title: [Side-reactions in peptide synthesis, III. Synthesis and characterization of Nin-tert-butylated tryptophan derivatives (author's transl)].
abstract: It was possible to elucidate a side reaction which had long been assumed to occur during the acidolytic cleavage of protecting groups based on a ter-butyl moiety, by synthesizing Nin-tert-butyltryptophan in different ways. It was found to be absolutely identical with a "modified tryptophan" which was isolated after the total synthesis of a gastrin analogue; Nin-tert-butyl-tryptophan peptides are formed as the main products of a tert-butylation reaction, the mechanism of which is not very clear yet. The proof for a Nin-tert-butylation of tryptophan was obtained by spectroscopic methods, in particular mass spectrometry and nuclear magnetic resonance spectroscopy.
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008722:Methods; D010455:Peptides / Q000138:chemical synthesis*; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D014364:Tryptophan / Q000031:analogs & derivatives*
chemical_list: D010455:Peptides; C018671:N-tert-butyl-tryptophan; D014364:Tryptophan
vernacular_title: Nebenreaktionen bei Peptidsynthesen, III. Synthese und Charakterisierung von Nin-tert-butylierten Tryptophan-derivaten.