Duncan Charles Miller

Investigation of the effect of molecular properties on the binding kinetics of a ligand to its biological target

A database of binding kinetic data across multiple targets has been created. Analysis of this database provides insights into trends for the effects of physicochemical properties (molecular weight, clogP, rotatable bond count) on the dissociation kinetics of ligands from their biological targets.

SAR mining and its application to the design of TRPA1 antagonists

Given the large amounts of screening data now available, empirical methods derived from matched-molecular pairs are being used as a means for suggesting bioisosteric replacements to the medicinal chemist. The pairwise analysis of compounds has been extended to the pairwise analysis of series to bring further context to these suggestions. A validation dataset derived from recent literature has been used to demonstrate that, given a series of active compounds, this approach would be expected to predict a more potent compound, if it exists, in around 46% of cases. The approach has been successfully applied to a series of TRPA1 antagonists.

Optimising metabolic stability in lipophilic chemical space: the identification of a metabolically stable pyrazolopyrimidine CRF-1 receptor antagonist.

Balancing potency and metabolic stability in a target which favours lipophilic ligands is a considerable challenge. Here we describe two strategies employed to achieve this balance in a series of pyrazolopyrimidine CRF antagonists: moderation of lipophilicity, and incorporation of a metabolically stable lipophilic group.

Discovery of potent, metabolically stable purine CRF-1 antagonists with differentiated binding kinetic profiles

Optimisation of the potency of a bicyclic CRF antagonist whilst retaining metabolic stability is described. A core change and incorporation of metabolically stable lipophilic groups resulted in a further potency gain without increasing metabolic liability. Pharmacological investigation of binding kinetics led to the identification of compound 25, a sub-nanomolar CRF-1 antagonist with slow dissociation kinetics and an encouraging pharmacokinetic profile.

Highly potent and selective chiral inhibitors of PDE5: an illustration of Pfeiffer's rule.

A series of potent chiral PDE5 inhibitors are described that are based on the sildenafil architecture but exhibit much greater selectivity over PDE6. Eudismic analysis of the SAR in this series provided a clear illustration of Pfeiffers rule and indicated that the chiral motif was involved in a highly-stereoselective interaction with PDE5. This PDE5 specificity translated to levels of selectivity over PDE6 that were hitherto unprecedented in the sildenafil scaffold. UK-371,800 (compound 8) was identified as a development candidate from this series that married sildenafil-like molecular properties with high selectivity over PDE6. Clinical data confirm that UK-371,800 has markedly superior human pharmacokinetics to a previously-described higher molecular weight achiral analogue in this template (compound 1).

Synthesis and Activity of Putative Small-Molecule Inhibitors of the F-Box Protein SKP2*

The tetrahydropyran 4-(((3-(2,2-dimethyltetrahydro-2H-pyran-4-yl)-4-phenylbutyl)amino)methyl)-N,N-dimethylaniline was reported to disrupt the SCFSKP2 E3 ligase complex. Efficient syntheses of this tetrahydropyran derivative and analogues, including the des-dimethyl derivative 4-(((3-(tetrahydro-2H-pyran-4-yl)-4-phenylbutyl)amino)methyl)-N,N-dimethylaniline, are described. The enantiomers of the des-dimethyl compound were obtained using Evans’ chiral auxiliaries. Structure–activity relationships for these tetrahydropyrans and analogues have been determined by measurement of growth-inhibitory activities in HeLa cells, which indicated a non-specific mechanism of action that correlates with inhibitor lipophilicity. However, preliminary data with (R)- and (S)-4-(((3-(tetrahydro-2H-pyran-4-yl)-4-phenylbutyl)amino)methyl)-N,N-dimethylaniline showed enantioselective inhibition of the degradation of p27 in a cell-based assay that acts as a reporter of SKP2 activity.

Discovery and optimisation of potent and highly subtype selective Nav1.8 inhibitors with reduced cardiovascular liabilities

Voltage-gated sodium channels, in particular Nav1.8, can be targeted for the treatment of neuropathic and inflammatory pain. Herein, we describe the discovery and optimisation of a Nav1.8 inhibiting phenyl imidazole series that delivers chemical equity that possesses high potency and selectivity and is capable of demonstrating good oral pharmacokinetics.