Synthèse de l'Asp(NH 2 ) 4 ‐oxytocine, de la Glu(NH 2 ) 5 ‐oxytocine et de l'Asp(NH 2 ) 4 ‐Glu(NH 2 ) 5 ‐oxytocine

Three analogues of oxytocin in which the side chains of the amino acids in position 4 and 5 have been shortened or lengthened, i.e. Asp(NH 2 ) 4 ‐Oxytocin, Glu(NH 2 ) 5 ‐Oxytocin and Asp(NH 2 ) 4 ‐Glu(NH 2 ) 8 ‐Oxytocin, have been synthesized according to the scheme (3 + 6). Only the first of these analogues, which contains one CH 2 ‐group less than oxytocin, still exhibits important oxytocic activities.