作者:Robert V. Kolakowski、Ning Shangguan、Ronald R. Sauers、Lawrence J. Williams
DOI:10.1021/ja057533y
日期:2006.5.1
A combined experimental and computational mechanistic study of amide formation from thioacids and azides is described. The data support two distinct mechanistic pathways dependent on the electronic character of the azide component. Relatively electron-rich azides undergo bimolecular coupling with thiocarboxylates via an anion-accelerated [3+2] cycloaddition to give a thiatriazoline. Highly electron-poor
two‐step strategy for thiopeptide bond formation with readily available monothiocarboxylic acids as thioacyl donors is described. The α‐thioacyloxyenamide intermediates formed from the ynamides and monothiocarboxylic acids can be purified, characterized, and stored. The balance between their activity and stability enables them to act as effective thioacylating reagents to afford thiopeptide bonds under mild
Chemoselective Synthesis of N-Terminal Cysteinyl Thioesters via β,γ-C,S Thiol-Michael Addition
作者:Rita Petracca、Katherine A. Bowen、Lauren McSweeney、Siobhan O’Flaherty、Vito Genna、Brendan Twamley、Marc Devocelle、Eoin M. Scanlan
DOI:10.1021/acs.orglett.9b01013
日期:2019.5.3
Dehydroalanine (ΔAla) is a highly electrophilic residue that can react efficiently with sulfur nucleophiles to furnish cysteinyl analogues. Herein, we report an efficient synthesis of N-terminal cysteinyl thioesters, suitable for S,N-acyl transfer, based on β,γ-C,S thiol-Michael addition. Both ionic and radical-based methodologies were found to be efficient for this process.
as novel thioacylating reagents in solidphasepeptidesynthesis. This method is amenable for 19 of 20 proteinogenic amino acids, His being the exception. One to multiple thioamide substitutions could be incorporated into a growing peptide with no epimerization or a low level of epimerization. By using this method, a fully thioamide-substituted hexapeptide containing up to five continuous thioamide
Thio Acid/Azide Amidation: An Improved Route to <i>N</i>-Acyl Sulfonamides
作者:Kristin N. Barlett、Robert V. Kolakowski、Sreenivas Katukojvala、Lawrence J. Williams
DOI:10.1021/ol052671d
日期:2006.3.2
A one-pot procedure for the conversion of carboxylic acids to N-acyl sulfonamides, via thio acid/azide amidation, is presented. The method is compatible with acid- and base-sensitive amino acid protection. N-Acyl sulfonamide synthesis on solid support, peptide thio acid/sulfonazide coupling, and N-alkylamide synthesis via selective cleavage of sulfonyl from an N-alkyl-N-acyl sulfonamide are also reported