Anthranilic acid based CCK1 antagonists: the 2-indole moiety may represent a "needle" according to the recent homonymous concept.

Recently we described an innovative class of non-peptide CCK(1) antagonists keeping appropriate pharmacophoric groups on the anthranilic acid employed as a molecular scaffold. The lead compound obtained, VL-0395, characterized by the presence of Phe and the 2-indole moiety at the C- and N-termini of anthranilic acid, respectively, is endowed with submicromolar affinity towards CCK(1) receptors. Thus, we have prepared and tested on CCK receptors a library of VL-0395 analogues in order to investigate the precise topological and essential key interactions of the 2-indole group of the lead with the CCK(1) receptor. The obtained results confirm that this group establishes very specific interactions with this receptor sub-site and may be viewed as a "needle" group.