Preparation and receptor binding affinities of cyclic C-terminal neurotensin (8–13) and (9–13) analogues

Cyclic analogues of neurotensin (NT) C-terminal fragments NT(8–13) and NT(9–13) were produced via intramolecular nucleophilic substitution of the Tyr(11) phenoxide anion on a 6-bromohexanoyl side chain substituted at position 8 or 9 and tested for NT receptor binding affinity.