New (R)-Cbenzamid~ 50xopentanoic acid derivatives were synthesized by a stereoconservative procedure and evaluated in vitro for their capacity to inhibit the binding of [1251](BH)-CCK-8 to either rat peripheral (CCK-A) or central (CCK-B) CCK receptors, or the binding of [3H] pentagastrin to rabbit gastric glands, as well as to inhibit, in vivo, the acid secretion induced by pentagastrin infusion in the perfused rat stomach. The parent ...