Process for producing threo-3-amino-2-hydroxy-butanoyl-aminoacetic acids

Abstract

A process for producing threo-3-amino-2-hydroxybutanoylaminoacetic acids comprises the steps of allowing to react a starting compound represented by the general formula: ##STR1## wherein R.sub.1 represents a naphthyl or a group of the formula: ##STR2## in which R.sub.6 and R.sub.7 represent individually hydrogen, halogen, amino or a protected amino, hydroxy or a protected hydroxy, a lower alkoxy or a lower alkyl and R.sub.2 represents a protected amino, with a starting compound represented by the general formula: ##STR3## wherein R.sub.3 represents hydrogen or an ester residue, to obtain threo-3-protected amino-2-hydroxy-4-oxobutanoic acid or its ester represented by the general formula: ##STR4## wherein R.sub.1, R.sub.2 and R.sub.3 have the same meanings as above, and then reducing the same into threo-3-protected amino-2-hydroxybutanoic acid or its ester represented by the general formula: ##STR5## wherein R.sub.1, R.sub.2 and R.sub.3 have the same meanings as above, and further converting the above compound into 3-amino-2-hydroxybutanoic acid represented by the general formula: ##STR6## wherein R.sub.2 ' represents amino or a protected amino, thereafter condensing the same, in a conventional manner for forming a peptide coupling, with a compound represented by the general formula: ##STR7## wherein R.sub.4 represents an alkyl having 3-4 carbon atom or 3-guanidinopropyl, while previously protecting as required those groups not relevant to the reaction, and removing the protecting groups for the functional groups to produce threo-3-amino-2-hydroxybutanoylaminoacetic acids represented by the general formula: ##STR8## wherein R.sub.1 and R.sub.4 have the same meanings as above. This invention also provides the compounds represented by the general formula (III) as novel intermediates for the above aimed compounds and a process for producing the intermediates.