21456-46-2Relevant academic research and scientific papers
Diazotization of S-Sulfonyl-cysteines
Mear, Sarah Jane,Jamison, Timothy F.
, p. 15001 - 15007 (2019)
We report the preparation of enantiomerically enriched β-thio-α-hydroxy and α-chloro carboxylic acid and ester building blocks by diazotization of S-sulfonyl-cysteines. The thiosulfonate protecting group demonstrated resistance to oxidation and attenuation of sulfur's nucleophilicity by the anomeric effect. The key transformation was optimized by a 22 factorial design of experiment, highlighting the unique reactivity of cysteine derivatives in comparison with aliphatic amino acids.
Reactivite du nitrite de sodium. V. Action sur les amino-acides, peptides et proteines
Gouesnard, Jean-Paul
, p. 88 - 94 (2007/10/02)
The action of sodium nitrite on various amino-acids was re-examined in conditions approximating to a biological medium. 13C-NMR provides evidence of the existence of intramolecular ring closures and the formation of 5-membered rings with ornithine, citrulline and arginine.The reaction of cystine shows the opening of the sulphur bridges, whereas cysteine leads to the formation of carboxy-thiiran and 3-sulpho-lactic acid.The hydrolysis of the amide bonds of asparagine and glutamine is complete whereas the peptides studied - carnosine and aspartam - do not undergo hydrolysis of the peptide linkage.However, the first deamination of glutathion (γ-Glu-Cys-Gly) induces the peptide link to be broken and a cyclization with the formation of lactone to occur.A second deamination takes place on the cysteinyl residue released and allows the formation of a thiiran by intramolecular cyclization with the thiol group.The formation of thiiran was also observed with oxidized glutathion which has an S-S bridge.Finally, the formation of nitrosamines was detected by 15N-NMR during the reaction of sodium nitrite with two commercial products available to the general public.
