Design, synthesis and SAR of novel ethylenediamine and phenylenediamine derivatives as factor Xa inhibitors.

We previously reported on a series of cyclohexanediamine derivatives as highly potent factor Xa inhibitors. Herein, we describe the modification of the spacer moiety to discover an alternative scaffold. Ethylenediamine derivatives possessing a substituent at the C1 position in S configuration and phenylenediamine derivatives possessing a substituent at the C5 position demonstrated moderate to strong anti-fXa activity. Further SAR studies led to the identification of compound 30 h which showed both good in vitro activity (fXa IC(50) = 2.2 nM, PTCT2 = 3.9 μM) and in vivo antithrombotic efficacy.