DEA treatment of an Fmoc protected peptide in solution caused degradation of the material as detected by analytical HPLC...has anybody any clue about what could be ever going on?
Any secondary amine will cleave Fmoc-group to a certain degree, depending on R2NH concentration and nucleophilicity. The primary cleavage by-product, dibenzfulvene (DBF), is quantitatively scavenged by nucleophilic amines like piperidine to give soluble 9-fluorenylmethylpiperidine. In case of a more hindered Et2NH, DBF forms mainly white insoluble polymer.