AbstractThe title compound was preparedviaa malonic ester synthesis starting with α‐chloromethylpyrazine [2], and ending, after an asymmetric enzymatic hydrolysis of the racemicN‐acetyl‐β‐2‐pyrazinylalanine to theL‐form of the new amino acid. The optical purity was ascertained by1H‐NMR analysis at 360 MHz of the diastereoisomeric dipeptidesL‐pyrazinylalanine‐L‐leucine andD‐pyrazinylalanine‐L‐leucine. Hydrophobic, steric and electronic parameters for its side chain were also estimated, which can be useful for the quantitative study of structure‐activity relationships of biologically active peptide derivatives. The new amino acid could be introduced in the place of phenylalanine in the enkephalin‐like pentapeptide [D‐alanyl2, leucine5]enkephalin, thus showing good stability towards the class