The peptides of alpha-aminosuberic acid II. Synthesis of deamino-dicarba-eel-calcitonin sequence 1-9

The paper describes the synthesis of Asu6-octapeptide derivatives by condensing two alternative pentapeptide fragments with Asu-containing tripeptides. After partial deprotection these linear peptides compounds are subject to cyclization experiments aimed to give the N-terminal [1-9] sequence of deamino-dicarba-eel calcitonin. This is a key substance for the semi-synthesis of the respective analogues of eel calcitonin.