- Asymmetric synthesis and biological evaluation of natural or bioinspired cytotoxic C 2-symmetrical lipids with two terminal chiral alkynylcarbinol pharmacophores
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Bidirectional syntheses of C2-symmetrical lipids embedding two terminal alkynylcarbinol pharmacophores are reported. Naturally occurring chiral alkenylalkynylcarbinol units were generated using Pus procedure for enantioselective addition of terminal alkynes to aldehydes, allowing the first asymmetric synthesis of (3R,4E,16E,18R)-icosa-4,16-diene-1,19-diyne-3,18-diol, isolated from Callyspongia pseudoreticulata. Two synthetic analogues embedding the recently uncovered (S)-dialkynylcarbinol pharmacophore were secured using Carreiras procedure adapted to ynal substrates. The dramatic effect of the carbinol configuration on cytotoxicity was confirmed with submicromolar IC50 values against HCT116 cells.
- Listunov, Dymytrii,Fabing, Isabelle,Saffon-Merceron, Nathalie,Gaspard, Hafida,Volovenko, Yulian,Maraval, Valérie,Chauvin, Remi,Génisson, Yves
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- Acid monolayer functionalized iron oxide nanoparticles as catalysts for carbohydrate hydrolysis
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Superparamagnetic iron oxide nanoparticles were functionalized with a quasi-monolayer of 11-sulfoundecanoic acid and 10-phosphono-1-decanesulfonic acid ligands to create separable solid acid catalysts. The ligands are bound through carboxylate or phosphonate bonds to the magnetite core. The ligand-core bonding surface is separated by a hydrocarbon linker from an outer surface with exposed sulfonic acid groups. The more tightly packed monolayer of the phosphonate ligand corresponded to a higher sulfonic acid loading by weight, a reduced agglomeration of particles, a greater tendency to remain suspended in solution in the presence of an external magnetic field, and a higher catalytic activity per sulfonic acid group. The particles were characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM), potentiometric titration, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), inductively coupled plasma optical emission spectrometry (ICP-OES), and dynamic light scattering (DLS). In sucrose catalysis reactions, the phosphonic-sulfonic nanoparticles (PSNPs) were seen to be incompletely recovered by an external magnetic field, while the carboxylic-sulfonic nanoparticles (CSNPs) showed a trend of increasing activity over the first four recycle runs. The activity of the acid-functionalized nanoparticles was compared to the traditional solid acid catalyst Amberlyst-15 for the hydrolysis of starch in aqueous solution. Catalytic activity for starch hydrolysis was in the order PSNPs > CSNPs > Amberlyst-15. Monolayer acid functionalization of iron oxides presents a novel strategy for the development of recyclable solid acid catalysts.
- Ikenberry, Myles,Pena, Leidy,Wei, Daming,Wang, Hongwang,Bossmann, Stefan H.,Wilke, Trenton,Wang, Donghai,Komreddy, Venugopal R.,Rillema, D. Paul,Hohn, Keith L.
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- Self-aggregation of synthesized novel bolaforms and their mixtures with sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) in aqueous medium
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Bolaforms B1, B2, and B3 of the formulas, Br-Me3N+(CH2)10N +Me3Br-, Br-Me3N +(CH2)10OH, and Br-Me 3N+(CH2)10COO-Na +, respectively, were synthesized, and their properties in the bulk as well as at the air/aqueous NaBr (10 mM) solution interface have been studied. Their interactions with sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) also have been investigated. Tensiometry, conductometry, spectrophotometry, and microcalorimetry techniques were used for characterization and estimation. Both pure bolaforms and their mixtures with SDS and CTAB have been found to self-aggregate, forming micelles in solution. The mixed systems of bolaform and SDS have been observed to form both micelles and vesicles. Their mutual interactions were synergistic, which at the interface was more spontaneous than in the bulk. The interfacial and bulk compositions of the mixed binary systems (bolaform and SDS or CTAB) with their associated interaction parameters have been estimated from the Rosen interaction model and the regular solution theory of Rubingh, respectively. The formed vesicles have been found to entrap the water-soluble dye, bromophenol blue, and the dye solubilized vesicles of B1-SDS and B2-SDS completely eluted out of the sephadex column proving their formation. A rough estimation of the size and polydispersity index of the formed micelles and vesicles has been made from DLS measurements.
- Maiti, Kajari,Mitra, Debolina,Mitra, Rajendra N.,Panda, Amiya K.,Das, Prasanta K.,Rakshit, Animesh K.,Moulik, Satya P.
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- PROCESS FOR THE PREPARATION OF ORGANIC BROMIDES
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The present invention provides a process for the preparation of organic bromides, by a radical bromodecarboxylation of carboxylic acids with a bromoisocyanurate.
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Paragraph 00169; 00172
(2017/07/28)
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- Silver-Catalyzed Decarboxylative Bromination of Aliphatic Carboxylic Acids
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The silver-catalyzed Hunsdiecker bromination of aliphatic carboxylic acids is described. With Ag(Phen)2OTf as the catalyst and dibromoisocyanuric acid as the brominating agent, various aliphatic carboxylic acids underwent decarboxylative bromination to provide the corresponding alkyl bromides under mild conditions. This method not only is efficient and general but also enjoys wide functional group compatibility. An oxidative radical mechanism involving Ag(II) intermediates is proposed.
- Tan, Xinqiang,Song, Tao,Wang, Zhentao,Chen, He,Cui, Lei,Li, Chaozhong
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supporting information
p. 1634 - 1637
(2017/04/11)
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- Catalytic Access to Alkyl Bromides, Chlorides and Iodides via Visible Light-Promoted Decarboxylative Halogenation
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Herein is reported the catalytic, visible light-promoted, decarboxylative halogenation (bromination, chlorination, and iodination) of aliphatic carboxylic acids. This operationally-simple reaction tolerates a range of functional groups, proceeds at room temperature, and is redox neutral. By employing an iridium photocatalyst in concert with a halogen atom source, the use of stoichiometric metals such as silver, mercury, thallium, and lead can be circumvented. This reaction grants access to valuable synthetic building blocks from the large pool of cheap, readily available carboxylic acids.
- Candish, Lisa,Standley, Eric A.,Gómez-Suárez, Adrián,Mukherjee, Satobhisha,Glorius, Frank
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supporting information
p. 9971 - 9974
(2016/07/19)
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- Process intensification-assisted conversion of α,ω-alkanediols to dibromides
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The increasingly widespread applications of α,ω-dibromides motivated development of a scalable, inexpensive process to rapidly convert selected α,ω-alkanediols to the corresponding dibromides. Diols were heated with only 48% aq HBr and an organic solvent, using a Dean-Stark apparatus modified to fractionate the azeotropic distillate, thereby maintaining a higher HBr concentration and reaction rate in the pot. Intensified distillation also increased the reaction rate. Various other substrate, solvent, and parameter effects have been discovered and rationalized.
- Mekala, Shekar,Hahn, Roger C.
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supporting information
p. 630 - 632
(2015/03/03)
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- Ti-catalyzed homolytic opening of ozonides: A sustainable C-C bond-forming reaction
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The unprecedented homolytic opening of ozonides promoted and catalyzed by titanocene(III) is reported. This novel reaction proceeds at room temperature under neutral, mild conditions compatible with many functional groups and provides carbon radicals suitable to form C-C bonds via both homocoupling and cross-coupling processes. The procedure has been advantageously exploited for the straightforward synthesis of the natural product brittonin A.
- Rosales, Antonio,Munoz-Bascon, Juan,Lopez-Sanchez, Cristobal,Alvarez-Corral, Miriam,Munoz-Dorado, Manuel,Rodriguez-Garcia, Ignacio,Oltra, J. Enrique
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p. 4171 - 4176
(2012/06/18)
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- Synthetic route discovery and introductory optimization of a novel process to idebenone
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An environmentally benign, convenient, high yielding, and cost-effective synthesis leading to idebenone is disclosed. The synthesis includes a bromination process for the preparation of 2-bromo-3,4,5-trimethoxy-1- methylbenzene, a protocol for the Heck cross-coupling reaction using either thermal or microwave heating, olefin reduction by palladium catalyzed hydrogenation, and a green oxidation protocol with hydrogen peroxide as oxidant to achieve the benzoquinone framework. The total synthesis is composed of six steps that provide an overall yield of 20% that corresponds to a step yield of 76%.
- Tsoukala, Anna,Bjorsvik, Hans-Rene
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experimental part
p. 673 - 680
(2011/12/01)
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- An optimized process to 10-bromo-1-decanol
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A multivariate design and optimization study for the synthesis of the bromoalkanol 10-bromo-1-decanol using decane-1,10-diol as substrate is reported. The bromination process was supported by the phase transfer catalyst tetrabutylammonium bromide with aqueous HBr (48%) as the brominating reagent. The optimized batch protocol provided a yield of 64% of 10-bromo-1-decanol 2 TM with a conversion of 80%, and 10% of the dibrominated alkane 1,10-dibromodecane 3, a characteristic byproduct, was formed.
- Spaccini, Raffaele,Tsoukala, Anna,Liguori, Lucia,Punta, Carlo,Borsvik, Hans-Rene
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experimental part
p. 1215 - 1220
(2011/04/16)
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- A photoirradiative phase-vanishing method: Efficient generation of HBr from alkanes and molecular bromine and its use for subsequent radical addition to terminal alkenes
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A triphasic phase-vanishing (PV) system comprised of an alkane, perfluorohexanes, and bromine was successfully combined by photoirradiation to efficiently generate hydrogen bromide, which underwent radical addition with 1-alkenes in the hydrocarbon layer to afford terminal bromides in high yields. Georg Thieme Verlag Stuttgart.
- Matsubara, Hiroshi,Tsukida, Masaaki,Ishihara, Daisuke,Kuniyoshi, Kenji,Ryu, Ilhyong
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experimental part
p. 2014 - 2018
(2010/10/02)
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- First syntheses of model long-chain trichloro[ω-(trimethylsilyl)alkynyl]silanes suitable for self-assembled monolayers on silicon surfaces
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The preparation of the title compounds involves the introduction of the required Me3SiC{triple bond, long}C and trichlorosilyl groups at the termini of the alkyl chain via derivatization of easily accessible and inexpensive materials/reagents. Trichloro[ω-(trimethylsilyl)alkynyl]silanes are useful for the linkage to a hydroxylated silicon surface for multilayer formation and for further chemical modification of the tail group of the monolayer.
- Banaszak, Estelle,Xu, Li-Wen,Bardeau, Jean-Fran?ois,Castanet, Anne-Sophie,Mortier, Jacques
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body text
p. 3961 - 3966
(2009/09/30)
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- Rubrenolide, total synthesis and revision of its reported stereochemical structure
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In this paper the synthesis of the natural product rubrenolide is presented. Due to an error in the original proposed stereochemical structure of rubrenolide, the synthesis was not straightforward. Application of the photo-induced rearrangement of an appropriate epoxy diazomethyl ketone gave access to the precursor lactone with an ee of 91%. Coupling of this lactone with (4S)-2,2-dimethyl-[1,3]-dioxolane-4-carbaldehyde gave, after some additional steps, the final product that was identical with an authentic sample of the natural product.
- Thijs,Zwanenburg
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p. 5237 - 5252
(2007/10/03)
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- Effect of cyclohexenonic long chain fatty alcohols on neurite outgrowth. Study on structure-activity relationship
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Four series of long chain fatty alcohols bearing a cyclohexenone moiety in addition to a ω-alkanol side chain were synthesized using 'Umpolung' reactivity strategy. Their effect on neurite outgrowth was evaluated by means of fetal rat neurons in culture. The length of the ω-hydroxy side chain is a crucial factor for biological activity.
- Girlanda-Junges, Celine,Keyling-Bilger, Florence,Schmitt, Gaby,Luu, Bang
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p. 7735 - 7748
(2007/10/03)
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- A New and Efficient One-Pot Preparation of Alkyl Halides From Alcohols
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Primary alkanols and 2-alkenols are converted into the corresponding halides in high yield by a one-pot, two-step reaction via transformation into intermediate trifluoroacetates followed by nucleophilic substitution with lithium halides.
- Camps, Francisco,Gasol, Vicens,Guerrero, Angel
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p. 511 - 512
(2007/10/02)
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In dimethylformamide or N-methylpyrrolidone the Ni-bipyridyl system catalyses the electrochemical reduction of functionalised or non-functionalised aliphatic halides. High yields of dimeric products are obtained besides primary mono- or di-bromides. Analysis of the reaction products shows the formation of dialkylnickel which can be isolated by coulometry. This species acts as a reducing agent for aliphatic halides.
- Mabrouk, Salah,Pellegrini, Sylvain,Folest, Jean-Claude,Rollin, Yolande,Perichon, Jacques
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p. 391 - 400
(2007/10/02)
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- Process for preparing olefinic aldehydes
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A process for the preparation of olefinic aldehydes and intermediates is disclosed. The condensation of an α,ω-dihalide with a metal acetylide gives an acetylenic halide which can be reduced to give an olefinic halide, then oxidized to give the desired olefinic aldehyde or the acetylenic halide can be oxidized first to give an acetylenic aldehyde and then reduced to give the desired olefinic aldehyde.
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