The discovery of 6-[2-(5-chloro-2-{[(2,4-difluorophenyl)methyl]oxy}phenyl)-1-cyclopenten-1-yl]-2-pyridinecarboxylic acid, GW848687X, a potent and selective prostaglandin EP1 receptor antagonist for the treatment of inflammatory pain.

The discovery of a series of selective EP1 receptor antagonists based on a 1,2-diarylcyclopentene template is described. After defining the structural requirements for EP1 potency and selectivity, heterocyclic rings were incorporated to reduce logD and improve in vitro pharmacokinetic properties. The 2,6-substituted pyridines and pyridazines gave an appropriate balance of potency, in vivo pharmacokinetic properties and a low potential for inhibiting a range of CYP450 enzymes.

Discovery of novel biaryl heterocyclic EP1 receptor antagonists.

We describe the generation of novel EP(1) receptor antagonists by investigation of thiophene isosteres. In addition, we disclose preliminary in vitro and in vivo DMPK for selected compounds.

The design of potent, non-peptidic inhibitors of hepatitis C protease.

The pyrrolidine-5,5-trans-lactam template was used to design small, neutral, mechanism-based inhibitors of hepatitis C NS3/4A protease displaying potent activity in the replicon cell-based assay. The activity of this series is not dependent upon its chemical reactivity and molecules have been synthesised which combine enhanced biochemical potency with improved plasma stability. Promising initial pharmacokinetic data indicating the potential for further optimisation of this series into low molecular weight, drug-like inhibitors is presented.

Pyrrolidine-5,5-trans-lactams. 2. The use of X-ray crystal structure data in the optimization of P3 and P4 substituents.

[reaction: see text] In this, the second of two letters, we describe the elaboration of the pyrrolidine-5,5-trans-lactam template to delineate the requirements for optimal substitution of the pyrrolidine and lactam nitrogen atoms. Central to the strategy is the use of rapid iterative synthesis in conjunction with X-ray crystal structure determination of ligand-protein complexes.

Pyrrolidine-5,5-trans-lactams. 1. Synthesis and incorporation into inhibitors of hepatitis C virus NS3/4A protease.

[reaction: see text] In this, the first of two letters, we outline the use of the pyrrolidine-5,5-trans-lactam template to design small, neutral, mechanism-based inhibitors of hepatitis C NS3/4A protease. The hitherto unreported reaction of the acyl iminium ion precursor 4 with dialkyl-substituted silyl ketene acetals (e.g.

Design and synthesis of ethyl pyrrolidine-5,5-trans-lactams as inhibitors of hepatitis C virus NS3/4A protease.

Using a pyrrolidine-5,5-trans-lactam template, we have designed small, neutral, mechanism-based inhibitors of hepatitis C NS3/4A protease. Compound 11a, with an alpha-ethyl P1 substituent and a Boc-valine substituent at the pyrrolidine nitrogen, has an IC(50)=30 microM.