167015-11-4Relevant articles and documents
Convergent Total Synthesis of the Siderophore Piscibactin as Its Ga3+Complex
De La Fuente, M. Carmen,Jiménez, Carlos,Rodríguez, Jaime,Segade, Yuri,Valderrama, Katherine
, p. 340 - 345 (2021/01/13)
The siderophore piscibactin is a key virulence factor involved in the iron uptake of pathogenic bacteria Photobacterium damselae subsp. piscicida and Vibrio anguillarum, responsible for the fish diseases photobacterioisis (pasteurellosis) and vibriosis, respectively. A convergent total synthesis of its Ga3+ complex using l-/d-cysteine as chiral agents and Meldrum's acid is described. A Staudinger reduction/Aza-Wittig process in the synthesis of the acid-sensitive β-hydroxy-2,4-disubstituted thiazoline moiety and the convenient protecting groups was a key step in this synthesis.
Investigation of Cysteine as an Activator of Side-Chain N→S Acyl Transfer and Tail-to-Side-Chain Cyclization
Castillo-Pazos, Durbis J.,Macmillan, Derek
, p. 1923 - 1928 (2017/09/13)
N→S Acyl transfer is a popular method for the postsynthesis production of peptide C α -thioesters for use in native chemical ligation and for the synthesis of head-to-tail cyclic peptides. Meanwhile thioester formation at the side chain of aspartic or glutamic acids, leading to tail-to-side-chain-cyclized species, is less common. Herein we explore the potential for cysteine to function as a latent thioester when appended to the side chain of glutamic acid. Initial insights gained through study of C-terminal β-alanine as a model for the increased chain length were ultimately applied to peptide macrocyclization. Our results emphasize the increased barrier to acyl transfer at the glutamic acid side chain and indicate how a slow reaction, facilitated by cysteine itself, may be accelerated by fine-tuning of the stereoelectronic environment..
Efficient procedure for the preparation of oligomer-free N-fmoc amino acids
Nowshuddin, Shaik,Rao,Reddy, A. Ram
experimental part, p. 2022 - 2031 (2009/11/30)
A two-step method is presented for the peptide-free, high-purity, and high-yield synthesis of N-Fmoc amino acids. The first step involves the preparation of stable dicyclohexylammonium-amino acid ionic adduct in acetone. Subsequently, the ionic adducts, on reaction with Fmoc-Nosu under mild alkaline conditions, give dipeptide-free N-Fmoc amino acids. The positive charge of the dicyclohexylammonium counterion in the ionic salt has a longer radius, moderating the nucleophilicity of the carboxylate ion of the amino acid and preventing by-products by arresting the formation of mixed anhydrides, the precursors of oligopeptide impurities.
