97-62-1Relevant academic research and scientific papers
A methodical selection process for the development of ketones and esters as bio-based replacements for traditional hydrocarbon solvents
Byrne, Fergal P.,Forier, Bart,Bossaert, Greet,Hoebers, Charly,Farmer, Thomas J.,Hunt, Andrew J.
supporting information, p. 4003 - 4011 (2018/09/11)
A "top down" approach to the development of sustainable, greener, low-polarity solvents is presented. Methyl butyrate, ethyl isobutyrate, methyl pivalate and pinacolone were identified as potential target solvents from trends in Hansen solubility parameters and known physical properties. Solubility, flammability and physical properties were determined which showed their potential to replace traditional, hazardous, volatile, non-polar solvents such as toluene. Each new candidate then demonstrated their suitability to replace these traditional solvents in solubility tests, despite being esters and ketones, each candidate demonstrated their similarity to traditional volatile non-polar solvents in terms of their solubility properties by their ability to dissolve natural rubber, a particularly low-polarity solute. This was reinforced by their performance in a model Menschutkin reaction and a radical-initiated polymerisation for the production of pressure-sensitive adhesives, where their performance was found to be similar to that of toluene. Importantly, a preliminary toxicity test (Ames test) suggested non-mutagenicity in all candidates. Each of the four candidates can be synthesised via a catalytic route from potentially renewable resources, thus enhancing their green credentials.
Hydrogenation of Ketones and Esters Catalyzed by Pd/C?SiO2
Akchurin,Baibulatov,Dokichev
, p. 195 - 198 (2018/03/26)
Hydrogenation of unsaturated ketones and esters with molecular hydrogen on the 5%Pd/C?SiO2 heterogeneous catalyst has been studied. The reaction direction and yield are determined by the starting compounds structure. Hydrogenation of unsaturated ketones containing phenyl group at the double carbon–carbon atom is accompanied by the reduction of the ketone group into the alcohol one. Hydrogenation of unsaturated esters is accompanied by transesterification.
NANOEMULSIONS
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Page/Page column 20, (2016/09/22)
An oil-in-water emulsion comprises an emulsifier which is a non-gelled branched polymer (e.g. a branched vinyl polymer), wherein the ends of at least some of the chains of said polymer terminate in an alkyl chain of 5 carbon atoms or more, and wherein the oil-in-water emulsion takes the form of particles having a z-average diameter of no greater than about 1000 nm. This is useful in, for example, facilitating the carrying of hydrophobic materials within aqueous systems, to enhance oral drug delivery. The oil-in-water emulsion may be prepared by mixing an oil phase with an aqueous phase in the presence of an emulsifier, wherein said emulsifier is a non-gelled branched polymer, wherein the ends of at least some of the chains of said polymer terminate in an alkyl chain of 5 carbon atoms or more, and wherein the oil-in-water emulsion takes the form of particles having a z-average diameter of no greater than about 1000 nm. The oil phase may comprise a further solvent which is miscible with the oil, said solvent being allowed to evaporate to produce the final emulsion.
Synthesis of Multivalent Organotellurium Chain-Transfer Agents by Post-modification and Their Applications in Living Radical Polymerization
Fan, Weijia,Nakamura, Yasuyuki,Yamago, Shigeru
supporting information, p. 17006 - 17010 (2016/11/16)
Functionalized or multivalent organotellurium chain-transfer agents (CTAs) for living radical polymerization were synthesized by post-modification, which involved the condensation between a carboxylic-acid-functionalized CTA and various amines in excellent yields without affecting the reactive tellurium moiety. The CTAs exhibited high synthetic versatility for radical polymerization and gave structurally well-controlled polymers, such as multiarmed polymers, from various monomers. Because all new CTAs are easily available on a large scale by simple purification, the current method significantly facilitates macromolecular engineering based on organotellurium-mediated radical polymerization (TERP).
Mixed-ligand complexes of paddlewheel dinuclear molybdenum as hydrodehalogenation catalysts for polyhaloalkanes
Tsurugi, Hayato,Hayakawa, Akio,Kando, Shun,Sugino, Yoshitaka,Mashima, Kazushi
, p. 3434 - 3439 (2015/05/27)
We developed a hydrodehalogenation reaction of polyhaloalkanes catalyzed by paddlewheel dimolybdenum complexes in combination with 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene (MBTCD) as a non-toxic H-atom source as well as a salt-free reductant. A mixed-ligated dimolybdenum complex Mo2(OAc)2[CH(NAr)2]2 (3a, Ar = 4-MeOC6H4) having two acetates and two amidinates exhibited high catalytic activity in the presence of nBu4NCl, in which [nBu4N]2[Mo2{CH(NAr)2}2Cl4] (9a), derived by treating 3a with ClSiMe3 and nBu4NCl, was generated as a catalytically-active species in the hydrodehalogenation. All reaction processes, oxidation and reduction of the dimolybdenum complex, were clarified by control experiments, and the oxidized product, [nBu4N][Mo2{CH(NAr)2}2Cl4] (10a), was characterized by EPR and X-ray diffraction studies. Kinetic analysis of the hydrodehalogenation reaction as well as a deuterium-labelling experiment using MBTCD-d8 suggested that the H-abstraction was the rate-determining step for the catalytic reaction. This journal is
Why are organotin hydride reductions of organic halides so frequently retarded? kinetic studies, analyses, and a few remedies
Ingold,Bowry, Vincent W.
, p. 1321 - 1331 (2015/02/19)
Kinetic data for reduction of organic halides (RX) by tri-n-butylstannane (SnH) reveal a serious flaw in the current view of the kinetic radical chain: the tacit but unproven assumption that the speed of reaction is determined by the slowest propagation step. Our results show this is rarely true for reductive chains and that the observed rate is in fact controlled by unseen side-reactions of propagating R? and Sn? radicals with the solvent (notably, benzene!) or solvent impurities (e.g., trace benzophenone dryness indicator in THF) or, crucially, with allylic-CH and conjugated unsaturated groups in substrates and products. Most R? and/or Sn? radicals are therefore converted into relatively inert delocalized species A? and/or B? that inhibit the chain. Retardation in the degraded chain is given by a simple sum of terms, each being the ratio of the chain-transfer rate divided by the rate of chain-return. The model kinetic equation is linear and easy to ratify, interpret, and apply: to calculate retarding rate constants, optimize reaction conditions, and identify additives or "remedies" that repair the chain and accelerate reaction. The present work is thus expected to have a helpful impact on the practice and design of SnH radical chain based (and related) syntheses.
Scope and mechanism of the electrochemical Reformatsky reaction of α-haloesters on a graphite powder cathode in aqueous anolyte
De Souza, Carlos A.,Navarro, Marcelo,Bieber, Lothar W.,Areias, Madalena C.C.
, p. 118 - 126 (2014/05/06)
Six α-haloesters and eighteen carbonyl compounds were submitted to electrochemical coupling on a graphite powder cathode using aqueous anolyte free of organic solvents. Preparative yields of coupling products could be obtained with ethyl 2-bromoisobutyrate and aromatic aldehydes. Ethyl 2-bromopropionate was much less efficient. Extensive variation of applied potential, electrolyte composition, stoichiometry, catalyst, leaving halogen and activating substituents on the carbonyl compound led to the conclusion that the reaction mechanism in most cases proceeds via a radical intermediate generated from the halide reduction. Ethyl chloroacetate produced only trace amounts of coupling product, most probably by a carbanionic mechanism.
Expanding ester biosynthesis in Escherichia coli
Rodriguez, Gabriel M,Tashiro, Yohei,Atsumi, Shota
, p. 259 - 265 (2014/04/03)
To expand the capabilities of whole-cell biocatalysis, we have engineered Escherichia coli to produce various esters. The alcohol O-acyltransferase (ATF) class of enzyme uses acyl-CoA units for ester formation. The release of free CoA upon esterification with an alcohol provides the free energy to facilitate ester formation. The diversity of CoA molecules found in nature in combination with various alcohol biosynthetic pathways allows for the biosynthesis of a multitude of esters. Small to medium volatile esters have extensive applications in the flavor, fragrance, cosmetic, solvent, paint and coating industries. The present work enables the production of these compounds by designing several ester pathways in E. coli. The engineered pathways generated acetate esters of ethyl, propyl, isobutyl, 2-methyl-1-butyl, 3-methyl-1-butyl and 2-phenylethyl alcohols. In particular, we achieved high-level production of isobutyl acetate from glucose (17.2 g l -1). This strategy was expanded to realize pathways for tetradecyl acetate and several isobutyrate esters.
Arylazolylthioacetanilide. Part 11: Design, synthesis and biological evaluation of 1,2,4-triazole thioacetanilide derivatives as novel non-nucleoside HIV-1 reverse transcriptase inhibitors
Li, Zhenyu,Cao, Yuan,Zhan, Peng,Pannecouque, Christophe,Balzarini, Jan,De Clercq, Erik,Shen, Yuemao,Liu, Xinyong
, p. 968 - 973 (2014/01/06)
A series of novel 1,2,4-triazole thioacetanilide derivatives has been designed, synthesized and evaluated for their anti-HIV activities in MT-4 cells. Half of these compounds showed moderate to potent activities against wild-type HIV-1 with an EC50 ranging from 38.0 μM to 4.08 μM. Among them, 2-(4-(2-fluorobenzyl)-5-isopropyl-4H-1,2,4-triazol-3-ylthio)-N-(2-nitrophenyl) acetamide 7d was identified as the most promising compound (EC50 = 4.26 μM, SI = 49). However, no compound was active against HIV-2. The preliminary structure-activity relationships among the newly synthesized congeners are discussed.
