Antagonists. -Biphenyl analogues of selective non-peptidic hNK-3 receptor antagonists are synthesized maintaining the phenyl-quinoline-carboxy framework and incorporating a variety of substituents at C-4 to examine their effect on the anticipated biological activity. Two series of carboxylates and carboxamides are prepared and fifteen compounds are screened for their effect on the anticipated hNK-3 receptor antagonistic activity. Compounds (IIIb),, and (VIIa) show promising antagonistic activity with bromo derivative (IIIb) being the most active antagonist. Compounds (IIIa), (Va), and (IX) display moderate antagonistic effects while (Vb), (VIII), and (XIIa) exhibit weak antagonistic activity. Unexpectedly, some compounds reveal agonistic activity, cf. (X). -(SAUDI*, M. N. S.; ROSTOM, S. A. F.; FAHMY, H. T. Y.; EL ASHMAWY, I. M.; Arch. Pharm.