- "click" tetradentate ligands
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A series of triazole-based N4 tetradenate ligands 1a-d are efficiently synthesized using CuI-catalyzed azide-alkyne "click" strategy and are readily coordinated to many metal ions (e.g. MnII, NiII, ZnII and FeII). The X-ray structures of the resultant metal-complexes (4a-d, 5a, 6a and 7a) reveal an octahedral mononuclear structure with two co-ligands bonded in cis sites and the two triazoles as nitrogen donors to the metal center. The MnII-complexes (4a-d) show efficient catalytic activities in the epoxidation of various aliphatic terminal olefins with peracetic acid, and feature with low catalyst loading, fast conversion and high yields. The Royal Society of Chemistry 2010.
- Hao, Erhong,Wang, Zhaoyun,Jiao, Lijuan,Wang, Shaowu
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Read Online
- Efficient Synthesis of Cyclic Carbonates from Unsaturated Acids and Carbon Dioxide and their Application in the Synthesis of Biobased Polyurethanes
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Bio-derived furan- and diacid-derived cyclic carbonates have been synthesized in high yields from terminal epoxides and CO2. Furthermore, four highly substituted terpene-derived cyclic carbonates were isolated in good yields with excellent diastereoselectivity in some cases. Eleven new cyclic carbonates derived from 10-undecenoic acid under mild reaction conditions were prepared, providing the corresponding carbonate products in excellent yields. The catalyst system also performed the conversion of an epoxidized fatty acid n-pentyl ester into a cyclic carbonate under relatively mild reaction conditions (80 °C, 20 bar, 24 h). This bis(cyclic carbonate) was obtained in high yields and with different cis/trans ratios depending on the co-catalyst used. An allyl alcohol by-product was only observed as a minor product when bis(triphenylphosphine)iminium chloride was used as co-catalyst. Finally, two cyclic carbonates were used as building blocks for the preparation of non-isocyanate poly(hydroxy)urethanes by reaction with 1,4-diaminobutane.
- Martínez, Javier,de la Cruz-Martínez, Felipe,Martínez de Sarasa Buchaca, Marc,Fernández-Baeza, Juan,Sánchez-Barba, Luis F.,North, Michael,Castro-Osma, José A.,Lara-Sánchez, Agustín
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p. 460 - 468
(2021/04/06)
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- Hyperbranched polyesters by polycondensation of fatty acid-based AB: N-type monomers
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Widely available vegetable oils were readily derivatized into chemically pure ABn-type monomers (n = 2 or 3). Their polymerization led to unprecedented hyperbranched polyesters. Four different AB2/AB3-type monomers bearing one A-type methyl ester and two or three B-type alcohol functions were purposely synthesized via two elementary steps, i.e. epoxidation of the internal double bond of the vegetable oil precursors followed by ring-opening of the epoxy groups under acidic conditions. The polycondensation of these bio-sourced monomers was performed in bulk, in the presence of an appropriate catalyst, giving access to modular hyperbranched polyesters with tunable properties. Among the catalysts tested, zinc acetate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and sodium methoxide proved the most effective, allowing the achievement of molar masses in the range 3000-10000 g mol-1 and dispersities varying from 2 to 15, depending on the initial conditions. The degree of branching, DB, as determined by 1H NMR spectroscopy, was found to be between 0.07 and 0.45. The as-devised hyperbranched polyesters displayed either amorphous or semi-crystalline properties, as a function of the selected AB2/AB3-type initial monomers, with a glass transition temperature, Tg, ranging from -33 to 9 °C and a decomposition temperature at 5 wt% of the sample, Td5%, varying from 204 to 340 °C.
- Testud, Blandine,Pintori, Didier,Grau, Etienne,Taton, Daniel,Cramail, Henri
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p. 259 - 269
(2017/08/16)
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- Total Synthesis of Four Isomers of the Proposed Structures of Cryptorigidifoliol K
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The first asymmetric convergent total synthesis of four isomers of proposed structures of cryptorigidifoliol K (1a, 1b, 1c, and 1d) has been achieved from commercially available starting materials. The key steps in this synthesis involve tandem isomerization followed by a C-O and C-C bond-forming reaction for the construction of trans-2,6-disubstituted dihydropyran, iodolactonization, isomerization of terminal alkene, and cross-metathesis reaction. The large discrepancies in the spectroscopic data (1H NMR) of synthetic cryptorigidifoliol K from the natural product suggest that the structure of the natural cryptorigidifoliol K requires revision.
- Reddy, G. Sudhakar,Padhi, Birakishore,Bharath, Yada,Mohapatra, Debendra K.
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supporting information
p. 6506 - 6509
(2017/12/26)
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- Synthesis of fully alternating polycarbonate with low Tg from carbon dioxide and bio-based fatty acid
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The selective copolymerization of CO2 and an epoxide to form fully alternating polycarbonates is a great challenge via catalysis with the zinc-cobalt(iii) double metal cyanide complex [Zn-Co(iii) DMCC]. We describe the first perfectly alternating copolymerization of CO2 with a bio-based epoxide. The resultant polycarbonate had a low Tgs of -38 to -44 °C and two end hydroxyl groups, which were then used to initiate ring-opening polymerization of l-lactide via metal-free catalysis, affording a biodegradable triblock copolymer. This study provides a new platform copolymer for making various advanced polymers with biodegradable properties. This journal is the Partner Organisations 2014.
- Zhang, Ying-Ying,Zhang, Xing-Hong,Wei, Ren-Jian,Du, Bin-Yang,Fan, Zhi-Qiang,Qi, Guo-Rong
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p. 36183 - 36188
(2014/11/07)
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- An enzymatic approach to bifunctional chelating agents
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Bifunctional chelating agents (BFCAs) combine the complexing properties of a multidentate ligand with the presence of a free reactive functional group, mainly devoted to conjugation purposes. Indeed, products obtained by conjugation of a BFCA to a biomolecule and coordination of a suitable metal ion are widely applied in medicine nowadays as diagnostic and therapeutic agents. BFCAs are generally prepared through multi-step syntheses and with extensive application of protection-deprotection strategies, due to the large number of functional groups involved. Hydrolytic enzymes, with their unique chemoselectivity, provided the best results in the preparation of three different BFCAs based on very useful and well known ligand platforms. This journal is the Partner Organisations 2014.
- Minazzi, Paolo,Lattuada, Luciano,Menegotto, Ivan G.,Giovenzana, Giovanni B.
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p. 6915 - 6921
(2014/10/15)
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- New cytotoxic annonaceous acetogenin mimetics having a nitrogen- heterocyclic terminal and their application to cell imaging
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A terminal unsaturated lactone or its equivalent is commonly believed to be essential for the cytotoxicity of natural annonaceous acetogenins and their artificial mimetics. In this work, we discovered a series of new cytotoxic ethylene glycol ether-contai
- Chen, Yi-Jie,Jin, Sheng,Xi, Jie,Yao, Zhu-Jun
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supporting information
p. 4921 - 4928
(2014/07/07)
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- Epoxidation of alkenes bearing a carboxylic acid group by iron complexes of the tetradentate ligand N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)-1, 2-diaminoethane and its derivatives
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The addition of carboxylic acids enhances the rate and selectivity of alkene oxidations catalyzed by [(bpmen)Fe(OTf)2] (bpmen = N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)-1,2-diaminoethane). The syntheses and characterizations of four derivatives of this iron complex with varying substitutions on the pyridine ring and with a substituted piperazine backbone are reported. These [(L)Fe(OTf)2] complexes and [(bpmen)Fe(OTf)2] are employed as catalysts for the oxidation of alkenes bearing a carboxylic acid functional group, namely oleic acid, undecylenic acid, 5-hexenoic acid and 4-pentenoic acid, with hydrogen peroxide as the oxidant. Comparisons with the analogous ester substrates demonstrate the beneficial impact of the acid functional group on conversion and selectivity when using [(bpmen)Fe(OTf)2] as a catalyst. For the oleic and undecylenic acids, epoxide product is formed with moderate to high conversions and high selectivities. Under the conditions employed, 4-pentenoic acid is oxidized to a γ-lactone, most likely via the epoxide intermediate, and 5-hexenoic acid to a mixture of epoxide and δ-lactone. Of the iron complexes with bpmen derivatives as ligands, only the N,N′-dimethyl-N, N′-bis(5-chloropyridin-2-ylmethyl)-1,2-diaminoethane variant shows appreciable activity. The effect of solvent choice is also investigated.
- Morris, Lilliana S.,Girouard, Michael P.,Everhart, Matthew H.,McClain, William E.,Van Paridon, John A.,Pike, Robert D.,Goh, Christopher
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p. 149 - 159
(2014/03/21)
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- Synthesis, characterization, and evaluation of 10-undecenoic acid-based epithio derivatives as multifunctional additives
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Novel epithio compounds from alkyl epoxy undecanoates (n-alkyl, C1, C4, and C6; isoalkyl, C3, C4, and C8) were synthesized using an ammonium thiocyanate in ionic liquid 1-methylimidazolium tetrafluoroborate/H2O (2:1) solvent system in 85-90% yields by gas chromatographic (GC) analysis. The synthesized products were characterized by 1H and 13C nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy (FTIR), gas chromatography, and GC mass spectral (GC-MS) analyses and evaluated for their antioxidant, extreme pressure (EP), and antiwear (AW) properties in three different base oils, namely, epoxy jatropha fatty acid n-butyl esters (EJB), di-2-ethylhexyl sebacate (DOS), and mineral oil (S-105). Among the synthesized products, n-butyl epithio undecanoate exhibited superior antioxidant property (229.2 °C) compared to butylated hydroxytoluene (BHT, 193.8 °C) in base oil DOS and comparable performance in EJB and S-105 base oils. All of the epithio derivatives exhibited significantly enhanced weld point for the base oils EJB and DOS at 2 wt % level and displayed moderate enhancement in S-105 base oil. Methyl epithio undecanoate at 0.6% concentration exhibited considerable improvement in the wear scar of DOS base oil. The synthesized epithio derivatives have potential as multifunctional additives in lubricant formulations.
- Geethanjali, Gorla,Padmaja, Korlipara V.,Sammaiah, Arukali,Prasad, Rachapudi B. N.
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p. 11505 - 11511
(2015/02/19)
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- Envirocat (K10-MX)-catalyzed regioselective transformation of alkenes into iodohydrins and β-iodo ethers and further conversion of iodohydrins to epoxides using Al2O3-Na2Co3 under MWI
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Commercial K10 clay was converted to extremely efficient and environmentally friendly catalyst K10-MX for the preparation of iodohydrins and β-iodo ethers from alkenes (terminal as well as internal) using microwave irradiation. This method was further extended for the conversion of alkenes to epoxides via iodohydrin intermediate in a one-pot reaction system. Copyright Taylor & Francis Group, LLC.
- Shallu,Sharma,Singh, Jasvinder
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p. 1306 - 1324
(2012/04/04)
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- New methodology for the conversion of epoxides to alkenes
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Epoxides have been transformed in good yields to alkenes by a process involving (i) ring-opening of the epoxide with 2-mercaptobenzothiazole, (ii) oxidation of the derived ss-hydroxy thioethers to the corresponding sulfones, and (iii) thermal or base-promoted fragmentation of these sulfones to alkenes. The stereochemistry of the starting epoxide is transfer-red faithfully to the alkene product, because of the SN2 epoxide ring-opening reactions and the antiperiplanar SO2 elimination reaction of the ss- alkoxysulfinate intermediates. This methodology may form the basis of a new protecting group strategy for alkenes.
- Wu, Feng-Ling,Ross, Benjamin P.,McGeary, Ross P.
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experimental part
p. 1989 - 1998
(2010/06/15)
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- Structure-activity relationship study of flowering-inducer FN against Lemna paucicostata
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FN1 (1) and FN2 (2), cycloadducts of α-ketol octadecadienoic acid (3) with norepinephrine (NE), induce flowering in Lemna paucicostata. In order to broaden our understanding of structural requirements of FN?for flower induction, nine analogs of 3 (4-12) were synthesized and reacted with NE under basic conditions. These analogs, except for 8, 10, and 12, exhibited significant activity regarding to floral induction in L. paucicostata. Similar experiments were carried out by using 3 and epinephrine, and it was demonstrated that these products also possessed biological activity.
- Kai, Kenji,Takeuchi, Jun,Kataoka, Taichi,Yokoyama, Mineyuki,Watanabe, Naoharu
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p. 6760 - 6769
(2008/12/21)
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- Catalytic enantioselective thioester aldol reactions that are compatible with protic functional groups
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This communication reports highly enantioselective and diastereoselective methyl malonic acid half thioester (MeMAHT) aldol reactions that are compatible with protic functional groups and enolizable aldehydes, affording syn S-phenyl thiopropionates. Copyright
- Magdziak, Derek,Lalic, Gojko,Lee, Hong Myung,Fortner, Kevin C.,Aloise, Allen D.,Shair, Matthew D.
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p. 7284 - 7285
(2007/10/03)
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- Design of a highly efficient catalyst for the oxaziridinium-mediated epoxidation of olefins by Oxone
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2,3,3-Trimethyl-7-nitro-3,4-dihydroisoquinolinium tetrafluoroborate is a highly efficient catalyst for the oxaziridinium-mediated epoxidation of a variety of olefins, including monosubstituted ones.
- Bohé, Luis,Kammoun, Majed
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p. 747 - 751
(2007/10/03)
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- Methyltrioxorhenium-catalysed epoxidation of alkenes: Enhancement of reactivity in hexafluoro-2-propanol
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Methyltrioxorhenium-catalysed epoxidation of alkenes with hydrogen peroxide can be improved by using hexafluoro-2-propanol as a solvent. Quantitative conversions of cyclic and terminal olefins can be obtained with only 30% H2O2 and 0.1 mol% of catalyst.
- Iskra, Jernej,Bonnet-Delpon, Danièle,Bégué, Jean-Pierre
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p. 1001 - 1003
(2007/10/03)
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- Catalytic oxaziridinium-mediated epoxidation of olefins by Oxone. A convenient catalyst excluding common side reactions
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The nicely crystalline, easily prepared and handled, 3,3-dimethyl-3,4-dihydroisoquinolinium salt 6, is a convenient catalyst for the oxaziridinium-mediated epoxidation of alkenes by Oxone.
- Bohé, Luis,Kammoun, Majed
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p. 803 - 805
(2007/10/03)
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- Epoxldation of terminal alkenes with oxygen and 2-ethyl hexanal, without added catalyst or solvent
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Two terminal alkenes, 1-decene and methyl 10-undecenoate, were epoxidized with oxygen using 2-ethyl hexanal as coreactant without any added solvent. Under optimal conditions, the yield of methyl 10, 11-epoxyundecanoate was 98.7%. 2-Ethyl hexanal was oxidized mainly to 2-ethyl hexanoic acid and also formed some byproducts. The tested metal complexes retarded the epoxidation reaction slightly and increased the amount of byproducts of 2-ethyl hexanal.
- Lehtinen, Christel,Brunow, C?sta
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p. 101 - 103
(2013/09/08)
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- Manganese (III) acetate dihydrate catalyzed aerobic epoxidation of unfunctionalized olefins in fluorous solvents
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Manganese(III) acetate dihydrate is used as a catalyst for the epoxidation of various olefins with molecular oxygen/pivalaldehyde as an oxidant in perfluoro-2-butyltelrahydrofuran. Various types of olefins, including substituted styrenea, stilbenes and cyclic and acyclic alkenes were epoxidized in excellent yields at 25°C. The reaction is stereodependent. Regioselectivity is observed on epoxidation of limonene. Mono- and disubstituted olefins show interesting dichotomy in their reactivity in fluorous solvents such as perfluoro-2-butyltetrahydrofuran and 1,1,1,3,3,3- hexafluoro-2-propanol.
- Ravikumar,Barbier, Francis,Begue, Jean-Pierre,Bonnet-Delpon, Daniele
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p. 7457 - 7464
(2007/10/03)
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- Carbodiimide-Promoted Olefin Epoxidation with Aqueous Hydrogen Peroxide
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Commercially available carbodiimides in hydroxylic solvents containing hydrogen peroxide with mildly basic or acidic catalysts have been found to promote the epoxidation of olefins. A commercially available 30% aqueous solution of hydrogen peroxide serves as the oxidant for this process. The presumed reactive species is a peroxyisourea generated in situ by the addition of hydrogen peroxide to the carbodiimide.
- Majetich, George,Hicks, Rodgers,Sun, Guang-Ri,McGill, Patrick
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p. 2564 - 2573
(2007/10/03)
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- Kinetics of epoxidation of alkyl esters of undecylenic acid: Comparison of traditional routes vs. Ishii-Venturello chemistry
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Epoxidation of undecylenic acid and its methyl and ethyl esters with aqueous H2O2 was carried out by using different traditional routes, ion exchange resin, and the newly developed synergistic usage of heteropoly acids and phase transfer catalysis in a biphasic system. The so-called Ishii-Venturello chemistry was employed to develop a kinetic model. Interesting selectivities are obtained.
- Yadav,Satoskar
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p. 397 - 407
(2007/10/03)
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- Aerobic epoxidation of olefins catalysed by square-planar Cobalt(III) complexes of bis-N,N'-disubstituted oxamides and related ligands
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Three new monomeric square-planar cobalt(III) complexes of bis-N,N'-disubstituted oxamides and related ligands have been prepared. These complexes catalyse the epoxidation of tri- and disubstituted olefins with molecular oxygen/pivalaldehyde with very good yields.
- Estrada, Jesus,Fernandez, Isabel,Pedro, Jose R.,Ottenwaelder, Xavier,Ruiz, Rafael,Journaux, Yves
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p. 2377 - 2380
(2007/10/03)
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