Peptide Bond Formation Mediated by 4,5-Dimethoxy-2-mercaptobenzylamine after Periodate Oxidation of the N-Terminal Serine Residue
作者:Toru Kawakami、Kenichi Akaji、Saburo Aimoto
DOI:10.1021/ol0157813
日期:2001.5.1
[reaction in text] A thiol linker-attached peptide was prepared from a nonprotected peptide via an N(alpha)()-alpha-oxoacyl peptide. Selective oxidation of the N-terminal serine with sodium periodate gave the N(alpha)-glyoxyloyl peptide, reductiveamination of which with 4,5-dimethoxy-2-(triphenylmethylthio)benzylamine gave an N(alpha)-4,5-dimethoxy-2-mercaptobenzyl glycyl peptide after removal of
Synthesis and application of an auxiliary group for chemical ligation at the X-gly site
作者:Jean Vizzavona、Fritz Dick、Thomas Vorherr
DOI:10.1016/s0960-894x(02)00319-0
日期:2002.8
into peptides to study the reaction with thiobenzyl-activated derivatives. The target peptides have been obtained by standard chemical ligation reaction, followed by TMSBr-assisted cleavage to remove the auxiliary group. Prior to Dmmb removal, under acidic conditions an unexpected rearrangement was observed and evidence for a mechanism is provided.
An N–S acyl shift reaction of thiol-containing peptides in a trifluoroacetic acid (TFA) solution was confirmed by a combination of 13C NMR spectroscopy, reversed-phase (RP) HPLC, and MS analyses. A model peptide containing a cysteine residue was transformed into an S-peptide in a TFA solution. The S-peptide was quickly transformed to the original peptide during RP-HPLC analysis even when an eluent that contained 0.1% TFA was used. A peptide that had an N-2-mercapto-4,5-dimethoxybenzyl (Dmmb) group was also transformed into an S-peptide, forming a thioester bond with the thiol of the Dmmb group by TFA treatment. The generated S-peptide was isolated by directly injecting the reaction mixture into a RP-HPLC and was readily converted to the corresponding 2-sulfoethyl thioester via an intermolecular thiol exchange reaction with sodium 2-mercaptoethanesulfonate. The 2-sulfoethyl peptide thioester is widely used as a building block in polypeptide synthesis. The N–S acyl shift reaction observed in peptides with or without an auxiliary group provides a new route for the preparation of peptide thioesters.