Darren Mckerrecher

An improved synthesis of bis(1,3-di-N-tert-butylimidazol-2-ylidene)palladium(0) and its use in C–C and C–N coupling reactions

A new, improved synthesis of [Pd{CN(tBu)(CH)2N(tBu)}2] (1) and its use as a catalyst in coupling reactions, including aminations, is presented. An interesting side product formed in the synthesis of 1, [Pd(?3-C4H7){(CN(tBu)(CH) 2N(tBu)}Cl] (2), is also discussed.

Use of small-molecule crystal structures to address solubility in a novel series of G protein coupled receptor 119 agonists: optimization of a lead and in vivo evaluation.

G protein coupled receptor 119 (GPR119) is viewed as an attractive target for the treatment of type 2 diabetes and other elements of the metabolic syndrome. During a program toward discovering agonists of GPR119, we herein describe optimization of an initial lead compound, 2, into a development candidate, 42. A key challenge in this program of work was the insolubility of the lead compound. Small-molecule crystallography was utilized to understand the intermolecular interactions in the solid state and resulted in a switch from an aryl sulphone to a 3-cyanopyridyl motif. The compound was shown to be effective in wild-type but not knockout animals, confirming that the biological effects were due to GPR119 agonism.

Dissociated non-steroidal glucocorticoid receptor modulators: an update on new compounds

Background: Glucocorticoids are the most potent anti-inflammatory drugs available and allow successful treatment of several chronic inflammatory and autoimmune diseases. The discovery of the molecular mechanisms of the glucocorticoid receptor (GR), and the recognition that activation and repression of gene expression could be addressed separately, opened the possibility of improving safety profiles by identifying ligands that predominantly induce repression over activation. Recent progress in the development of dissociated and other non-steroidal GR modulators is discussed here. Objective: To summarize the data and progress of current compounds reported in GR programs carried out by pharmaceutical companies. Methods: The review is primarily of patents and publications disclosed over the last two years. Results/conclusion: Although the mechanistic drivers for development of safer GR ligands have expanded from the basic transrepression/transactivation hypothesis, the concept appears to have led to the identification of some drug candidates that show dissociated in vitro profiles and improved in vivo therapeutic indices.

Matrix-based multiparameter optimisation of glucokinase activators: the discovery of AZD1092

Small molecule activators of the glucokinase enzyme have the potential to deliver a level of glycaemic control that is superior to current oral agents and hence have great promise as new therapies for Type 2 Diabetes. As such, attempts to discover glucokinase activators suitable for clinical development have been the focus of many major pharmaceutical research programmes. Here we show how property-based matrix optimisation has been used to improve the multi-parameter technical profile of the AstraZeneca series of glucokinase activators culminating in the discovery of the development candidate AZD1092.

Design of a potent, soluble glucokinase activator with increased pharmacokinetic half-life.

The continued optimization of a series of glucokinase activators is described, including attempts to understand the interplay between molecular structure and the composite parameter of unbound clearance. These studies resulted in the discovery of a new scaffold for glucokinase activators and further exploration of this scaffold led to the identification of GKA60. GKA60 maintains an excellent balance of potency and physical properties whilst possessing a significantly different, but complimentary, pre-clinical pharmacokinetic profile compared with the previously disclosed compound GKA50.

Property based optimisation of glucokinase activators – discovery of the phase IIb clinical candidate AZD1656

Glucokinase plays a central role in glucose homeostasis and small molecule activators of the glucokinase enzyme have been the subject of significant pharmaceutical research in the quest for agents capable of delivering improved glycaemic control. Here we describe our medicinal chemistry campaign to improve on our previously described development candidate in this area, AZD1092, focussed on removal of Ames liability and improved permeability characteristics. This work culminated in the superior compound AZD1656 which has progressed to phase 2 clinical trials.

Discovery, optimisation and in vivo evaluation of novel GPR119 agonists.

GPR119 is increasingly seen as an attractive target for the treatment of type II diabetes and other elements of the metabolic syndrome. During a programme aimed at developing agonists of the GPR119 receptor, we identified compounds that were potent with reduced hERG liabilities, that had good pharmacokinetic properties and that displayed excellent glucose-lowering effects in vivo. However, further profiling in a GPR119 knock-out (KO) mouse model revealed that the biological effects were not exclusively due to GPR119 agonism, highlighting the value of transgenic animals in drug discovery programs.

Overcoming retinoic acid receptor-α based testicular toxicity in the optimisation of glucokinase activators

Small molecule activators of the glucokinase enzyme have the potential to deliver a level of glycaemic control that is superior to current oral agents and hence have great promise as new therapies for Type 2 Diabetes. As such, attempts to discover glucokinase activators suitable for clinical development have been the focus of many major pharmaceutical research programmes. Here we describe how we have overcome a testicular toxicological liability in our pyridine acid lead series, which we show can be ascribed to antagonism of the retinoic acid receptor-α.

Circumventing Seizure Activity in a Series of G Protein Coupled Receptor 119 (GPR119) Agonists

Agonism of GPR119 is viewed as a potential therapeutic approach for the treatment of type II diabetes and other elements of metabolic syndrome. During progression of a previously disclosed candidate 1 through mice toxicity studies, we observed tonic-clonic convulsions in several mice at high doses. An in vitro hippocampal brain slice assay was used to assess the seizure liability of subsequent compounds, leading to the identification of an aryl sulfone as a replacement for the 3-cyano pyridyl group. Subsequent optimization to improve the overall profile, specifically with regard to hERG activity, led to alkyl sulfone 16. This compound did not cause tonic-clonic convulsions in mice, had a good pharmacokinetic profile, and displayed in vivo efficacy in murine models. Importantly, it was shown to be effective in wild-type (WT) but not GPR119 knockout (KO) animals, consistent with the pharmacology observed being due to agonism of GPR119.

Optimisation of aqueous solubility in a series of G protein coupled receptor 119 (GPR119) agonists

Improving aqueous solubility is a challenge frequently faced within drug discovery programs. Herein we describe increases in solubility in two sub-series of GPR119 agonists through reduction of lipophilicity together with hydrogen bond acceptor modulation. Small molecule X-ray crystallography was utilised to investigate effects on solid state interactions.