5-(PIPERIDIN-2-YL)-1,4-BENZODIAZEPINES AND 5-(HOMOPIPERIDIN-2-YL)-1,4-BENZODIAZEPINES - HIGH-AFFINITY, BASIC LIGANDS FOR THE CHOLECYSTOKININ-B RECEPTOR
Jl. Castro et al., 5-(PIPERIDIN-2-YL)-1,4-BENZODIAZEPINES AND 5-(HOMOPIPERIDIN-2-YL)-1,4-BENZODIAZEPINES - HIGH-AFFINITY, BASIC LIGANDS FOR THE CHOLECYSTOKININ-B RECEPTOR, Journal of medicinal chemistry, 40(16), 1997, pp. 2491-2501
The design, synthesis, and biological activity of a series of high-aff
inity, basic ligands for the cholecystokinin-B receptor are described.
The compounds, which incorporate a piperidin-2-yl or a homopiperidin-
2-yl group attached to C-5 of a benzodiazepine core structure, are sub
stantially more basic (e.g., 9d, pK(a)=9.48) than previously reported
antagonists based on 5-amino-1,4-benzodiazepines (e.g., 5, pK(a)=7.1)
and have improved aqueous solubility. In view of their basicity, it wo
uld be tempting to speculate that the present series of compounds migh
t be binding to the CCK-B receptor in their protonated form. Compounds
such as 9d,e and 10d showed high affinity for this receptor (IC50 < 2
.5 nM) and very good selectivity over CCK-A (CCK-A/CCK-B > 2000), even
as the racemates. Additionally, a significantly improved in vivo half
-life was observed for a selection of compounds compared to the clinic
al candidate L-365,-260 (1).