Studies on Polypeptides. XXX. Synthetic Peptides Related to the N-Terminus of Bovine Pancreatic Ribonuclease (Positions 8—13)^1-4

Syntheses are described of a series of peptides and peptide derivatives related to positions 8-13 in the amino acid sequence of bovine pancreatic ribonuclease A. In particular, the preparation is given of phenylalanylgluta-mylarginylglutamine, phenylalanylglutamylarginylgluta-minylhistidine amide, phenylalanylglutamylarginylgluta-minylhistidylmethionine, phenylalanylglutamylarginyl-glutamylhistidylmethionine, and phenylalanylglutamylar-ginylglutaminylhistidyl-α-amino-n-butyric acid. The hy-drazide of t-butyloxycarbonylphenylalanyl-γ-t-butylglu-tamylarginylglutamine served as the key intermediate in the preparation of some of the above mentioned compounds. “Carbobenzoxyhydrazides” played an important role as intermediates.