PREPARATION OF Nα‐BOC‐Nε‐P‐BRZ‐LYSINE AND Nα‐BOC‐0‐M‐BRBZL‐TYROSINE AND THEIR USE FOR THE SOLID PHASE SYNTHESIS OF AN OCTAPEPTIDE OCCURRING IN THE HGH MOLECULE

Crystalline Nα‐t‐butyloxycarbonyl‐Nε‐(p‐bromobenzyloxycarbonyl)lysine has been synthesized and employed in the solid phase synthesis of the octapeptide H‐Phe‐Lys‐Gln‐Thr‐Tyr‐Ser‐Lys‐Phe‐OH(I) which corresponds to positions 138–145 in human growth hormone. Crystalline Nα‐t‐butyloxycarbonyl‐O‐(m‐bromobenzyl)tyrosine has also been synthesized; a second synthesis of I was accomplished by use of both of these new amino acid derivatives. All amino acids employed in this work are of the l configuration. The abbreviations used are: tlc, thin layer chromatography; TFA, trifluoroacetic acid; EtOH, absolute ethanol; DMF, dimethylformamide; Boc, Nα‐t‐butyloxycarbonyl; Z, benzyloxycarbonyl; Bzl, benzyl; HGH, human pituitary growth hormone.