Menschliches Calcitonin. V ). Aufbau und Charakterisierung des geschützten Synthese‐Zwischenprodukts Calcitonin M‐(1‐10)‐decapeptid

The present report describes in detail the synthesis and characterisation of the protected Calcitonin M decapeptide 1–10, , a key intermediate in the synthesis of Calcitonin M. I. was obtained from the openchain precursor Boc‐Cys (Trt)‐Gly‐Asn‐Leu‐Ser (But)‐Thr (But)‐Cys (Trt)‐Met‐Leu‐Gly‐OH (II) by oxidation with iodine in a yield of 70%, after purification by counter‐current distribution. II was prepared by fragment coupling of the sequences 1–4 and 5–10. The free calcitonin M (1–10)‐decapeptide, obtained from I by removal of the protecting groups by acidolysis, has no hypocalcaemic activity and does not inhibit specific binding of calcitonin M to its antibodies in rabbit serum.