaction efficiency. Furthermore, the catalytic activity of Ru/C was maintained after five reuse cycles.
- Park, Kwihwan,Jiang, Jing,Yamada, Tsuyoshi,Sajiki, Hironao
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p. 1200 - 1205
(2021/12/29)
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- Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
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The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
- Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 14365 - 14373
(2019/09/06)
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- Catalytic Conversion of Alcohols to Carboxylic Acid Salts and Hydrogen with Alkaline Water
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A [RuH(CO)(py-NP)(PPh3)2]Cl (1) catalyst is found to be effective for catalytic transformation of primary alcohols, including amino alcohols, to the corresponding carboxylic acid salts and two molecules of hydrogen with alkaline water. The reaction proceeds via acceptorless dehydrogenation of alcohol, followed by a fast hydroxide/water attack to the metal-bound aldehyde. A pyridyl-type nitrogen in the ligand architecture seems to accelerate the reaction.
- Sarbajna, Abir,Dutta, Indranil,Daw, Prosenjit,Dinda, Shrabani,Rahaman, S. M. Wahidur,Sarkar, Abheek,Bera, Jitendra K.
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p. 2786 - 2790
(2017/05/31)
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- Efficient phosphine-mediated formal C(sp3)-C(sp3) coupling reactions of alkyl halides in batch and flow
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The construction of C(sp3)-C(sp3) bond is an essential chemical transformation in synthetic chemistry due to its abundance in organic scaffolds. Here we demonstrate a valuable adaptation of the Wittig-type chemical procedure to efficiently facilitate C(sp3)-C(sp3) bond formation utilizing a range of alkyl building blocks. Additionally the method is amenable with flow synthesis to afford coupled products in good to excellent yields without laborious purification process.
- Tran,Hock,Gordon,Koenigs,Nguyen
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supporting information
p. 4950 - 4953
(2017/07/11)
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- Cytotoxic ceramides from the Red Sea sponge Spheciospongia vagabunda
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Extracts of Egyptian marine organisms from the Red Sea were screened for their anticancer activity using sulforhodamine B assay. The extract of the Red Sea sponge Spheciospongia vagabunda possessed promising anticancer activity against HepG2 (liver cancer cell line) and MCF-7 (breast cancer cell line). Isolation of three new ceramides: N-[(2S,3S,4R)-1,3,4-trihydroxytetradecan-2-yl] tridecanamide (1), (R)-2′-hydroxy-N-[(2S,3S,4R)-1,3,4-trihydroxypentacosan-2-yl] octadecanamide (2) and (R,Z)-2′-hydroxy-N-[(2S,3S,4R)-1,3,4-trihydroxytricosan-2-yl) nonadec-10-enamide (3) was accomplished via bioassay-guided fractionation. Structure elucidation was achieved using spectroscopic techniques, including 1D and 2D NMR and HRMS. Compounds 2 and 3 displayed high potential cytotoxicity against HepG2 (IC50 24.7 and 21.3 μM, respectively) and MCF-7 (IC50 26.8 and 29.8 μM, respectively), compared with doxorubicin as control drug.
- Eltamany, Enas Elsayed,Ibrahim, Amany K.,Radwan, Mohamed M.,Elsohly, Mahmoud A.,Hassanean, Hashim A.,Ahmed, Safwat A.
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p. 3467 - 3473
(2015/08/03)
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- METHOD FOR PRODUCING OXYGEN-CONTAINING COMPOUND
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[Problem] There is provided a method for producing an oxygen-containing compound safely and with improved reaction efficiency, in which an undesired peroxide is unlikely to be produced, and efficient heat exchange of the ozonization can be achieved. [Mean for solving the Problem] The method comprises an ozonization reaction step of continuously supplying, together with an organic compound, ozone having an oxygen content of less than 10% in a dissolved state in high-pressure carbon dioxide to an ozonization reaction section having a thin tubular shape, and reacting the ozone and the organic compound under conditions that suppress generation of oxygen due to thermal decomposition of the ozone, thereby continuously producing an ozonide; and a decomposition reaction step of continuously supplying the ozonide produced in the ozonization reaction step to a decomposition reaction section having a thin tubular shape, thereby continuously producing an oxygen-containing compound, the decomposition reaction step being provided in a manner continuous with the ozonization reaction step.
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Page/Page column 22-23
(2012/01/11)
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- Low-concentration ozone reacts with plasmalogen glycerophosphoethanolamine lipids in lung surfactant
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Ozone is a common environmental toxicant to which individuals are exposed to on a daily basis. While biochemical end points such as increased mortality, decrements in pulmonary function, and initiation of inflammatory processes are known, little is actually understood regarding the chemical mechanisms underlying changes in pulmonary health, especially for low concentrations of ozone. This study was undertaken to investigate ozone-induced oxidation of endogenous lipids that are potentially exposed to environmental ozone within lung, specifically focusing on plasmalogen glycerophospholipids present in pulmonary surfactant. Sensitive liquid chromatography - mass spectrometry methods were developed to follow oxidation of diacyl and plasmalogen phosphatidylethanolamine (PE) phospholipids and to identify and quantitate products generated by ozonolysis. Using a unilamellar vesicle system containing a 1:1 molar mixture of 1-O-octadec-1′-enyl-2-octadecenoyl-PE and 1,2-dihexadecanoyl-PC, these studies revealed that the vinyl ether bond of plasmalogens was oxidized preferentially at low concentrations of ozone (100 ppb), when compared to olefinic bond oxidation on ω-9 of the fatty acyl chain in the same phospholipids. Major phospholipid products generated were identified as 1-formyl-2-octadecenoyl-PE and 1-hydroxy-2-octadecenoyl-PE. Heptadecanal and heptadecanoic acid production was also quantitated using gas chromatography - mass spectrometry, and production was consistent with oxidation of the vinyl ether, at low concentrations of ozone. Analysis of murine lung surfactant from C57Bl/6 mice revealed several plasmalogen PE lipid species, encompassing ～38% of total PE species. Upon exposure of ozone (0 and 100 ppb) to murine surfactant, plasmalogen PE molecular species preferentially reacted, as compared to diacyl PE molecular species. Lysophospholipids, pentadecanal, and nonanal were found to be the primary products of surfactant ozone oxidation.
- Wynalda, Kelly M.,Murphy, Robert C.
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body text
p. 108 - 117
(2011/02/26)
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- Oxidation reactions using air as oxidant thanks to silica nanoreactors containing GOx/peroxidases bienzymatic systems
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A new kind of enzymes encapsulation method is presented. It combines the sol-gel method with a templating process using bilayers of phospholipids to provide an organized network of phospholipids inside the silica and in the same time protect the embedded
- Laveille,Phuoc, L. Truong,Drone,Fajula,Renard,Galarneau
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scheme or table
p. 94 - 100
(2011/01/04)
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- Hydrocarboxylation of terminal alkenes in supercritical carbon dioxide
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The catalytic hydrocarboxylation of linear alkenes to carboxylic acids using supercritical carbon dioxide as a solvent was studied. High selectivities in acids have been obtained. The best results were achieved when adding a perfluorinated surfactant to the reaction mixture (93% conversions and ca. 80% selectivity). Comparative multinuclear high-pressure NMR spectroscopic studies in [D8]THF and in supercritical CO2 show the formation of Pd0 species. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Estorach, Clara Tortosa,Orejon, Arantxa,Ruiz, Nuria,Masdeu-Bulto, Anna M.,Laurenczy, Gabor
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experimental part
p. 3524 - 3531
(2009/02/07)
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- Ion-induced specificity change in polymer-catalyzed solvolyses of p-nitrophenyl alkanoates
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Spheres, rods, or vesicles are formed by the polymer 1, depending on the added salt (tris(hydroxymethyl)methylammonium chloride (TrisCl) or NaCl) and its concentration. Consequently, ion-induced substrate specificity occurs in the 1-catalyzed solvolysis o
- Wang,Fife
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p. 1543 - 1545
(2007/10/03)
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- Hair growth composition containing citric acid esters
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Triesters of citric acid are used for inducing, maintaining or increasing hair growth. Compositions for topical application to mammalian hair or scalp comprise an effective amount of from 1% to 99% by weight of an ester of citric acid having the structure (1): where, R1, R2 and R3 each independently represent a branched or unbranched alkyl, alkenyl, aryl, alkylaryl or arylalkyl group, each said group having from 1 to 18 carbon atoms, R4 represents -H, or a branched or unbranched saturated or unsaturated acyl, alkyl, aryl, alkylaryl or aylalkyl group having from 1 to 18 carbon atoms, in the presence of a cosmetically acceptable vehicle for the citric acid ester and in the absence of solid absorbent for the ester;, said effective amount of said ester being sufficient to increase hair growth in the rat, when said composition is applied topically thereto over a period of no more than three months, by at least 10% more than that obtainable using a control composition from which the said ester has been omitted, in accordance with the Rat Hair Growth Test.
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- Release of nicotinamide from fatty acid-nicotinamide equimolar complexes
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The release behavior of nicotinamide (NAA) from fatty acid (FA)-NAA equimolar complexes was examined in a JP XI dissolution test apparatus in JP XI disintegration test medium No. 1 (pH 1.2) at 37°C where the carbon number of FA is 14-18. The time required for 50% or 80% of NAA to release (T50 or T80) was measured, and the effect of the constituent FA on T50 or T80 was investigated. The values of T50 or T80 for FA-NAA formed with odd-numbered FA were larger than those for FA-NAA formed with even-numbered FA whose alkyl chain length is one more carbon number longer, though the values of T50 of T80 increased rather regularly with an increase of the alkyl chain length for only even-numbered or odd-numbered FA. The values of T50 and T80 for FA-NAA formed with heptadecanoic acid (C17-NAA) were about 36 and 102 min, respectively, suggesting that C17-NAA may be applicable to the preparaton of a sustained-release drug formulation.
- Yokoyama,Ueda,Fujie
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p. 3075 - 3076
(2007/10/02)
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- Release kinetics of nicotinamide from fatty acid-nicotinamide equimolar complexes. I. Release characteristics of fatty acid complexes
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The rates of release of nicotinamide (NAA) from fatty acid (FA)-NAA complexes, FA-NAA, were determined in a JP XI dissolution test apparatus in 500 ml of JP XI disintegration test medium No. 1 at 37°C. The release rate constant (k) and the activation Gibbs energy (ΔG+) for the release of NAA from FA-NAA were estimated. The results obtained for FA-NAA were compared with previous results obtained for the thiamine disulfide (TDS) complex, (FA)6-(TDS). The plots of log k against the carbon number of the constituent FA (n) presented a zig-zag line which indicates a downward convex at an odd-numbered position. The plots of ΔG+ against n showed a zig-zag line with an upward convex at an odd-numbered position, though the positive value of ΔG± increased rather regularly with an increase of n for either even-numbered or odd-numbered FA. The phenomena that the plots of log k vs. n and ΔG+ vs. n show zig-zag lines due to the difference between even- and odd-numbered FA were the same as observed previously for the release of TDS from (FA)6 (TDS).
- Yokoyama,Ueda,Fujie
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p. 2696 - 2698
(2007/10/02)
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- Synthesis of 3-Alkylcatechols via Intramolecular Cyclization
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The intramolecular cyclization of 2-alkanoyl-2,5-dimethoxytetrahydrofurans 4 with aqueous acid is described. 3-Alkylcatechols 7 were prepared in generally good yields by boiling the dioxane solution of compounds 4 in the presence of 1 M hydrochloric acid.In addition, 4,5-dioxoalkanals 6 were obtained in good to high yields when the dioxane solution of compounds 4 was treated with 0.1 M hydrochloric acid.
- Miyakoshi, Tetsuo,Togashi, Hiroyasu
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p. 407 - 410
(2007/10/02)
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- RHODIUM CATALYZED REDUCTIVE ESTERIFICATION REACTIONS
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Reductive esterification occurs when unsaturated acids are treated with hydrogen in alcohol using either rhodium trichloride or the dimer of chloro(1,5-hexadiene)rhodium(I) as the catalyst.Saturated acids containing appropriate functional groups are also esterified under the same conditions.
- Lin, Ivan J. B.,Zahalka, Hayder A.,Alper, Howard
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p. 1759 - 1762
(2007/10/02)
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- α,α-DICHLOROALDEHYDES AND α,α-DICHLOROCARBOXYLIC ACIDS FROM LONG CHAIN 1-ALKANOLS. IMPROVED CHLORINATION IN THE SYSTEM DMF-CHCl3-MgCl2
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Production of α,α-dichloroaldehydes by direct chlorination of 1-alkanols with chlorine gas, catalyzed by DMF and DMF*HCl, was extended to long chain compounds (CnH2n+1OH; n = 5, 6, 8, 10, 12, 14, 16, 18).Two problems specific to the longer chains were solved to obtain isolated yields in the range 70-85 percent; a) parasitic radical chlorination was largely controlled by shielding from light; b) alkyl alkanoate side product (8 percent for n = 8 but 25 percent for n = 16 or 18) was decreased to 0-2 percent in the presence of MgCl2*H2O.Homogeneity of the reaction medium was improved with chloroform as a cosolvent.Oxidation of the aldehydes to dichlorocarboxylic acids proceeded smoothly with aqueous KMnO4 up to the tetradecanal.For the longer chains 30 percent hydrogen peroxide-NaHCO3 in acetone (overnight at 48-52 deg C) was the preferred oxidant.
- Buyck, L. De,Casaert, F.,Lepeleire, C. De,Schamp, N.
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p. 525 - 534
(2007/10/02)
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- Photochemistry of reactive surface-active compounds in adsorbed monolayers
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The reactions of long-chain diazo ketones and azides in adsorbed monolayers on inorganic solids were investigated and compared with the corresponding behaviour in monolayers at the air-water interface. The isolated products indicate that reaction of photochemically generated intermediates occurs both with co-adsorbed water and with hydroxyl groups on the solid surface. In the case of 1-diazo-2-oxoheptadecane, for example, the products of these two reactions are heptadecanoic acid and a surface-grafted long-chain ester. The latter can be removed as methyl heptadecanoate by ester exchange using methanolic HCl. Pronounced differences were observed between alumina, silica gel and fumed silica as supports, and were attributed to differences in the amount of adsorbed H2O and in the density of surface hydroxyl groups.
- Holden, David A.,Taylor, Joseph W.,Clausen, Diane
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p. 1671 - 1678
(2007/10/02)
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- THE INVENTION OF NEW RADICAL CHAIN REACTIONS. PART X. HIGH YIELD RADICAL ADDITION REACTIONS OF αβ-UNSATURATED NITROOLEFINS. AN EXPEDIENT CONSTRUCTION OF THE 25-HYDROXY-VITAMIN D3 SIDE CHAIN FROM BILE ACIDS.
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Radicals derived from thiohydroxamic esters 3 readily add to nitroolefins 5 (Z=NO2) to give good yields of α-nitrosulphides.These adducts, where the structure permits, are easily oxidised to carboxylic acids 8 by treatment with alkaline hydrogen peroxide.Reductive cleavage to the corresponding aldehydes or ketones 9 is efficiently carried out by the action of TiCl3.Addition of methyl magnesium iodide to methyl ketone derived from 3α-acetoxy 11-oxo cholanic acid gives steroid 10 possessing the 25-hydroxycholesterol side chain of the vitamin D3 metabolites.Radical additions to 1-phenylthio-2-nitropropene 11 have been briefly studied.
- Barton, Derek H.R.,Togo, Hideo,Zard, Samir Z.
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p. 5507 - 5516
(2007/10/02)
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