[Direct tert-butylation of tryptophan: preparation of 2,5,7-tri-tert-butyltryptophan (author's transl)]. / Direkte tert-Butylierung des Tryptophans. Herstellung von 2,5,7-Tri-tert-butyltryptophan.

The tert-butylation of free tryptophan under simulated conditions of acidolytic cleavage of protecting groups being based on a tert-butyl moiety does finally yield the tri-substituted amino acid as a main product, namely 2,5,7-tri-tert-butyltryptophan. The structural elucidation of this substance and other tert-butylated products, which were isolated mostly in a pure form, was achieved by means of spectroscopic methods, in particular mass spectrometry and nuclear magnetic resonance spectroscopy.