186832-71-3

Upstream product

• 188660-18-6 4-((S)-1-Benzyloxy-ethyl)-2-methyl-4H-oxazol-5-one 
• 188660-15-3 N-acetyl-O-benzyl-D-threonine benzyl ester 

Downstream Products

• 128609-40-5 O-benzyl-N-(tert-butoxycarbonyl)-L-allothreonine 
• 186826-30-2 (2S,3S)-2-Amino-3-benzyloxy-butyric acid 
• 188660-18-6 4-((S)-1-Benzyloxy-ethyl)-2-methyl-4H-oxazol-5-one 

Relevant academic research and scientific papers

Synthetic studies on threonines. The preparation of protected derivatives of D-allo- and L-allo-threonine for peptide synthesis

N-Acetylated threonine derivatives, having tert-butyl or benzyl-based side-chain protection, form isolable 5(4H)-oxazalones on treatment with N-ethyl-N'-3-dimethylaminopropyl carbodiimide. N-chloroacetylated threonine derivatives, on the other hand, do not form oxazolones so readily. The N-acetylated oxazolones an easily epimerized and lead to diastereoisomeric mixtures of threonine derivatives on hydrolysis with dilute aqueous acid. The components of these mixtures can be separated chromatogaphically, but a useful alternative for the O-benzylated mixture is selective enzymatic hydrolysis using hog kidney acylase. These chemical transformations provide the basis for practical syntheses of protected derivatives of the non-proteinogenic allo-threonines, suitable for use in peptide synthesis.

Simple methods for the preparation of protected derivatives of D-allo- and L-allo-threonine

Practical syntheses of protected derivatives of the non-proteinogenic allo-threonines are described. The key step is enzymatic resolution of threonine diastereomers, produced on controlled epimerization of the α-carbon atom. The protected allo-threonines are obtained in good overall yield and can be used in standard peptide synthesis protocols.