- Refractive index changes in polyacrylates bearing alkyl sulfur groups through the sulfur oxidation reaction
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Four polyacrylates with sulfur-containing side chains were prepared to examine the changes in refractive index (RI) induced by sulfur oxidation. Linear alkyl sulfides and alicyclic sulfides, such as 1,3-dithiolane and 1,4-dithiane, were introduced to impart large RIs to polyacrylates. Oxidation of the sulfur polymers by O3 and m-chloroperoxybenzoic acid led to the formation of the corresponding sulfoxide and sulfone polymers, respectively. Sulfur oxidation occurred completely, which was highlighted by the oxidized polymer exhibiting a refractive index comparable to a polymer that was synthesized using a sulfone monomer. The RI of the linear sulfur polymer increased and decreased due to the formation of sulfoxide and sulfone polymers, respectively. The Abbe number of the polymer with a linear sulfide side chain was 33.4, which increased to 48.7 after oxidation.
- Jang, Jae Young,Do, Jung Yun
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- Alkyl sulfonyl derivatized PAMAM-G2 dendrimers as nonviral gene delivery vectors with improved transfection efficiencies
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Amphiphilic dendrimer-based gene delivery vectors bearing peripheral alkyl sulfonyl hydrophobic tails were constructed using low-generation PAMAM-G2 as the core and functionalized by means of the aza-Michael type addition of its primary amino groups to vinylsulfone derivatives as an efficient tool for surface engineering. While the unmodified PAMAM-G2 was unable to efficiently transfect eukaryotic cells, functionalized PAMAM-G2 dendrimers were able to bind DNA at low N/P ratios, protect DNA from digestion with DNase I and showed high transfection efficiencies and low cytotoxicity. Dendrimers with a C18 alkyl chain produced transfection efficiencies up to 3.1 fold higher than LipofectAMINE 2000 in CHO-k1 cells. The dendriplexes based in functionalized PAMAM-G2 also showed the ability to retain their transfection properties in the presence of serum and the ability to transfect different eukaryotic cell lines such as Neuro-2A and RAW 264.7. Taking advantage of the vinylsulfone chemistry, fluorescent PAMAM-G2 derivatives of these vectors were prepared as molecular probes to determine cellular uptake and internalization through a clathrin-independent mechanism.
- Morales-Sanfrutos, Julia,Megia-Fernandez, Alicia,Hernandez-Mateo, Fernando,Giron-Gonzalez, Ma Dolores,Salto-Gonzalez, Rafael,Santoyo-Gonzalez, Francisco
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experimental part
p. 851 - 864
(2011/03/22)
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- New Synthetic Routes to Unsymmetrical Diorganyl Sulfides
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A number of new methods for preparing unsymmetrical diorganyl sulfides was proposed. The methods rely on generation of thiolate anions from thiols, isothiuronium salts, and disulfides in the system hydrazine hydrate-KOH, followed by alkylation of the anions with alkyl halides. The hydrazine hydrate plays the role of medium and reducing agent, which prevents side thiol oxidation. The yield of sulfides reaches 98%. The reaction products are readily separated from the aqueous-hydrazine layer and purified by distillation. The yield of sulfides is reduced by a deficit of alkali and by increasing chain length and functionalization of alkyl groups in the alkyl halide. The reactivity of alkyl halides is independent of the nature of the halogen. From isothiuronium salts, 2-pyridyl sulfides were obtained in the highest yields.
- Deryagina,Korchevin,Papernaya
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p. 812 - 815
(2007/10/03)
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- SYNTHESIS OF POLYSULFIDES, SULFOXIDES AND SULFONES CONTAINING REACTIVE GROUPS
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Preparation of polysulfides, sulfoxides and sulfones (containing reactive groups: OH, Cl, COOR, CN, SO3Na) are presented; 13C chemical shifts of these compounds have been recorded.Keywords: Sulfide; sulfoxide; sulfone; chlorosulfide; 1H NMR; 13C NMR.
- Aberkane, O.,Mieloszynski, J. L.,Robert, D.,Born, M.,Paquer, D.
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p. 245 - 256
(2007/10/02)
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- Chemical Structure and Thermodynamics of Amphiphile Solutions. 1. Solubility of Alkylthiooligooxyethylene Glycols in Water
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Solubilities of individual alkylthiooligooxyethylene glycols CnH2n+1SCH2CH2(OCH2CH2)zOH (alkyl: n-C4H9, ..., n-C9H19; and z = 0, ..., 3) in water at 298.15 K have been determined.A quantitative correlation has been found between the standard free energy for transfer from aqueous solution to pure liquid phase, ΔGot, and the structure of the studied sulfides and of oligooxyethylenated alcohols as well by using the appropriate multiple regression equation.It has been found that the thioethylene group, -SCH2CH2-, is hydrophobic.The standard free energy contribution, ΔGot, is -3.4 kJ mol-1.The interaction between methylene groups, -CH2-, of the hydrocarbon chain and the -OCH2CH2- groups of the oligooxyethylene chain is statistically significant and has an influence on the total value of ΔGot.Furthermore, the ΔGot and ΔGot are not constant.For the sulfides studied, ΔGot increases linearly with hydrocarbon chain length.For example, ΔGot for the series of butyl and nonyl derivatives is +0.24 and +0.81 kJ mol-1, respectively.The ΔGot for the series of alkyl-2-hydroxyethyl sulfides (z=0) and alkylthiotetraoxyethylene glycol (z=3) is -3.43 and -3.10 kJ mol-1, and the ΔGot and ΔGot for the group of oxyethylenated alcohols are +0.53 and -3.13 kJ mol-1, respectively.
- Sokolowski, Adam
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p. 8223 - 8226
(2007/10/02)
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- REACTIONS OF OXIRANES WITH ALKYLTHIOLS
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Alkyl-2-hydroxyalkyl sulfides and their oxyalkylenated adducts were obtained in the reaction of oxirane or methyloxirane with C4-C12 alkylthiols in presence of basic or acidic catalysts.The sulfides were further oxidized to sulfoxides and sulfones.
- Chlebicki, Jan,Cichacz, Zbigniew
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p. 485 - 494
(2007/10/02)
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- Organotin-containing composition for the stabilization of polymers of vinyl chloride
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An organotin-containing composition for the stabilization of polymers or copolymers of vinyl chloride in which there is incorporated a stabilizing amount of an organotin compound containing at least two tin atoms and which is a mercapto, hydroxy or alkoxy substituted ester of a mercapto acid substituted organotin mercapto acid diester.
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- REACTION OF VINYL ESTERS OF α,β-UNSATURATED CARBOXYLIC ACIDS WITH SECONDARY AMINES
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It was established that the double bond of the acrylic system is more reactive in the reactions of vinyl acrylate and allyl acrylate with secondary amines and that the reaction of secondary amines with vinyl trans-crotonate and cinnamate takes place regioselectively at the double bond of the vinyloxy group.Methods were found for the production of vinyl and allyl β-substituted aminopropionates and 2-alkylaminoethyl trans-crotonate and trans-cinnamate.
- Komarova, L. I.,Lomanovskaya, T. D.,Komarov, N. V.
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p. 1624 - 1627
(2007/10/02)
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- Gas-Liquid Phase-transfer Synthesis of Phenyl Ethers and Sulphides with Carbonate as Base and Carbowax as Catalyst
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When a mixture of a phenol (or thiol) and an alkyl halide is passed, in the gaseous state, through a solid bed of potassium carbonate (or sodium hydrogencarbonate) and catalytic amounts of Carbowax 6000, contained in a glass column at 170 deg C, the corresponding ethers (or sulphides) may be collected at the outlet.The Carbowax acts in a similar manner to the crown ethers used in solid-liquid phase-transfer catalysis.The potassium carbonate-Carbowax combination allows the generation of anions up to pKa of ca. 12.The catalysis mechanism is discussed and the synthesis of several ethers and thioethers is reported, some of which are obtained only with difficulty by normal liquid-liquid phase-transfer catalysis.
- Angeletti, Enrico,Tundo, Pietro,Venturello, Paolo
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p. 1137 - 1142
(2007/10/02)
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- SYNTHESIS AND SOME TRANSFORMATIONS OF VINYL β-ACETYL- AND β-BENZOYLACRYLATES
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Vinyl β-acetyl- and β-benzoylacrylates were obtained by transvinylation with vinyl acetate in the presence of the catalyst Hg(OCOCH3)2.BF3.O(C2H5)2.It was shown that the reactions with bromine, mercuric acetates, and butyl hydrosulfide at the vinyloxy group are regioselective.
- Komarova, L. I.,Zhuravlev, S. V.,Sal'nikova, L. V.
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p. 1422 - 1425
(2007/10/02)
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