N-Aryl Isoleucine Derivatives as Angiotensin II AT(2) Receptor Ligands

A novel series of ligands for the recombinant human AT(2) receptor has been synthesized utilizing a fast and efficient palladium-catalyzed procedure for aminocarbonylation as the key reaction. Molybdenum hexacarbonyl [Mo(CO)(6)] was employed as the carbon monoxide source, and controlled microwave heating was applied. The prepared N-aryl isoleucine derivatives, encompassing a variety of amide groups attached to the aromatic system, exhibit binding affinities at best with K(i) values in the low micromolar range versus the recombinant human AT(2) receptor. Some of the new nonpeptidic isoleucine derivatives may serve as starting points for further structural optimization. The presented data emphasize the importance of using human receptors in drug discovery programs.