1117-77-7Relevant articles and documents
Hydrogen bonding of 1-cyclohexyluracil with acetylglycine N-methylamide
Carmona, P.,Garcia-Ramos, J. V.
, p. 155 - 158 (1984)
I.r. spectroscopy was used to determine the enthalpy of hydrogen bond complex formation of 1-cyclohexyluracil with acetylglycine N-methylamide, in chloroform solution.Enthalpy of association is found to be -5.4 Kcal/mole for the dimer of acetylglycine N-methylamide and -4.7 Kcal/mole for the mixed dimers of this dipeptide with 1-cyclohexyluracil.These thermodynamic parameters and the i.r. spectra of the solutions suggest that the structures of these dimers are cyclic.
Oxidative Damage in Aliphatic Amino Acids and Di- and Tripeptides by the Environmental Free Radical Oxidant NO3?: the Role of the Amide Bond Revealed by Kinetic and Computational Studies
Nathanael, Joses G.,Wille, Uta
, p. 3405 - 3418 (2019)
Kinetic and computational data reveal a complex behavior of the important environmental free radical oxidant NO3? in its reactions with aliphatic amino acids and di- and tripeptides, suggesting that attack at the amide N-H bond in the peptide backbone is a highly viable pathway, which proceeds through a proton-coupled electron transfer (PCET) mechanism with a rate coefficient of about 1 × 106 M-1 s-1 in acetonitrile. Similar rate coefficients were determined for hydrogen abstraction from the α-carbon and from tertiary C-H bonds in the side chain. The obtained rate coefficients for the reaction of NO3? with aliphatic di- and tripeptides suggest that attack occurs at all of these sites in each individual amino acid residue, which makes aliphatic peptide sequences highly vulnerable to NO3?-induced oxidative damage. No evidence for amide neighboring group effects, which have previously been found to facilitate radical-induced side-chain damage in phenylalanine, was found for the reaction of NO3? with side chains in aliphatic peptides.
Conformational Analysis of Linear Peptides. 3. Temperature Dependence of NH Chemical Shifts in Chloroform
Stevens, E. S.,Sugawara, N.,Bonora, G. M.,Toniolo, C.
, p. 7048 - 7050 (1980)
The following conclusions concerning NH chemical shifts for peptides in chloroform are based on numerous observations on small model peptides reported here and also on data in the literature. (1) The temperature dependence of chemical chift for an amide NH proton exposed to solvent in chloroform solutions is 0.0024 +/- 0.0005 ppm K-1. (2) Small temperature dependencies can also be observed if the NH group is shielded from solvent and remains shielded over the temperature range of the 1H NMR measurements. (3) Larger temperature dependencies are observed if the NH group is shielded from solvent initially but becomes exposed with increasing temperature, a situation which holds when intermolecular self-association is significant or when intermolecularly hydrogen-bonded conformations unfold as the temperature is increased.Previously proposed conformations based on the presumption that NH chemical shifts display in chloroform solution the same behavior as in strongly polar solvents are herein reexamined.
Methyl 2-(Bromomethyl)acrylate, Methyl Acrylate, and Glycine in the Synthesis of Functionalized Pyrrolidones
Selezneva,Valiullina,Galeeva,Spirikhin,Miftakhov
, p. 1665 - 1669 (2018)
Possible application of methyl 2-(bromomethyl)acrylate, methyl acrylate, and glycine in the synthesis of functionalized pyrrolidones was considered.
1,1'-OXALYLDIIMIDAZOLE, A NEW REAGENT FOR ACTIVATION OF CARBOXYLIC ACID
Murata, Shizuaki
, p. 1819 - 1820 (1983)
Carboxylic acids and their salts are converted into the 1-acylimidazoles by the title reagent.This reaction is applied for esterification of fatty acids.
Chemoselectivity in coupling of azides with thioacids in solution-phase and solvent-free conditions
Nagarajan, Sangaraiah,Shanmugavelan, Poovan,Sathishkumar, Murugan,Priyadharshini, Namachivayam,Sudakar, Padmanaban,Ponnuswamy, Alagusundaram
, p. 668 - 680 (2013/01/15)
Solvent-free rapid coupling of monothiocarboxylic acid with azide affords carboxamide chemoselectively. Triphenyl phosphine included as an additive influences the chemoselectivity, yielding carboxamide and thioamide. Similar variation in the chemoselectivity is observed in the absence and presence of triphenyl phosphine in solution-phase methodology. Rapidity and ecofriendliness of the solvent-free approach to yield the products in just 15min is noteworthy compared to the solution-phase protocol, which has a long reaction time (1-3 days).