1,3-disubstituted benzazepines as novel, potent, selective neuropeptide YY1 receptor antagonists

A novel series of potent and selective non-peptide neuropeptide Y (NPY) Y1 receptor antagonists, having benzazepine nuclei, have been designed, synthesized, and evaluated for activity. Chemical modification of the R-1 and R-3 substituents in structure 1 (Chart 1) yields several compounds that show high affinity for the Y1 receptor (K-i values of less than 10 nM). SAR studies revealed that introduction of an isopropylurea group at R-1 and a 3-(benzo-condensed-urea) group, 3-(fluorophenylurea) group, or a 3-(N-(4-hydroxyphenyl)guanidine) group at R-3 in structure 1 afforded potent and subtype-selective NPY Y1 receptor antagonists. 3-(3-(Benzothiazol-6-yl)ureido)-1-N-(3-(N'-(3-isopropylureido))benzyl)-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one (21), which was one of the most potent derivatives, competitively inhibited specific [I-125]peptide YY (PW) binding to Y1 receptors in human neuroblastoma SK-N-MC cells (K-i = 5.1 nM). 21 not only inhibited the Y1 receptor-mediated increase in cytosolic free Ca2+ concentration in SK-N-MC cells but also antagonized the Y1 receptor-mediated inhibitory effect of peptide YY on gastrin-induced histamine release in rat enterochromaffin-like cells. 21 showed no significant affinity in 17 receptor binding assays including Y2, Y4, and Y5 receptors.