On Cysteine and Cystine Peptides. I. New S-Protecting Groups for Cysteine

Mercury binding by ferrocenoyl peptides with sulfur-containing side chains: Electrochemical, spectroscopic and structural studies

“…Ferrocene-1,1 0 -dicarboxylic acid was synthesised following the literature procedure [46], as were S-methyl-L-cysteine (from L-cysteine using sodium metal and methyl iodide in absolute ethanol [47], S-benzyl-L-cysteine (from L-cysteine and benzyl bromide) [48], S-benzhydryl-L-cysteine (from L-cysteine and diphenylmethanol in trifluoroacetic acid (TFA)) [49], S-trityl-L-cysteine and S-trityl-DL-homocysteine (from the free amino acid and triphenylmethanol in TFA) [50]. S-Protected amino acids were converted to their methyl esters in quantitative yield by reaction with thionyl chloride and methanol [51].…”

Synthetic Cystine-Knot Miniproteins – Valuable Scaffolds for Polypeptide Engineering

“…From the vast repertoire of cysteine side-chain protection groups, trityl, acetamidomethyl, S-tert.-butyl, and tert.-butyl are typical orthogonal combinations [157][158][159]. To date, a number of cystine-knot peptides was synthesized following the strategy of regioselective disulfide formation [160,161].…”

Trends to Acid-Labile Cys Protecting Groups: Thp as an Efficient and Non-Aromatic Cys Protecting Group for Fmoc Chemistry

“…Therefore, the selective protecting group elimination is possible, depending on the acidic conditions used. As a result of years of studies in the field, there are several Cys protecting groups available; some of them are labile in low acid concentration such as Mmt [8], Trt [9][10][11] or Thp [12,13]; others are more stable in low concentrations of trifluoroacetic acid (TFA) but cleavable using higher quantity of TFA -Diphenylmethyl (Dpm) [9,11,14], tBu [15,16] or MBom [17] and moreover, there are groups which are completely stable to TFA and removable using harsh conditions such as HF, for example Bom [18], Meb or Mob [19][20][21] groups.…”