Racemization in peptide synthesis. A laboratory experiment for senior undergraduates.

A laboratory experiment involving the coupling of N-benzoylamino acids with methyl N epsilon-benzyloxycarbonyl-L-lysinate using various methods is described. The extents of racemization are determined by analysis for the protected diastereomeric dipeptide ester products by quantitation of the separated ester methyl proton peaks of their nuclear magnetic resonance (60 MHz) spectra. Synthesis of the starting materials and additional exercises are included as options.