In the crystal of the title compound, C(8)H(9)NO(2)S, synthesized by the oxidation of 2-(methyl-sulfan-yl)benzamide using NaOCl with 2,2,6,6-tetra-methyl-piperidyl-1-oxy (TEMPO) as the catalyst, mol-ecules are linked via inter-molecular N-H⋯O(amide) hydrogen bonds, forming centrosymmetric amide-amide dimers which are extended into a two-dimensional lamellar framework parallel to (100) through a...

Model reactions offer a chemical mechanism by which formation of a sulfenyl amide residue at the active site of the redox-regulated protein tyrosine phosphatase PTP1B protects the cysteine redox switch in this enzyme against irreversible oxidative destruction. The results suggest that 'overoxidation' of the sulfenyl amide redox switch to the sulfinyl amide in proteins is a chemically reversible...

Amide-amide hydrogen bonds have been implicated in directing protein folding and enhancing protein stability. Inversion transfer (13)C NMR spectroscopy and IR spectroscopy were used to compare the ability of various amide solvents and of water to alter the rate of the cis-trans isomerization of the prolyl peptide bond of Ac-Gly-[β,δ-(13)C]Pro-OMe and the amide I vibrational mode of [(13)C=O]Ac-...

Sucrose phosphorylase catalysed glycosylation of glyceric acid amide with complete regio- and diastereo-selectivity is studied. (R)-2-O-α-D-Glucopyranosyl glyceric acid amide was obtained in high yield from single-step transformation of racemic glyceric acid amide and sucrose. Non-productive binding of (S)-glyceric acid amide appeared to underlie strict enantiodiscrimination by the enzyme, thus...

A. S. Shawali, M. A . A bdallah , and M. E. M. Z ay ed Department of Chemistry, Faculty of Science, University of Cairo, Giza, Egypt Reprint requests to Dr. A. S. Shawali. E-mail: [email protected] Z. Naturforsch. 55b, 546-552 (2000); received February 4. 2000 Ring-Chain Tautomerism. Heterocyclic Ring Transformation, 1,3,4-Thiadiazoles The synthesis and antimicrobial activity of a s...

2,6-Bis(2-quinolyl)-4(1H)-pyridone 1, a novel quinoline analogue of the well-known ligand 2-terpyridone, shows unusual fluorescence with a large Stokes shift and low energy emission. Pyridine-pyridone tautomerism is investigated by NMR and theoretical methods and indicates that the low energy emission is from the pyridine form. 1 reacts with Ag(i) salts to give a double helical Ag2N6 core showi...

In this laboratory exercise we will measure a chemical equilibrium constant using key proton signals in a Nuclear Magnetic Resonance (NMR) spectrum. Those doing the “traditional” P Chem experiments will examine a keto-enol tautomerism, while those doing the “biophysical” experiments will look at the cis-trans equilibrium for a peptide bond. In each case, the relative concentration of the equili...