Abstract: Five kinds of racemic ring-modified phenylalanines were synthesized by using aniline derivatives as the raw materials and further characterized with routine analysis. Most of the amino acids were resolved with chymotrypsin or subtilisin and some protected forms of the amino acids were obtained. The possible mechanism of the method for the relatively large scale synthesis was discussed. These unusual amino acids were used as the building blocks for peptide based antagonists. It had latent investigation values that the physicochemical properties and metabolism behavior in vivo of the peptide containing the amino acids were changed.

Key words: Chymotrypsin, Subtilisin, Diazotization, Resolution, Unnatural amino acids, HPLC