Compound 2 containing an aminomethylbenzoyl moiety as the S4 binding motif was synthesized in order to modulate hydrophlicity of anthranilamide-based factor Xa inhibitors with substituted biphenyl P4 groups. Structure-activity relationship studies around 2 have led to a series of potent factor Xa inhibitors which are highly active in the human plasma-based thrombin generation assay with 2XTG values less than 1 microM. Compound 55 shows strong antithrombotic activity in our rabbit deep vein thrombosis model, and also exhibits good oral bioavailability and a long half life in rats.