The synthesis of a new class of oxytocin antagonists, with significantly mo
dified C-terminal part, is described. The chemistry of the Mitsunobu reacti
on was applied to obtain the key derivatives. In spite of the extensive mod
ifications of previously described compound F792, the peptides retain biolo
gical activity as oxytocin antagonists. (C) 1999 Elsevier Science Ltd. All
rights reserved.