- Synthesis of Succinic Gemini Surfactants and the Effect of Stereochemistry on Their Monolayer Behaviors
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In this work, succinic gemini surfactants, dl- and meso-2,3-bis(alkyl)succinic acids (alkyl: C6H13-C13H27), were successfully synthesized by oxidative coupling of enolates of fatty acid tert-butyl esters with copper(II) bromide followed by treatment with CF3COOH. Focusing on the influence of stereochemistry (dl- and meso-) of succinic geminis, their monolayer behaviors at the air-water interface were explored using surface pressure-area (Π-A) isotherms, the compression modulus of monolayers (εs), and Brewster angle microscope (BAM) analysis. meso-2,3-Bis(undecyl)succinic acid showed a unique isotherm where the surface pressure drastically decreased at A = ～0.56 nm2 (Π = 21.9 mN m-1) regardless of compression rates and subphase temperatures, while dl-isomer showed the common isotherm of gas → liquid-expanded → liquid-condensed phase transitions. BAM analysis on meso-2,3-bis(undecyl)succinic acid films at the air-water interface showed that small islands of aggregates appear just after the maximum pressure (A = ～0.56 nm2), and on further compression needle-shaped assemblies appear that can grow in size. It was reasonably concluded that hydrophobic interactions can operate more effectively in meso-isomers than in dl-isomers, and that meso-molecules can "jump up" to cause a transition from monolayer to bilayer. This is the first finding of the "jumping-up" phenomenon of gemini surfactants having meso-stereochemistry.
- Kawase, Tokuzo,Kagawa-Ohara, Maiko,Aisaka, Tsunetomo,Oida, Tatsuo
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- Potential Vegetable-Based Diesel Fuels from Perkin Condensation of Furfuraldehyde and Fatty Acid Anhydrides
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Domestically produced biofuels may help to reduce dependence on imported oil for powering transportation and infrastructure in the future. In this report, we reacted medium-chain and long-chain fatty anhydrides (capric, caprylic, lauric, and palmitic) with furfuraldehyde by the Perkin condensation to produce 2-n-alkenylfurans. In the second step, the 2-n-alkenylfurans were hydrogenated to form 2-n-alkyltetrahydrofurans. Basic fuel property testing (melting point, density, kinematic viscosity, derived cetane number, and calorific value) of the 2-n-alkyltetrahydrofurans indicates they are potentially useful as fuels for diesel engines. The mixture composed of 2-octyl- and 2-decyltetrahydrofuran had the best combination of fuel properties including a low melting point (?39 °C), high cetane number (63.1), high flash point (98.2 °C), and low viscosity (2.26 mm2 s?1, 40 °C), which compares favorably with specifications for diesel #2 and biodiesel.
- Baldwin, Lawrence C.,Davis, Matthew C.,Hughes, Alicia M.,Lupton, David V.
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p. 571 - 583
(2019/04/08)
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- Nickel catalyzed decarboxylative alkylation of aryl triflates with anhydrides
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Aliphatic acid anhydrides are the versatile building blocks and the new method for the conversion of anhydrides is thus of great significance. Herein, we report the decarboxylative alkylation of aryl triflates with aliphatic acid anhydrides via nickel catalysis. This novel method provides a facile access to construct Csp2-Csp3 bond. In addition, this method is compatible with a broad array of functional groups and exhibits good substrates scope.
- Chen, Hui,Liao, Xuebin
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p. 4186 - 4191
(2019/06/18)
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- Use of glycerol carbonate in an efficient, one-pot and solvent free synthesis of 1,3-sn-diglycerides
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An efficient solvent-free synthesis of a variety of highly pure 1,3-sn-diglycerides (1,3-sn-diacylglycerols) in a two-step one pot process is described. Heating glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one) with fatty acid anhydrides 2a-d affords 1:1 mixtures of glycerol carbonate fatty esters 3a-3d and the corresponding fatty acids. Further heating the reaction mixtures in the presence of catalytic amounts of 1,4-diazabicyclo[2.2.2]octane (DABCO) at 195-200 °C yields highly pure 1,3-sn-diglycerides 4a-4d.
- Kargar, Mojgan,Hekmatshoar, Rahim,Ghandi, Mehdi,Mostashari, Abdoljalil
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p. 259 - 264
(2013/07/27)
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- Synthesis of symmetric anhydrides using visible light-mediated photoredox catalysis
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A new approach to anhydride formation is reported via activation of C-O bonds by the Vilsmeier-Haack reagent formed by Ru(bpy)3Cl2 and CBr4 in DMF. Various aryl and alkyl carboxylic acids are converted to the corresponding anhydrides in excellent yields.
- Konieczynska, Marlena D.,Dai, Chunhui,Stephenson, Corey R. J.
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supporting information; experimental part
p. 4509 - 4511
(2012/07/31)
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- Synthesis and characterization of long chain alkyl acyl carnitine esters. Potentially biodegradable cationic lipids for use in gene delivery
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A series of alkyl acyl carnitine esters (alkyl 3-acyloxy-4- trimethylammonium butyrate chloride) were synthesized as potential biocompatible cationic lipids for use in gene transfer. The physicochemical properties of the lipids, liposomes prepared from them, and their complexes with DNA were characterized by differential scanning calorimetry (DSC), particle size, potential, and surface monolayer measurements. The transition temperatures and behavior at an air-water interface for this series are similar to phosphatidylcholines with the same hydrocarbon chain length. The physical properties of the L derivatives were not significantly different from the DL derivatives. At 70 °C, the acyl chains were readily hydrolyzed at pH 7. The influence of the aliphatic chain length (n = 12-18) on transfection efficiency in vitro was determined using cationic liposomes prepared from these lipids or their mixtures with the helper lipids, dioleoylphosphatidylethanolamine (DOPE), dioleoylphosphatidylcholine, monooleoylglycerol, and cholesterol (Chol). The mixture of myristyl 3- myristoyloxy-4-trimethylammonium butyrate chloride (MMCE, 4d) with DOPE at a 1:1 molar ratio mediated the highest transfection efficiency in cell culture. The mixture of oleyl 3-oleoyloxy-4-trimethylammonium butyrate chloride (OOCE, 4f) with Chol at a 1:1 molar ratio gave the highest transfection efficiency after intravenous administration in mice. In vivo gene expression using 4f was comparable to values obtained with the best cationic lipids reported to date.
- Wang, Jinkang,Guo, Xin,Xu, Yuhong,Barron, Lee,Szoka Jr., Francis C.
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p. 2207 - 2215
(2007/10/03)
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- A search for quantitative acylation of α-trinositol (1D-myo-inositol 1,2,6-tris(dihydrogen phosphate) pentasodium salt)
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The acylation of α-trinositol is very sensitive to reaction conditions. Competing condensation reactions may give pyrophosphates and cyclic phosphates. Treatment of a tert-ammonium salt corresponding to α-trinositol with carboxylic acid anhydride and DMAP gives a good yield of the expected esters.
- Malmberg, Mats,Rehnberg, Nicola
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p. 459 - 464
(2007/10/03)
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- N-docosahexaenoyl, 3 hydroxytyramine: A dopaminergic compound that penetrates the blood-brain barrier and suppresses appetite
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Fatty acids with varying chain lengths (2-22 carbon atoms long) and degrees of unsaturation (0-6 double bonds) were used to synthesize dopaminergic compounds for a study of the carrier mediated transport of dopamine (DA) to the brain. The most active carrier was the all cis C22:6 fatty acid [docosahexaenoic acid,( DHA)]which increased DA uptake through the blood-brain barrier by greater than 7.5 fold. The DHA-DA compound, NMI 8739, depressed the general locomotor activity of mice in a dose dependent manner. It also suppressed the appetite of Balb c mice and Charles River rats by 50% and 95% respectively at a dose of 10 mg/kg. Daily administration of NMI-8739 for a three week period did not induce tolerance. These results demonstrate DHA's potential for the carrier mediated transport of small molecules to the brain.
- Shashoua, Victor E.,Hesse, Gary W.
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p. 1347 - 1357
(2007/10/03)
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- REACTION OF PHOSPHORUS TRICHLORIDE WITH CARBOXYLIC ACIDS
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The reaction of phosphorus trichloride with a number of monobasic carboxylic acids has been studied and the optimum ratio of reactants for the yield of acid chlorides has been established.Based on analysis and the data from 31P NMR spectroscopy of the phosphorus-containing products from this reaction it is shown that at 40-50 deg C a mixture of P-H acids having a predominant content of pyrophosphorous acid is formed.
- Valitova, L. A.,Popova, E. V.,Ibragimov, Sh. N.,Ivanov, B. E.
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p. 366 - 370
(2007/10/02)
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- Azomethine dye derived from a compound having a pyrazolo triazole moiety
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An azomethine dye is derived from a pyrazolo triazolo coupler compound of general formula (I) and/or a polymer coupler having a repeating unit derived from a vinyl monomer containing in its molecule a moiety of general formula (I): where R1 and R2 are each H, halogen or a substituent; X is H, a halogen or a coupling releasable group; or R1, R2 or X may each be a simple bond or a linking group for forming a bis-coupler; or R1 or R2 may be a simple bond or a linking group through which the moiety of general formula (I) is bonded to the vinyl group of a vinyl monomer. 72 specific couplers are shown, and six synthesis methods. Color development produces good magenta image free from subsidiary yellow absorptions.
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- Pyrazolo(1,5-B)-1,2,4-triazole derivatives
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A novel pyrazolo[1,5-b]-1,2,4-triazole derivative represented by the general formula (I) is described. STR1 wherein R1 and R2 which may be the same or different, each represents a hydrogen atom or a substituent; X represents a hydrogen atom or a group capable of being released upon coupling; and Y represents a hydrogen atom or an aralkyl group.
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- PHASE MANAGED ORGANIC SYNTHESIS 2. A NEW POLYMER ASSISTED SYNTHESIS OF ACID ANHYDRIDES.
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A solid-phase copolymer of 4-vinylpyridine is shown to be a highly effective reagent/catalyst for the synthesis of acid anhydrides from mixtures containing equimolar quantities of carboxylic acid and acid chlorides.The process may be carried out in batch or column mode.
- Fife, Wilmer K.,Zhang, Zhi-dong
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p. 4933 - 4936
(2007/10/02)
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- Synthesis and Tautomeric Structures of Acyl-Cyclopentane-1,2,4-triones
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A series of acyl-cyclopentane-1,2,4-triones containing alkyl substituents of different length have been prepared by acylating 3-substituted cyclopentane-1,2,4-triones, using gaseous BF3 as catalyst.The 1H and 13C n.m.r. spectra of these compounds have been analysed in order to gain information about the tautomeric forms favoured by the acyl-cyclopentanetriones.
- Franklin, Roger W.,Ward, Robert S.,Roberts, David W.
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p. 3246 - 3260
(2007/10/02)
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