Pyrazole-based factor Xa inhibitors containing N-arylpiperidinyl P4 residues.

The synthesis, SAR, pharmacokinetic profile, and modeling studies of both monocyclic and fused pyrazoles containing substituted N-arylpiperidinyl P4 moieties that are potent and selective factor Xa inhibitors will be discussed. Fused pyrazole analog 16a, with a 2'-methylsulfonylphenyl piperidine P4 group, was shown to be the best compound in this series (FXa Ki = 0.35 nM) based on potency, selectivity, and pharmacokinetic profile.

Discovery of 1-(2-aminomethylphenyl)-3-trifluoromethyl-N- [3-fluoro-2'-(aminosulfonyl)[1,1'-biphenyl)]-4-yl]-1H-pyrazole-5-carboxyamide (DPC602), a potent, selective, and orally bioavailable factor Xa inhibitor(1).

Factor Xa, a serine protease, is at the critical juncture between the intrinsic and extrinsic pathways of the coagulation cascade. Inhibition of factor Xa has the potential to provide effective treatment for both venous and arterial thrombosis. We recently described a series of meta-substituted phenylpyrazoles that are highly potent, selective, and orally bioavailable factor Xa inhibitors. In this paper we report our efforts to further optimize the selectivity profile of our factor Xa inhibitors with a series of ortho- and/or para-substituted phenylpyrazole derivatives. The most potent compounds display sub-nanomolar inhibition constants for factor Xa and show greater than 1000-fold selectivity against other serine proteases. These compounds are also effective in a rabbit model of arteriovenous shunt thrombosis. Optimization of this series led to the preclinical development of DPC602, a 2-(aminomethyl)phenylpyrazole analogue, as a highly potent, selective, and orally bioavailable factor Xa inhibitor.

An Unusual Trifluoromethyl Elimination Reaction from the 4,4-Bis(trifluoromethyl)-5-hydroxyimidazoline Ring System.

A facile detrifluoromethylation was observed when 4,4-bis(trifluoromethyl)-5-hydroxyimidazoline 5 was treated with a variety of bases to afford the biologically interesting 4-(trifluoromethyl)imidazole analogs (9 and 10). A unique mechanism was proposed for this transformation, supported by isolating and trapping the hypothesized intermediates. Heating of 5 with Et(4)NCN in DMSO provided 19, which was clearly derived from the proposed intermediate 17. Finally, imidazole 9 was converted into the N-[2-phenyl-4-(trifluoromethyl)-1H-imidazol-5-yl]-N-methylbenzamide analogs, which were potential acyl CoA:cholesterol acyltransferase (ACAT) inhibitors.