1122-81-2Relevant academic research and scientific papers
Sunfish amphiphiles: Conceptually new carriers for DNA delivery
Hulst, Ron,Muizebelt, Inouk,Oosting, Peter,Van Der Pol, Cornelia,Wagenaar, Anno,Smisterova, Jarmila,Bulten, Erna,Driessen, Cecile,Hoekstra, Dick,Engberts, Jan B. F. N.
, p. 835 - 849 (2004)
A conceptually new class of cationic amphiphiles, Sunfish amphiphiles, designed for the delivery of genes into cells is introduced. Sunfish amphiphiles have two hydrophobic tails, connected at the 4- and the N-position to the cationic pyridinium headgroup. Two extreme morphologies visualised by backfolding and combining of both tails at one site (matching situation) or unfolding of the tails at distinct interaction sites at biological membranes will lead to considerable differences in morphological behaviour. The underlying rationale allows controlled release by using this morphological alteration of the Sunfish/helper-lipid/DNA complex (lipoplex). The often-excellent transfection efficiencies are probably related to these morphological changes. In addition, the Sunfish amphiphiles possess low toxicities, resulting in high cell survival after internalisation. The underlying rationale, design, synthesis and in vitro transfection potential are discussed in detail. Moreover, some physico-chemical characteristics of the Sunfish amphiphiles have been studied. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Photocatalytic Hydromethylation and Hydroalkylation of Olefins Enabled by Titanium Dioxide Mediated Decarboxylation
Zhu, Qilei,Nocera, Daniel G.
supporting information, p. 17913 - 17918 (2020/12/04)
A versatile method for the hydromethylation and hydroalkylation of alkenes at room temperature is achieved by using the photooxidative redox capacity of the valence band of anatase titanium dioxide (TiO2). Mechanistic studies support a radical-based mechanism involving the photoexcitation of TiO2 with 390 nm light in the presence of acetic acid and other carboxylic acids to generate methyl and alkyl radicals, respectively, without the need for stoichiometric base. This protocol is accepting of a broad scope of alkene and carboxylic acids, including challenging ones that produce highly reactive primary alkyl radicals and those containing functional groups that are susceptible to nucleophilic substitution such as alkyl halides. This methodology highlights the utility of using heterogeneous semiconductor photocatalysts such as TiO2 for promoting challenging organic syntheses that rely on highly reactive intermediates.
Efficient Diastereoselective Three-Component Synthesis of Pipecolic Amides
van der Heijden, Gydo,van Schaik, Timo B.,Mouarrawis, Valentinos,de Wit, Martin J. M.,Velde, Christophe M. L. Vande,Ruijter, Eelco,Orru, Romano V. A.
supporting information, p. 5313 - 5325 (2019/06/10)
An efficient Ugi-type three-component reaction (U-3CR) for the synthesis of pipecolic amides is reported. The U-3CR between electronically diverse isocyanides, carboxylic acids and 4-substituted Δ1-piperideines proceeds in a highly diastereoselective fashion. The Δ1-piperideines are obtained by NCS-mediated oxidation of the corresponding 4-substituted piperidines, which in turn are generated by an efficient two-step procedure involving the alkylation of 4-picoline and subsequent catalytic hydrogenation of the pyridine ring. We demonstrate the utility of this U-3CR, in combination with the convertible isocyanide 2-bromo-6-isocyanopyridine, in the synthesis of the anticoagulant argatroban.
Process for recovering oxygenated organic compounds from dilute aqueous solutions employing liquid extraction media
-
, (2008/06/13)
A thermally efficient process for recovering an oxygenated organic material, such as ethanol, present in dilute aqueous solution is disclosed which comprises contacting said dilute aqueous solution with at least one inert extractant which is liquid at ambient temperature and pressure, said extractant being selected from the group consisting of unsubstituted and substituted cyclic secondary amines and unsubstituted and substituted aromatic cyclic amines having a distribution coefficient of at least about 0.70 or a separation factor of at least about 1.0. The invention further provides a process for obtaining substantially anhydrous oxygenated organic material from a dilute aqueous solution thereof in which the stream is subjected to liquid-liquid extraction to provide an oxygenated organic material poor raffinate phase and an oxygenated organic material rich extract phase, the oxygenated organic material present in said latter phase is concentrated in a rectifying column to provide an aqueous oxygenated organic material of high concentration and, if desired or necessary, the concentrated stream is azeotropically distilled in an anhydrous column operated under substantially superatmospheric pressure with thermal values recovered from said anhydrous column being used to satisfy part of all of the thermal operating requirements of the rectifying column.
A Convenient Method for the Regioselective Synthesis of 4-Alkyl(aryl)pyridines Using Pyridinium Salts
Akiba, Kin-ya,Iseki, Yuji,Wada, Makoto
, p. 1994 - 1999 (2007/10/02)
RCu.BF3 reacted with 1-ethocycarbonylpyridinium chloride at the 4-position with almost complete regioselectivity (>99percent) to afford the corresponding 1,4-dihydropyridine derivatives in high yields (81-94percent).The dihydropyridines were oxidized by oxygen to give 4-alkyl(aryl)pyridines (38-68percent).Grignard reagents also reacted with 1-t-butyldimethylsilylpyridinium triflate with almost complete regioselectivity (>99percent) to afford the corresponding 1,4-dihydropyridines, which were easily oxidized to give 4-substituted pyridines in higher yields than above (58-70percent).
Process for recovering ethanol from dilute aqueous solutions employing liquid extraction media
-
, (2008/06/13)
A thermally efficient process for recovering ethanol present in dilute aqueous solution is disclosed which comprises contacting said dilute aqueous ethanol solution with at least one inert extractant which is liquid at ambient temperature and pressure, said extractant being selected from the group consisting of unsubstituted and substituted cyclic secondary amines and unsubstituted and substituted aromatic cyclic amines having a distribution coefficient of at least about 0.70 or a separation factor of at least about 1.0. The invention further provides a process for obtaining substantially anhydrous ethanol from a dilute aqueous ethanol solution in which the ethanol stream is subjected to liquid-liquid extraction to provide an ethanol-poor raffinate phase and an ethanol-rich extract phase, the ethanol present in said latter phase is concentrated in a rectifying column to provide an aqueous ethanol of high proof and the concentrated ethanol is azeotropically distilled in an anhydrous column operated under substantially superatmospheric pressure with thermal values recovered from said anhydrous column being used to satisfy part of all of the thermal operating requirements of the rectifying column.
Catalytic Reactions of Pyridines. V. Alkylation of α-, β-, and γ-Picolines with Alcohols catalyzed by Ammonium Halides
Kashiwagi, Hiroshi,Enomoto, Saburo
, p. 2213 - 2218 (2007/10/02)
A new method was found for the homogeneous liquid-phase alkylation of α-, β-, and γ-picolines with either methanol or ethanol.Addition of a catalytic amount of an ammonium halide to a mixture of a picoline and an alcohol resulted in a great increase in the yields of both side-chain and α-alkylated derivatives of the starting picoline when the reaction was carried out at 320-335 deg C in an atmosphere of nitrogen.The higher the reaction temperature, the greater the yields of side-chain alkylated derivatives became.In practice, this alkylation gave 2-ethylpyridine, and 2,6-lutidine from α-picoline with methanol, 3-ethylpyridine and 2,5-lutidine from β-picoline from methanol, 4-ethylpyridine and 2,4-lutidine from γ-picoline with methanol, 2-propylpyridine and 2-ethyl-6-methylpyridine from α-picoline with ethanol, 2-ethyl-5-methylpyridine from β-picoline with ethanol, and 4-propylpyridine and 2-ethyl-4-methylpyridine from γ-picoline with ethanol.Keywords-alkylation; catalyst; ammonium halide; α-picoline; β-picoline; γ-picoline; ethylpyridine; propylpyridine; methanol; ethanol
Synthetic Applications of N-N Linked Heterocycles. Part 13. N-(2,5-Dimethylpyrrol-1-yl)pyridinium Salts in the Synthesis of 4-Alkyl and 4-Aryl-pyridines via Regiospecific Attack of Grignard Reagents and Organolithium Compounds.
Katritzky, Alan R.,Beltrami, Hector,Sammes, Michael P.
, p. 1684 - 1696 (2007/10/02)
The reaction between N-(2,5-dimethylpyrrol-1-yl)pyridinium salts and alkyl- or aryl-Grignard reagents, or organolithium compounds, gives regiospecifically 1,4-dihydro-intermediates.These may be isolated and decomposed under free-radical conditions to give moderate to good yields of 4-alkyl- and 4-aryl-pyridines.Results are compared with those obtained from a related reaction sequence involving N-(2,6-dimethyl-4-oxopyridin-1-yl)pyridinium salts.
Synthetic Applications of N-N Linked Heterocycles. Part 7. The Preparation of 4-Alkyl- and 4-Aryl-pyridines by Regiospecific Attack of Grignard Reagents γ to Quaternary Nitrogen in N-(2,6-Dimethyl-4-oxopyridin-1-yl)pyridinium Salts
Katritzky, Alan R.,Beltrami, Hector,Sammes, Michael P.
, p. 2480 - 2484 (2007/10/02)
N-(2,6-Dimethyl-4-oxopyridin-1-yl)pyridinium salts (4), new reagents for the regiospecific synthesis of 4-substituted pyridines, give moderate to high yields of 4-alkyl- and 4-aryl-pyridines (8) - (10) on reaction with Grignard reagents.The scope and limitations on the reaction, which proceeds via 1,4-dihydro-intermediates (5) - (7), are explored.No 2-substituted pyridines were detected.Some reactions with organolithium compounds are also described.
