- Reversible zwitterionic liquids, the reaction of alkanol guanidines, alkanol amidines, and diamines with CO2
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Alkanolamidines, alkanolguanidines and diamines each react with CO 2 to form reversible zwitterionic liquids. CO2 is chemically bound to the alcohol on alkanolamidines and alkanolguanidines as zwitterionic alkylcarbonates, while CO2 is chemically bound on diamines as zwitterionic carbamates. All three classes of zwitterionic liquids could be reverted to their non-ionic forms by thermally stripping the CO 2 at temperatures near 50 °C, while one derivative was found to irreversibly form a cyclic carbonate.
- Heldebrant, David J.,Koech, Phillip K.,Ang, M. Trisha C.,Liang, Chen,Rainbolt, James E.,Yonker, Clement R.,Jessop, Philip G.
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- Selective oxidation of exogenous substrates by a bis-Cu(III) bis-oxide complex: Mechanism and scope
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Cu(III)2(μ-O)2 bis-oxides (O) form spontaneously by direct oxygenation of nitrogen-chelated Cu(I) species and constitute a diverse class of versatile 2e?/2H+ oxidants, but while these species have attracted attention as biomimetic models for dinuclear Cu enzymes, reactivity is typically limited to intramolecular ligand oxidation, and systems exhibiting synthetically useful reactivity with exogenous substrates are limited. OTMPD (TMPD = N1, N1, N3, N3-tetramethylpropane-1,3-diamine) presents an exception, readily oxidizing a diverse array of exogenous substrates, including primary alcohols and amines selectively over their secondary counterparts in good yields. Mechanistic and DFT analyses suggest substrate oxidation proceeds through initial axial coordination, followed by rate-limiting rotation to position the substrate in the Cu(III) equatorial plane, whereupon rapid deprotonation and oxidation by net hydride transfer occurs. Together, the results suggest the selectivity and broad substrate scope unique to OTMPD are best attributed to the combination of ligand flexibility, limited steric demands, and ligand oxidative stability. In keeping with the absence of rate-limiting C–H scission, OTMPD exhibits a marked insensitivity to the strength of the substrate Cα–H bond, readily oxidizing benzyl alcohol and 1-octanol at near identical rates.
- Large, Tao A.G.,Mahadevan, Viswanath,Keown, William,Stack, T. Daniel P.
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p. 782 - 792
(2019/01/03)
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- A complete series of 6-deoxy-monosubstituted tetraalkylammonium derivatives of α-, β-, and γ-cyclodextrin with 1, 2, and 3 permanent positive charges
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An efficient synthetic route toward the preparation of a complete series of monosubstituted tetraalkylammonium cyclodextrin (CD) derivatives is presented. Monotosylation of native CDs (α-, β-, γ-) at position 6 gave the starting material. Reaction of monotosylate (mono-Ts-CD) with 45% aqueous trimethylamine gave CDs substituted with one cationic functional group in a single step. Derivatives equipped with a substituent containing two cationic sites separated by an ethylene or a propylene linker were prepared by reacting mono-Ts-CD with neat N,N,N'-trimethylethane-1,2-diamine or N,N,N'- trimethylpropane-1,3-diamine and subsequent methylation by CH3I in good yields. Finally, analogues bearing a moiety with three tetraalkylammonium sites were synthesized by reacting mono-Ts-CD with bis(3-aminopropyl)amine and subsequent methylation. The majority of the presented reactions are very straightforward with a simple work-up, which avoids the need of chromatographic separation. Thus, these reactions are suitable for the multigram-scale production of monosubstituted cationic CDs. 2014 Popr et al;.
- Popr, Martin,Hybelbauerova, Simona,Jindrich, Jindrich
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supporting information
p. 1390 - 1396
(2014/07/22)
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- Tetracyclic benzimidazole derivatives and combinatorial libraries thereof
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The present invention relates to novel tetracyclic benzimidazole derivative compounds of the following formula: wherein R1to R10have the meanings described in here. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing tetracyclic benzimidazole derivative compounds.
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- METHOD FOR TREATING CHRONIC PAIN USING MEK INHIBITORS
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The invention features a method for treating chronic pain using a compound selected from formulae (I), (II)A, (I)B and (I)C.
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- Long-range anisotropic effects of long chain amides
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In 1H-NMR spectra of amids with long-chain aliphatic N-substituents one observes - despite of the free mobility of the aliphatic chain - splitting of the signals of the terminal methyl groups which is caused by the hindered rotation of the amide bond. - Keywords: Amides; Hindered rotation; 1H-NMR
- Budzikiewicz, Herbert,Vieth, Peter-Eric,Krueger, Uwe
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p. 825 - 840
(2007/10/02)
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