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seen framstella aspirin - 3 - amino - 2 - hydroxibutyrylaminoettiksyror and even new intermediate products derfor and seen to framstella these
seen framstella aspirin - 3 - amino - 2 - hydroxibutyrylaminoettiksyror and even new intermediate products derfor and seen to framstella these
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: IMAGE (I) wherein R1 represents a naphthyl or a group of the formula: IMAGE in which R6 and R7 represent individually hydrogen, halogen, amino or a protected amino, hydroxy or a protected hydroxy, a lower alkoxy or a lower alkyl and R2 represents a protected amino, with a starting compound represented by the general formula: IMAGE (II) wherein R3 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: IMAGE (III) wherein R1, R2 and R3 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: IMAGE (IV) wherein R1, R2 and R3 have the same meanings as above, and further converting the above compound into 3-amino-2-hydroxybutanoic acid represented by the general formula: IMAGE (V) wherein R2' 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: IMAGE (VI) wherein R4 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: IMAGE (VII) wherein R1 and R4 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.
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