1462-55-1Relevant academic research and scientific papers
Extended Pummerer fragmentation mediated by carbon dioxide and cyanide
Liu, Jian,Kragh, Rasmus R.,Kamounah, Fadhil S.,Lee, Ji-Woong
supporting information, (2020/10/30)
Pummerer rearrangement reactions generate sulfur (II) oxidation state from sulfur (IV) starting materials in the presence of activating reagents. We found unprecedented transformation of vinyl sulfoxide; disulfide formation reactions mediated by atmospheric pressure of carbon dioxide in extended Pummerer rearrangement reactions. Only under CO2 atmosphere, we observed moderate to high yields of disulfide starting from sulfur (IV) starting materials. Investigations on the reaction mechanism revealed that the degradation of the starting materials and the products was significant in the absence of CO2. Further evidence for the suggested reaction mechanism was obtained by a cross-over experiment and a radical trapping reagent.
A mechanism of alkali metal carbonates catalysing the synthesis of β-hydroxyethyl sulfide with mercaptan and ethylene carbonate
Liu, Dongliang,Thomas, Tiju,Gong, Hong,Li, Fei,Li, Qiang,Song, Lijuan,Azhagan, Tamil,Jiang, Heng,Yang, Minghui
, p. 9367 - 9374 (2019/11/13)
The reaction of β-hydroxyethylation is essential to the current practice of organic chemistry. Here, we proposed a new and green route to synthesize 2-hydroxyethyl n-alkyl sulfide with n-alkyl mercaptan and ethylene carbonate (EC) in the presence of alkali carbonates as catalysts and revealed the mechanism by experiments and theoretical calculations. The reaction reported proceeds rapidly with high yields when it is performed at 120 °C and the catalytic loading is ～1 mol%. This protocol is applicable to other mercaptans to synthesize the corresponding β-hydroxyethyl sulfide. Density functional theory-based calculations show the energy profile for the reaction pathway. The rate-determining step is the ring-opening of EC. A negatively charged O atom of alkali carbonates approaches the S atom of -SH under the influence of hydrogen bonds. An activated S atom that carries more negative charge serves as a nucleophilic reagent and assists in the ring-opening of EC by reducing the Mayer bond orders of the C1-O1 bond in EC. Alkali cations also contribute to the C1-O1 bond cleavage. The energy barrier for the ring-opening of EC decreases with the decrease of electronegativity of alkali cations. Subsequent transference of a H atom leads to the formation of β-hydroxyethyl sulfide, the dissociation of CO2 and the reduction of K2CO3
Sulfur makes the difference: Synthesis and mesomorphic properties of novel thioether-functionalized imidazolium ionic liquid crystals
Mansueto, Markus,Kre?, Katharina Christina,Laschat, Sabine
, p. 6258 - 6264 (2015/03/30)
Novel thioether-linked imidazolium ionic liquid crystals were synthesized starting from methyl 2-mercaptoacetate. The mesomorphic properties were determined by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction. All mesogens displayed smectic A mesophase geometries with strongly interdigitated bilayer structures. Comparison of the thioether-linked imidazolium salts with the corresponding amine- and amide-linked imidazolium salts as well as simple N-alkyl-imidazolium salts showed that both mesophase width and stability increased with increasing softness of the linking unit, thus indicating the beneficial effect of sulfur. Additionally, an increase of the length of the linking unit decreased the interdigitation of the alkyl chains.
Alkyl sulfonyl derivatized PAMAM-G2 dendrimers as nonviral gene delivery vectors with improved transfection efficiencies
Morales-Sanfrutos, Julia,Megia-Fernandez, Alicia,Hernandez-Mateo, Fernando,Giron-Gonzalez, Ma Dolores,Salto-Gonzalez, Rafael,Santoyo-Gonzalez, Francisco
experimental part, p. 851 - 864 (2011/03/22)
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.
Trifluoromethyl ketone analogs as selective cPLA2 inhibitors
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, (2008/06/13)
Selective inhibitors of the cPLA2enzymes are provided which are of use in controlling a wide variety of inflammatory diseases. The inhibitors of the present invention have the general formula where (R′), p, D, Y, Z, Ra, Rband A are as defined in the specification.
Trifluoromethyl ketone analogs as selective cPLA2 inhibitors
-
, (2008/06/13)
Selective inhibitors of the cPLA2enzymes are provided which are of use in controlling a wide variety of inflammatory diseases. The inhibitors of the present invention have the general formula
