50299-14-4Relevant articles and documents
Synthesis of L-α-amino-ω-bromoalkanoic acid for side chain modification
Watanabe, Louis A.,Jose, Binoy,Kato, Tamaki,Nishino, Norikazu,Yoshida, Minoru
, p. 491 - 494 (2004)
L-α-Amino-ω-bromoalkanoic acids with side chain lengths varying from 4 to 10 methylene units have been conveniently synthesized as useful intermediates for the synthesis of functionalized non-natural amino acids.
Epoxy amino acids produced from allylglycines intramolecularly cyclised to yield four stereoisomers of 4-hydroxyproline derivatives
Krishnamurthy, Suvratha,Arai, Toru,Nakanishi, Kanae,Nishino, Norikazu
, p. 2482 - 2490 (2014/01/06)
Derivatives of 2-amino-4-pentenoic acid (allylglycine) were efficiently resolved using Subtilisin or acylase. The side-chain unsaturated bond of the enantiomerically pure amino acid with tert-butoxycarbonyl (Boc) protection was smoothly epoxidized with m-chloroperbenzoic acid. When the Boc protection of the amino group was removed, the amino group intramolecularly attacked the side-chain epoxide, generating compounds with five-membered rings: the 4-hydroxyproline derivatives. Two diastereomeric products were formed through the cyclisation reaction, for example, (2S,4S)-4-hydroxyproline benzyl ester (cis-8) and (2S,4R)-4-hydroxyproline benzyl ester (trans-8) were formed from (2S)-amino acid with a side-chain epoxide. Compound (2S,4S)-4-hydroxyproline benzyl ester (cis-8) was transformed to a lactone (cis-hydroxyproline lactone, 10) with the removal of benzyl alcohol. The cis-conformation was essential for the intramolecular ester exchange reaction; in fact, no lactone formation was observed for the trans isomer (trans-8). The separation of cis-hydroxyproline lactone and the trans-isomeric hydroxyproline benzyl ester was facile and clear, in contrast to the difficult separation of cis- and trans-hydroxyproline derivatives. Thus, two diastereomers of hydroxyproline derivatives for l-hydroxyproline and also for d-hydroxyproline were obtained, i.e., four diastereomers of hydroxyproline derivatives.
Chemoenzymatic synthesis of the four diastereoisomers of 4-hydroxypipecolic acid from N-acetyl-(R,S)-allylglycine: Chiral scaffolds for drug discovery
Lloyd, Richard C.,Smith, Mark E. B.,Brick, Dean,Taylor, Stephen J. C.,Chaplin, David A.,McCague, Raymond
, p. 762 - 766 (2013/09/06)
All four diastereoisomers of 4-hydroxypipecolic acid were prepared in a form conveniently protected for drug discovery applications with the use of industrially scaleable methodology. Resolution of the racemic starting material using proprietary acylases followed by an acyliminium ion cyclisation gave diastereomeric mixtures of 4-formyloxypipecolic acid, which were differentiated using an enzyme-catalysed hydrolysis. The products were separated by partition, and by following a sequence of straightforward chemical steps, the individual stereoisomers of the protected 4-hydroxypipecolates were crystallized to optical purity in 100 g quantities.