PROTECTION OF THE TRYPTOPHAN INDOLE RING IN PEPTIDE SYNTHESIS. USE OF A NEW DERIVATIVE, Nin-2,2,2-TRICHLOROETHOXYCARBONYLTRYPTOPHAN

Abstract
The 2,2,2-trichloroethoxycarbonyl (Troc) group attached at the Nin function of tryptophan by acylation with Troc-Cl in the presence of a catalytic amount of tetra-n-butylammonium hydrogensulfate can be quantitatively removed either by cadmium dust in acetic acid or under basic conditions, e.g., hydrazine hydrate and NaOH, but is resistant to strong acidic conditions.