The epimerization of peptide aldehydes--a systematic study.

Peptide aldehydes are interesting targets as enzyme inhibitors, and can be used for pseudopeptide chemistry or ligation. However, they are known to be subjected to epimerization during synthesis or purification. By (1)H NMR, a model dipeptide aldehyde can be used to check the possible epimerization occurring during synthesis. Various purification methods were investigated, but none was free from epimerization.