- Hydrophobic effect and substrate specificity in reaction of thioester and amine in water
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The extent of hydrophobic effect in amidation reaction of alkyl thioester with alkylamine in water was studied. The yield of the products was primarily dependent on the alkyl group of amine. For example, the reaction of S-dodecyl dodecanethioate with dodecylamine proceeded in good yield, while the reaction did not occur with cyclohexylamine, piperidine, and dipropylamine. The effect of chain length of n-alkylamine was studied to suggest the presence of hydrophobic effect. The yield of amide also depended on the alkyl group of the thioester secondarily, but the effect was smaller than amine.
- Torihata, Atsushi,Kuroda, Chiaki
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- Alkyl perchlorates in the Ritter-type reaction. Synthesis of N-alkylamides
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The Ritter-type reaction of alkyl perchlorates with nitriles of various structures was systematically studied. The reaction has a wide scope and proceeds under extremely mild conditions without any catalysts or special activation of reagents. A structural diversity of the obtained by the Ritter-type reaction N-alkyl amides bearing small ring, double bonds, additional functional groups, aromatic and adamantane fragments, was demonstrated.
- Yashin,Markov,Sedenkova,Vasilenko,Grishin, Yu. K.,Kuznetsova,Averina
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Read Online
- Conformation, and Charge Tunneling through Molecules in SAMs
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This paper demonstrates that the molecular conformation (in addition to the composition and structure) of molecules making up self-assembled monolayers (SAMs) influences the rates of charge tunneling (CT) through them, in molecular junctions of the form AuTS/S(CH2)2CONR1R2//Ga2O3/EGaIn, where R1 and R2 are alkyl chains of different length. The lengths of chains R1 and R2 were selected to influence the conformations and conformational homogeneity of the molecules in the monolayer. The conformations of the molecules influence the thickness of the monolayer (i.e. tunneling barrier width) and their rectification ratios at ±1.0 V. When R1 = H, the molecules are well ordered and exist predominantly in trans-extended conformations. When R1 is an alkyl group (e.g., R1 H), however, their conformations can no longer be all-trans-extended, and the molecules adopt more gauche dihedral angles. This change in the type of conformation decreases the conformational order and influences the rates of tunneling. When R1 = R2, the rates of CT decrease (up to 6.3×), relative to rates of CT observed through SAMs having the same total chain lengths, or thicknesses, when R1 = H. When R1 H R2, there is a weaker correlation (relative to that when R1 = H or R1 = R2) between current density and chain length or monolayer thickness, and in some cases the rates of CT through SAMs made from molecules with different R2 groups are different, even when the thicknesses of the SAMs (as determined by XPS) are the same. These results indicate that the thickness of a monolayer composed of insulating, amide-containing alkanethiols does not solely determine the rate of CT, and rates of charge tunneling are influenced by the conformation of the molecules making up the junction.
- Belding, Lee,Root, Samuel E.,Li, Yuan,Park, Junwoo,Baghbanzadeh, Mostafa,Rojas, Edwin,Pieters, Priscilla F.,Yoon, Hyo Jae,Whitesides, George M.
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supporting information
p. 3481 - 3493
(2021/03/08)
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- Method for preparing primary and secondary amide compounds
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The invention belongs to the field of organic chemical synthesis, and particularly relates to a method for preparing primary and secondary amide compounds. The method for preparing primary and secondary amide compounds comprises the following steps of carrying out catalytic reduction on an N-substituted amide compound at 30-130 DEG C by using a protic solvent as a reduction reagent and a dichloro(p-methyl isopropylbenzene) ruthenium (II) dimer complex as a catalyst to obtain a reaction solution after the reduction reaction is finished, and carrying out post-treatment on the reaction solution to obtain the corresponding primary amide compound or secondary amide compound. According to the method for preparing the primary and secondary amide compounds, the transfer hydrogenation reaction of nitrogen-oxygen and nitrogen-carbon bonds is realized, the reaction conditions are mild and simple, the substrate application range is wide, the operation is convenient, and the corresponding primary amide compound or secondary amide compound is obtained with high efficiency and high selectivity.
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Paragraph 0178-0187
(2021/02/06)
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- Environmentally benign decarboxylative: N-, O-, and S-Acetylations and acylations
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An operationally simple and general method for acetylation and acylation of a wide variety of substrates (amines, alcohols, phenols, thiols, and hydrazones) has been reported. Meldrum's acid and its derivatives have been used as an air-stable, non-volatile, cost-effective, and easy to handle acetylating/acylating agent. Easily separable byproducts (CO2 and acetone) allowed the isolation of analytically pure acetylated products without the requirement of work-up and any chromatography. This journal is
- Ghosh, Santanu,Purkait, Anisha,Jana, Chandan K.
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supporting information
p. 8721 - 8727
(2020/12/30)
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- Overriding Intrinsic Reactivity in Aliphatic C?H Oxidation: Preferential C3/C4 Oxidation of Aliphatic Ammonium Substrates
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The site-selective C?H oxidation of unactivated positions in aliphatic ammonium chains poses a tremendous synthetic challenge, for which a solution has not yet been found. Here, we report the preferential oxidation of the strongly deactivated C3/C4 positions of aliphatic ammonium substrates by employing a novel supramolecular catalyst. This chimeric catalyst was synthesized by linking the well-explored catalytic moiety Fe(pdp) to an alkyl ammonium binding molecular tweezer. The results highlight the vast potential of overriding the intrinsic reactivity in chemical reactions by guiding catalysis using supramolecular host structures that enable a precise orientation of the substrates.
- Heilmann, Michael,Knezevic, Melina,Piccini, Giovanni Maria,Tiefenbacher, Konrad
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p. 12387 - 12391
(2020/07/04)
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- Supramolecular recognition allows remote, site-selective C-H oxidation of methylenic sites in linear amines
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Site-selective C-H functionalization of aliphatic alkyl chains is a longstanding challenge in oxidation catalysis, given the comparable relative reactivity of the different methylenes. A supramolecular, bioinspired approach is described to address this challenge. A Mn complex able to catalyze C(sp3)-H hydroxylation with H2O2 is equipped with 18-benzocrown-6 ether receptors that bind ammonium substrates via hydrogen bonding. Reversible pre-association of protonated primary aliphatic amines with the crown ether selectively exposes remote positions (C8 and C9) to the oxidizing unit, resulting in a site-selective oxidation. Remarkably, such control of selectivity retains its efficiency for a whole series of linear amines, overriding the intrinsic reactivity of C- H bonds, no matter the chain length.
- Olivo, Giorgio,Farinelli, Giulio,Barbieri, Alessia,Lanzalunga, Osvaldo,Di Stefano, Stefano,Costas, Miquel
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supporting information
p. 16347 - 16351
(2018/01/17)
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- Catalytic properties of supramolecular systems based on polyoxyethylated calixarenes and amines
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The rate of carboxylic ester cleavage by amphiphilic low-molecular-weight and polymeric amines in the presence of polyoxyethylated calix[4]arenes with different degrees of oxyethylation is determined by the formation of mixed aggregates, by the shift of pK a of the amine, and the character of the distribution of the reactants in functional micelles. All of the systems show a high substrate specificity. In the case of octyl- and decylamines, the reaction of p-nitrophenyl acetate is catalyzed and the reaction of more hydrophobic p-nitrophenyl laurate is inhibited. An opposite situation is observed in the systems based on branched polyethyleneimine: the reaction of p-nitrophenyl acetate is inhibited and the process involving p-nitrophenyl laurate is accelerated.
- Mirgorodskaya,Yatskevich,Kudryashova,Solov'Eva,Antipin,Zakharova,Konovalov
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scheme or table
p. 529 - 535
(2011/10/31)
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- Aqueous solutions of geminal alkylammonium surfactants as a medium for reactions of long-chain amines
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The formation of surfactant-hydrophobic amine mixed aggregates reduces the pK a of long-chain amines by 1-1.5 units compared with those in molecular solutions and is an important factor responsible for the high catalytic effect of the system in
- Mirgorodskaya,Kudryavtseva
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experimental part
p. 42 - 48
(2009/05/30)
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- Aminolysis of carboxylic acid esters in direct, bicontinual, and inverse microemulsions based on cetyltrimethylammonium bromide
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The reactivity of primary alkylamines in cleavage of p-nitrophenyl esters of carboxylic acids in microemulsions of different structures based on cetyltrimethylammonium bromide was studied. The aminolysis rate considerably increases in going from inverse to direct microemulsions, mainly owing to the concentration of the reactants in the boundary layer. 2005 Pleiades Publishing, Inc.
- Mirgorodskaya,Kudryavtseva,Shtykova,Bogomolova,Shtykov
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p. 1108 - 1112
(2007/10/03)
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- Anion transport in liposomes responds to variations in the anchor chains and the fourth amino acid of heptapeptide ion channels
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Seven heptapeptide derivatives have been prepared. The peptide structure is (Gly)3Xxx(Gly)3 in which Xxx stands for a variable amino acid. The amino acid variations include azetidine carboxylic acid, pipecolic acid, meta-aminobenzoic
- Ferdani, Riccardo,Pajewski, Robert,Djedovic, Natasha,Pajewska, Jolanta,Schlesinger, Paul H.,Gokel, George W.
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p. 673 - 680
(2007/10/03)
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- Electroorganic synthesis 65. Anodic homocoupling of carboxylic acids derived from fatty acids
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Fatty acid derived carboxylic acids with double bonds, hydroxy-, amino-, keto-, ester- and epoxy groups are anodically coupled to dimers (Kolbe electrolysis) in 29 to 81% yield and up to a 2.5 mol scale. Problems due to the low conductivity of fatty acid salts were overcome by the use of a flow cell with a narrow electrode gap. Fatty acids with branched alkyl chains gave dimers with interesting emulsifying properties. Dimethyl hexadecanedioate, accessible from methyl azelate, could be cyclized and further converted into homomuscone and muscone in a few steps. A commercial mixture of dimeric fatty acids (C36-dicarboxylic acids) has been coupled to give C70-diesters. Acta Chemica Scandinavica 1998. Part 64: Nielsen, M. F., Batanero, B.,.
- Weiper-Idelmann, Andreas,Aus Dem Kahmen, Martin,Schaefer, Hans J.,Gockeln, Marianne
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p. 672 - 682
(2007/10/03)
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