Acid-Labile Cys-Protecting Groups for the Fmoc/tBu Strategy: Filling the Gap

Abstract

To address the existing gap in the current set of acid-labile Cys-protecting groups for the Fmoc/tBu strategy, diverse Fmoc-Cys(PG)-OH derivatives were prepared and incorporated into a model tripeptide to study their stability against TFA. S-Dpm proved to be compatible with the commonly used S-Trt group and was applied for the regioselecive construction of disulfide bonds.

On the Mechanism of Phenolic Formylation Mediated by TiCl4 Complexes: Existence of Diradical Intermediates Induced by Valence Tautomerism

“…These derivatives can be readily accessed by formylation of phenols by using the TiCl 4 / phenol and/or diethyl ether lead to different stable diradical intermediates induced by valence tautomerism that provide valuable activated reagents. [4,5] The most interesting feature of this synthetic methodology deals with the regioselectivity of formylation towards the ortho-position to the hydroxy phenolic group, that is more specific than in other formylation protocols. Cl 2 CHOCH 3 system, [1,2] which has proved to be of considerable synthetic potential.…”

Synthesis of PAF, an Antifungal Protein from P. chrysogenum, by Native Chemical Ligation: Native Disulfide Pattern and Fold Obtained upon Oxidative Refolding

“…The chemical synthesis peptides containing multiple disulfides in a regioselective manner is still a challenging task for peptide chemists, although recently many improvements were described in the literature 9. 10 The strategies involve either directed oxidative folding from polythiol precursors or stepwise introduction of the desired disulfide bonds using orthogonal protecting groups for the cysteine thiols 11. 12 Both strategies can be carried out in the liquid phase or, rarely, on solid phase 13.…”

Disulfide Formation Strategies in Peptide Synthesis

“…[49] We were searching for a replacement for the Mob group that is stable to low concentrations of TFA but readily removable with 95 % TFA. [49] We were searching for a replacement for the Mob group that is stable to low concentrations of TFA but readily removable with 95 % TFA.…”

“…Diphenylmethyl (Dpm, 3), 4-methoxy-2-methylbenzyl (4MeO-2MeBn, 4), 2,6-dimethoxybenzyl (2,6diMeOBn, 5), and 4,4Ј-dimethoxydiphenylmethyl (Ddm, 6) have recently been introduced by our group as acid-labile Cys protecting groups. [49] We were searching for a replacement for the Mob group that is stable to low concentrations of TFA but readily removable with 95 % TFA. The protecting groups Dpm, 4MeO-2MeBn, and 2,6diMeOBn were found to be appropriate for this purpose.…”