997-55-7Relevant articles and documents
Synthetic strategy of new powerful tris-bisphosphonic ligands for chelation of uranyl, iron, and cobalt cations
Burgada, Ramon,Bailly, Théodorine,Prangé, Thierry,Lecouvey, Marc
, p. 2315 - 2319 (2007)
New tripodal uranyl ion chelators containing gem-bisphosphonic units have been synthesized. All bisphosphonic units present a side chain with 0, 1, or 2 methylene group terminated by -NH2 or -CO2H group. These units were respectively coupled with a -CO2H or -NH2 functions of a suitable tri-functional platform. The shape and size of the new designed ligands were selected and validated through computer molecular modelization.
Reactions of substituted aspirins with amino acids
Orth, Elisa S.,Medeiros, Michelle,Souza, Bruno S.,Caon, Natalia B.,Kirby, Anthony J.,Nome, Faruk
supporting information, p. 939 - 945 (2014/01/06)
Acyl transfers are key reactions in biology and in the laboratory. In biological systems they are involved in energy transport, in the assembly of complex molecules and in the mechanisms of efficient action of many hydrolytic enzymes. We report a mechanistic and calculational study of the selective N-acylation reactions of amino acids by substituted aspirins, under mild conditions, in water at 25 °C. The acetylated amino-acid products of the reactions were identified by nuclear magnetic resonance, and the reaction steps were studied by density functional theory. Copyright
Peculiar stability of amino acids and peptides from a radical perspective
Watts, Zachary I.,Easton, Christopher J.
supporting information; experimental part, p. 11323 - 11325 (2011/03/19)
(Chemical Equation Presented) Photochemical reactions of free and N-acetyl α-amino acids with chlorine and deuterium labeled hydrogen peroxide have been used to determine both the relative rates of reaction of molecules of these classes and the relative reactivity of their different types of hydrogen toward abstraction by chlorine and oxygen centered radicals. The relative rates of reaction of these species range over more than 3 orders of magnitude; however, where data are available from more than one amino acid for a particular type of group at a specific position on the side chain, the values are remarkably similar. The predictive utility of these results has been demonstrated for the regioselective chlorination of tripeptides. More generally this analysis shows that the backbone and adjacent side chain positions of amino acids and peptides are peculiarly resistant to hydrogen atom transfer, and a similar pattern of reactivity has been noted from earlier studies of reactions of modified substrates catalyzed by isopenicillin-N-synthetase. Such resistance stands out in contrast to the common occurrence of free radical reactions of α-amino acids, peptides, and proteins and their importance in biology. Nevertheless, it provides a reason for the ability of amino acids and their derivatives to avoid degradation in Nature where they are constantly exposed to radicals, and it accounts, at least in part, for the anomalous ability of enzymes to catalyze free radical reactions without being broken down by the radical intermediates.
