Rapid, one-pot synthesis of urethane-protected tripeptides
作者:Yun-Fei Zhu、William D. Fuller
DOI:10.1016/0040-4039(94)02391-n
日期:1995.2
Urethane-protected tripeptides are synthesized in solution, without isolation or purification of intermediates, using urethane-protected N-carboxyanhydrides as coupling reagents and hydrogenation for removal of N-protection.
A micro-flow rapid dual activation approach for urethane-protected α-amino acid <i>N</i>-carboxyanhydride synthesis
作者:Ren Okabe、Naoto Sugisawa、Shinichiro Fuse
DOI:10.1039/d2ob00167e
日期:——
the rapid dual activation (10 s, 20 °C) of a combination of an α-aminoacidN-carboxyanhydride and alkyl chloroformate in the synthesis of a urethane-protected α-aminoacidN-carboxyanhydride in a micro-flow reactor. The key to success was the combined use of two amines that activated both substrates with proper timing. Three amines, i-Pr2NEt, Me2NBn, or N-ethylmorpholine, were used with pyridine in
Method for purifying an amino acid-n-carboxy anhydride
申请人:SHIN-ETSU CHEMICAL CO., LTD.
公开号:US10975042B2
公开(公告)日:2021-04-13
The present invention is a method for purifying an NCA, including the steps of: a) dissolving an NCA contaminated with impurities into a solvent which is a good solvent and is not a chlorinated solvent followed by stirring to precipitate an undissolved impurity to afford a suspension, b) adding an acidic filter aid having ability to trap a basic impurity to the obtained suspension followed by filtration and/or forming a fixed bed of the acidic filter aid having ability to trap a basic impurity followed by filtering the suspension to bring the suspension to be in contact with the acidic filter aid having ability to trap a basic impurity, and c) adding the obtained filtrate dropwise to a poor solvent for NCA to crystallize out the NCA in which the impurities are removed. This makes it possible to purify a low-purity NCA conveniently to afford a high-purity NCA.
METHOD FOR PURIFYING AN AMINO ACID-N-CARBOXY ANHYDRIDE
申请人:Shin-Etsu Chemical Co., Ltd.
公开号:EP3572408B1
公开(公告)日:2021-10-27
Activation of N,N-bis(alkoxycarbonyl) amino acids. Synthesis of N-alkoxycarbonyl amino acid N-carboxyanhydrides and N,N-dialkoxycarbonyl amino acid fluorides, and the behavior of these amino acid derivatives.
Series of Boc- and Cbz-NCAs (2), and of N,N-bis(alkoxycarbonyl) amino acid fluorides U2AAFs (3) have been prepared by activation of N,N-bis-Boc- and N-Cbz,N-Boc-α-amino acids (1) with the Vilsmeier reagent or cyanuric fluoride. The absence of epimerization of 2 and 3 during both their formation and their coupling under standard conditions of peptide synthesis had been demonstrated by optical purity