- Ion channel formation from a calix[4]arene amide that binds HCl
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The ion transport activity of calix[4]arene tetrabutylamide 1,3-alt 2 was studied in liposomes, planar lipid bilayers, and HEK-293 cells. These experiments, when considered together with 1H NMR and X-ray crystallography data, indicate that calix[4]arene tetrabutylamide 2 (1) forms ion channels in bilayer membranes, (2) mediates ion transport across cell membranes at positive holding potential, (3) alters the pH inside liposomes experiencing a Cl- gradient, and (4) shows a significant Cl-/SO42- transport selectivity. An analogue, calix[4]arene tetramethylamide 1, self-assembles in the presence of HCl to generate solid-state structures with chloride-filled and water-filled channels. Structure-activity studies indicate that the hydrophobicity, amide substitution, and macrocyclic framework of the calixarene are essential for HCl binding and transport. Calix[4]arene tetrabutylamide 2 is a rare example of an anion-dependent, synthetic ion channel.
- Sidorov, Vladimir,Kotch, Frank W.,Abdrakhmanova, Galya,Mizani, Robert,Fettinger, James C.,Davis, Jeffery T.
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- Efficient procedure for the preparation of amides using polymer-bound reagents
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An effective method for the conversion of acids into amides is presented. The two-step procedure includes the preparation of acid chloride intermediates using Pol-Ph3P and subsequent treatment of these intermediates with amines and polymer-bound base. The amides were accessible in high yields and purities without further purification.
- Buchstaller,Ebert,Anlauf
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p. 1001 - 1005
(2007/10/03)
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- Electrochemical generation and reactions of acyloxytriphenylphosphonium ions
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Constant-current electrolysis, in an undivided cell, of Ph3P in the presence of a carboxylic acid in CH2Cl2 containing 2,6-lutidinium perchlorate as the supporting electrolyte was shown to generate the corresponding acyloxyphosphonium ion, Ph3P+-OCOR, which was converted in situ to esters, amides, and β-lactams under mild conditions.
- Ohmori, Hidenobu,Maeda, Hatsuo,Kikuoka, Masayuki,Maki, Toshihide,Masui, Masaichiro
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p. 767 - 776
(2007/10/02)
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