Nebenreaktionen bei Peptidsynthesen, V. O-Sulfonierung von Serin und Threonin während der Abspaltung der Pmc- und Mtr-Schutzgruppen von Argininresten bei Fmoc-Festphasen-Synthesen.

: A novel side reaction in Fmoc-solid-phase synthesis, which occurs during removal of protecting groups and detachment from the resin, was elucidated by investigations on model peptides: During the cleavage of Pmc- or Mtr-protecting groups from arginine residues by trifluoroacetic acid in peptides with O-tert-butyl-protected aliphatic hydroxyamino acids, peptides containing O3-sulfo-serine and O3-sulfo-threonine are formed as side-products in high yields, if suitable scavengers are absent. Subsequent to their isolation and purification, the structures of these peptide sulfuric acid mono-esters could unequivocally be proven by chemical and spectroscopic (MS, NMR, IR) methods.