New delta-receptor antagonists.

: A new delta-selective opiate antagonist has been synthesised in which the two glycine residues of diallyl leucine enkephalin have been replaced by 4-aminobenzoic acid. The compound has a different conformation to that of ICI 174,864 (N,N-diallyl-Tyr-Aib-Aib-Phe-Leu).