Synthesis of Four Diastereoisomers of Histopine

Article abstract of DOI:10.1246/bcsj.55.3870

Four isomers of histopine, N²-(1-carboxyethyl)histidine, were prepared to provide their physicochemical properties.A diastereomeric mixture, (RS),(S)-histopine (N²-<(RS)-1-carboxyethyl>-(S)-histidine), was synthesized from 2-oxopropionic acid and (S)-histidine by reduction with sodium cyanoborohydride.The mixture was separated into its components, (S),(S)-histopine and (R),(S)-histopine, by an ion-exchange column chromatography.In a similar manner, (R),(R)-histopine and (S),(R)-histopine were prepared.Configurations of the four isomers obtained were assumed from their ORD data by comparison with those of the isomers of octopine (N²-(1-carboxyethyl)arginine) with a definite configuration.