Synthesis and SAR studies of bicyclic amine series GPR119 agonists

Reductive Transamination of Pyridinium Salts to N-Aryl Piperidines

Saturated N-heterocycles are found in numerous bioactive natural products and are prevalent in pharmaceuticals and agrochemicals. While there are many methods for their synthesis, each has its limitations, such as scope and functional group tolerance. Herein, we describe a rhodium-catalyzed transfer hydrogenation of pyridinium salts to access N-(hetero)aryl piperidines. The reaction proceeds via a reductive transamination process, involving the initial formation of a dihydropyridine intermediate via reduction of the pyridinium ion with HCOOH, which is intercepted by water and then hydrolyzed. Subsequent reductive amination with an exogenous (hetero)aryl amine affords an N-(hetero)aryl piperidine. This reductive transamination method thus allows for access of N-(hetero)aryl piperidines from readily available pyridine derivatives, expanding the toolbox of dearomatization and skeletal editing.

Anti-diabetic drugs recent approaches and advancements

Diabetes is one of the major diseases worldwide and is the third leading cause of death in the United States. Anti-diabetic drugs are used in the treatment of diabetes mellitus to control glucose levels in the blood. Most of the drugs are administered orally, except for a few of them, such as insulin, exenatide, and pramlintide. In this review, we are going to discuss seven major types of anti-diabetic drugs: Peroxisome proliferator-activated receptor (PPAR) agonist, protein tyrosine phosphatase 1B (PTP1B) inhibitors, aldose reductase inhibitors, α-glucosidase inhibitors, dipeptidyl peptidase IV (DPP-4) inhibitors, G protein-coupled receptor (GPCR) agonists and sodium-glucose co-transporter (SGLT) inhibitors. Here, we are also discussing some of the recently reported anti-diabetic agents with its multi-target pharmacological actions. This review summarises recent approaches and advancement in anti-diabetes treatment concerning characteristics, structure-activity relationships, functional mechanisms, expression regulation, and applications in medicine.

G Protein-Coupled Receptor 119 (GPR119) Agonists for the Treatment of Diabetes: Recent Progress and Prevailing Challenges

In this Perspective, recent advances and challenges in the development of GPR119 agonists as new oral antidiabetic drugs will be discussed. Such agonists are expected to exhibit a low risk to induce hypoglycemia as well as to have a beneficial impact on body weight. Many pharmaceutical companies have been active in the search for GPR119 agonists, making it a highly competitive area in the industrial environment. Several GPR119 agonists have been entered into clinical studies, but many have failed either in phase I or II and none has progressed beyond phase II. Herein we describe the strategies chosen by the different medicinal chemistry teams in academia and the pharmaceutical industry to improve potency, physicochemical properties, pharmacokinetics, and the safety profile of GPR119 agonists in the discovery phase in order to improve the odds for successful development.

Indanes--Properties, Preparation, and Presence in Ligands for G Protein Coupled Receptors

The indane (2,3-dihydro-1H-indene) ring system is an attractive scaffold for biologically active compounds due to the combination of aromatic and aliphatic properties fused together in one rigid system. This bicyclic structure provides a wide range of possibilities to incorporate specific substituents in different directionalities, thus being an attractive scaffold for medicinal chemists. Notably, many indane-based compounds are being used in the clinic to treat various diseases, such as indinavir, an HIV-1 protease inhibitor; indantadol, a potent Monoamine Oxidase (MAO)-inhibitor; the amine uptake inhibitor indatraline; and the ultra-long-acting β-adrenoceptor agonist indacaterol. Given the diversity of targets these drugs act on, one could argue that the indane ring system is a privileged substructure. In the present review, the synthetic and medicinal chemistry of the indane ring system is described. In more detail, it contains a comprehensive overview of compounds bearing the indane substructure with G protein coupled receptor (GPCR) activity, with particular emphasis on their structure-activity relationships (SAR).

Palladium-catalyzed hydroxylation of aryl and heteroaryl halides enabled by the use of a palladacycle precatalyst

A method for the hydroxylation of aryl and heteroaryl halides, promoted by a catalyst based on a biarylphosphine ligand tBuBrettPhos (L5) and its corresponding palladium precatalyst (1), is described. The reactions allow the cross-coupling of both potassium and cesium hydroxides with (hetero)aryl halides to afford a variety of phenols and hydroxylated heteroarenes in high to excellent yield.

meta-Chloroperbenzoic acid (mCPBA): a versatile reagent in organic synthesis

This review aims to collect and discuss the synthetic applications of meta-chloroperbenzoic acid (mCPBA) over the past few decades.

A categorical structure-activity relationship analysis of GPR119 ligands

The categorical structure-activity relationship (cat-SAR) expert system has been successfully used in the analysis of chemical compounds that cause toxicity. Herein we describe the use of this fragment-based approach to model ligands for the G protein-coupled receptor 119 (GPR119). Using compounds that are known GPR119 agonists and compounds that we have confirmed experimentally that are not GPR119 agonists, four distinct cat-SAR models were developed. Using a leave-one-out validation routine, the best GPR119 model had an overall concordance of 99%, a sensitivity of 99%, and a specificity of 100%. Our findings from the in-depth fragment analysis of several known GPR119 agonists were consistent with previously reported GPR119 structure-activity relationship (SAR) analyses. Overall, while our results indicate that we have developed a highly predictive cat-SAR model that can be potentially used to rapidly screen for prospective GPR119 ligands, the applicability domain must be taken into consideration. Moreover, our study demonstrates for the first time that the cat-SAR expert system can be used to model G protein-coupled receptor ligands, many of which are important therapeutic agents.

Conformational restriction in a series of GPR119 agonists: differences in pharmacology between mouse and human

A series of conformationally restricted GPR119 agonists were prepared based around a 3,8-diazabicyclo[3.2.1]octane scaffold. Examples were found to have markedly different pharmacology in mouse and human despite similar levels of binding to the receptor. This highlights the large effects on GPCR phamacology that can result from small structural changes in the ligand, together with inter-species differences between receptors.