AMINO-ACIDS AND PEPTIDES .233. SYNTHESIS OF PEPTIDES INFLUENCING GROWTH-HORMONE RELEASE

A solid phase peptide synthesis of 17 growth hormone (GH) releasing pe ptide analogues Ia - IIIc for their use in a pharmacological assay on GH release is described. While the linear peptide amides Ia - Ij were synthesized on p-methylbenzhydrylamine resin using Boc strategy, and c leaved by HF in the presence of scavengers the linear peptide amides I k and Il were prepared on Merrifield benzyl ester type resin using Fmo c strategy and cleaved by ammonolysis. The deleted peptide amides IIa and IIb were obtained as by-products during HPLC purification of analo gues Ic and Id. The linear precursors of cyclic peptides IIIa - IIIc w ere also prepared on Merrifield resin and cleaved under mild alkaline conditions. Their cyclization was performed in solution by diphenylpho sphoryl azide.