Chemical Ligation of S-Scylated Cysteine Peptides to Form Native Peptides via 5-, 11-, and 14-Membered Cyclic Transition States
作者:Alan R. Katritzky、Srinivasa R. Tala、Nader E. Abo-Dya、Tarek S. Ibrahim、Said A. El-Feky、Kapil Gyanda、Keyur M. Pandya
DOI:10.1021/jo1015757
日期:2011.1.7
5-membered cyclictransitionstates. Microwave irradiation of S-(Pg-α-aminoacyl)tripeptide 15 and S-(Pg-α-aminoacyl)tetrapeptide 17 in the presence of NaH2PO4/Na2HPO4 buffer solution at pH 7.8 achieved chemical ligations, involving intramolecular migrations of acyl groups, via 11- and 14-membered cyclictransitionstates from the S-atom of a cysteine residue to a peptide terminal amino group to form native
Benzotriazole-Mediated Syntheses of Depsipeptides and Oligoesters
作者:Ilker Avan、Srinivasa R. Tala、Peter J. Steel、Alan R. Katritzky
DOI:10.1021/jo200174j
日期:2011.6.17
Reactions of O-Pg(α-hydroxyacyl)benzotriazoles with (a) unprotected α-hydroxycarboxylic acids, (b) amino acids, and (c) amines afforded, respectively, chirally pure (a) oligoesters, (b) depsidipeptides, and (c) amide conjugates (yields 52−94%). N-Pg(α-Aminoacyl)benzotriazoles reacted with α-hydroxycarboxylic acids to yield depsidipeptides (47−87%). N-Pg(depsidipeptidoyl)benzotriazoles, obtained from
The chemical ligation of selectively S-acylated cysteine peptides to form native peptides via 5-, 11- and 14-membered cyclic transition states
作者:Alan R. Katritzky、Nader E. Abo-Dya、Srinivasa R. Tala、Zakaria K. Abdel-Samii
DOI:10.1039/c003234d
日期:——
S-acyl-isopenta-peptides undergo chemicalligation; migration of the cysteine S-acyl groups to the N-terminal amino acids via 5-, 11-, and 14-membered transitionstates giving the corresponding native di-, tetra-, and penta-peptides. By contrast, the S-acyl-isotripeptide prefers intermolecular acylation from one molecule to another over an 8-membered intramolecular transition state. The developed methodology
A benzotriazole-mediated route to protected marine-derived hetero-2,5-diketopiperazines containing proline
作者:Olivier Nsengiyumva、Sadra Hamedzadeh、James McDaniel、Jocelyn Macho、Grant Simpson、Siva S. Panda、Khanh Ha、Iryna Lebedyeva、Hassan M. Faidallah、Manal Metgen AL-Mohammadi、C. Dennis Hall、Alan R. Katritzky
DOI:10.1039/c5ob00023h
日期:——
Dipeptidoyl benzotriazolides containing proline were cyclized by triethylamine into 2,5-diketopiperazines.
含脯氨酸的二肽苯并三唑酰胺被三乙胺环化成2,5-二酮哌嗪。
DBU-Catalyzed transprotection of N-Fmoc-cysteine di- and tripeptides into S-Fm-cysteine di- and tripeptides
作者:Alan R. Katritzky、Nader E. Abo-Dya、Abdelmotaal Abdelmajeid、Srinivasa R. Tala、M. S. Amine、Said A. El-Feky
DOI:10.1039/c0ob00663g
日期:——
The transprotection of N-Fmoc-cysteine containing di- and tripeptides possessing a free SH group to produce the corresponding S-Fm-cysteine di- and tripeptides bearing a free amino group is accomplished efficiently with DBU in dry THF. The N-Fmoc to S-Fm transformation mechanism is discussed. S-Fm-Cysteine di- and tripeptides readily form amide bonds on coupling with N-(Pg-α-aminoacyl)benzotriazoles and N-(Pg-α-dipeptidoyl)benzotriazoles to give larger peptides.