136083-72-2Relevant articles and documents
Scope and limitations of pseudoprolines as individual amino acids in peptide synthesis
Senko, Dmitry A.,Timofeev, Nikita D.,Kasheverov, Igor E.,Ivanov, Igor A.
, p. 665 - 671 (2021/04/09)
Protected 4-carboxyoxazolidines and thiazolidines (pseudoprolines) are derivatives of serine, threonine or cysteine amino acids. Such compounds are used in peptide synthesis among the other protected amino acids. They are usually practiced when a peptide sequence is readily aggregating during synthesis due to their ability to disrupt secondary structure formation. Such compounds are usually applied as dipeptides. In present work Fmoc-protected pseudoprolines were synthesized and applied in peptide synthesis not as dipeptides but as individual amino acids. Different acylation protocols and amino acids were tested to acylate pseudoprolines. Several “difficult” peptides were synthesized to confirm the efficacy of such constructions. It was shown that pseudoprolines could be easily synthesized and used in automated or manual synthesis not as dipeptides but as ordinary amino acids.
Determination of Chemical and Enantiomeric Purity of α-Amino Acids and their Methyl Esters as N-Fluorenylmethoxycarbonyl Derivatives Using Amylose-derived Chiral Stationary Phases
Islam, Md. Fokhrul,Adhikari, Suraj,Paik, Man-Jeong,Lee, Wonjae
, p. 332 - 338 (2019/04/13)
Liquid chromatographic enantiomer separation and simultaneous determination of chemical and enantiomeric purity of α-amino acids and their methyl esters as N-fluorenylmethoxycarbonyl (FMOC) derivatives was performed on three covalently bonded type chiral stationary phases (CSPs) derived from amylose derivatives. The enantiomer separation of α-amino acid esters as N-FMOC derivatives was better than that of the corresponding acids, especially for CSP 1 and 2. Chemical impurities as the corresponding racemic acids present in several commercially available racemic amino acid methyl esters were observed to be 0.49–17.50%. Enantiomeric impurities of several commercially available L-amino acid methyl esters were found to be 0.03–0.58%, whereas chemical impurities as the corresponding racemic acids present in the same analytes were found to be 0.13–13.62%. This developed analytical method will be useful for the determination of chemical and enantiomeric purity of α-amino acids and/or esters as N-FMOC derivatives using amylose-derived CSPs.
Synthesis of a chiral precursor for no-carrier-added (NCA) PET tracer 6- [18F]fluoro-L-dopa based on regio- and enantioselective alkylation of 2,4- bis(chloromethyl)-5-iodoanisole
Kuroda, Chiaki,Ochi, Atsushi,Nakane, Noritoshi,Umeyama, Takashi,Muto, Nobuko,Niimura, Nami,Teramoto, Yoshiki,Nogami, Hiroyuki,Reddy, Guvvala N.
, p. 417 - 422 (2007/10/03)
(2S,5S)-5-(3-Formyl-6-iodo-4-methoxybenzyl)-1-t-butoxycarbonyl-2-t- butyl-3-methyl-4-imidazolidinone (11), a chiral intermediate towards NCA PET tracer 6-[18F]fluoro-L-dopa (1), was synthesized from 3-iodoanisole in four steps. 3-Iodoanisole was first bischloromethylated to 2,4-bis(chloromethyl)- 5-iodoanisole (14). Regio- and enantio-selective alkylation of 14 with (S)-1- (t-butoxycarbonyl)-2-t-butyl-3-methyl-4-imidazolidinone (12) afforded 33, which was then hydrolyzed and oxidized to the desired intermediate 11.
