| abstract |
A method for recovering an optically pure amino acid derivative from a waste liquor collected after a coupling reaction in peptide synthesis, comprising the steps of (a) adding into the waste liquor, in which an uncoupled amino acid derivative or an uncoupled small peptide fragment is contained, a compound selected from the group consisting of 1-hydroxybenzotriazole (HOBt), 1-hydroxy-7-azabenzotriazole (HOAt), 3-hydroxy-4-oxo-3,4-dihydro-1,2,3-benzotriazine (HOObt) and N-hydroxy-5-norbornen-2,3-dicarboxylic acid imide(HONB); (b) concentrating the waste liquor obtained in step (a); (c) treating a residue obtained in step (b) with an acidic buffer solution containing a tertiary amine; and (d) extracting and purifying the uncoupled amino acid derivative or the uncoupled small peptide fragment under acidic conditions. |