Christina L. Newton

Unexpected enhancement of thrombin inhibitor potency with o-aminoalkylbenzylamides in the P1 position.

Thrombin inhibitors incorporating o-aminoalkylbenzylamides in the P1 position were designed, synthesized and found to have enhanced potency and selectivity in several different structural classes. X-ray crystallographic analysis of compound 24 bound in the alpha-thrombin-hirugen complex provides an explanation for these unanticipated results.

Design and synthesis of potent and selective macrocyclic thrombin inhibitors

A series of potent and selective proline- and pyrazinone-based macrocyclic thrombin inhibitors is described. Detailed SAR studies led to the incorporation of specific functional groups in the tether that enhanced functional activity against thrombin and provided exquisite selectivity against trypsin and tPA. X-ray crystallography and molecular modeling studies revealed the inhibitor-enzyme interactions responsible for this selectivity.

C6 modification of the pyridinone core of thrombin inhibitor L-374,087 as a means of enhancing its oral absorption.

1 (L-374,087) is a potent, selective, efficacious, and orally bioavailable thrombin inhibitor that contains a core 3-amino-2-pyridinone moiety. Replacement of the C6 pyridinone methyl group of 1 by a propyl group gave 5 (L-375,052), which retained all the excellent properties of 1, and also yielded higher plasma levels after oral dosing in dogs and rats.

Structure-based design of novel groups for use in the P1 position of thrombin inhibitor scaffolds. Part 2: N-acetamidoimidazoles.

Guided by X-ray crystallography of thrombin-inhibitor complexes and molecular modeling, alkylation of the N1 nitrogen of the imidazole P1 ligand of the pyridinoneacetamide thrombin inhibitor 1 with various acetamide moieties furnished inhibitors with significantly improved thrombin potency, trypsin selectivity, functional in vitro anticoagulant potency and in vivo antithrombotic efficacy. In the pyrazinoneacetamide series, oral bioavailability was also improved.

Design, synthesis and SAR of a series of 1,3,5-trisubstituted benzenes as thrombin inhibitors.

A novel 1,3,5-trisubstituted benzamide thrombin inhibitor template was designed via hybridization of a known aminopyridinoneacetamide and a known 1,3,5-trisubstituted phenyl ether. Optimization of this lead afforded a novel potent series of biaryl 1,3,5-trisubstituted benzenes with excellent functional anticoagulant potency.

P3 optimization of functional potency, in vivo efficacy and oral bioavailability in 3-aminopyrazinone thrombin inhibitors bearing non-charged groups at the P1 position

Although the S3 pocket of the thrombin active site is lined with lipophilic amino acid residues, the accommodation of polarity within the lipophilic P3 moiety of small molecule inhibitors is possible provided that the polar functionality is capable of pointing away from the binding pocket outwards toward solvent while simultaneously allowing the lipophilic portion of the P3 ligand to interact with the S3 amino acid residues. Manipulation of this motif provided the means to effect optimization of functional potency, in vivo antithrombotic efficacy and oral bioavailability in a series of 3-aminopyrazinone thrombin inhibitors which contained non-charged groups at the P1 position.