Pyrimidone-based series of glucokinase activators with alternative donor–acceptor motif

Transition-Metal-Catalyzed Silylation and Borylation of C-H Bonds for the Synthesis and Functionalization of Complex Molecules

The functionalization of C-H bonds in organic molecules containing functional groups has been one of the holy grails of catalysis. One synthetically important approach to the diverse functionalization of C-H bonds is the catalytic silylation or borylation of C-H bonds, which enables a broad array of downstream transformations to afford diverse structures. Advances in both undirected and directed methods for the transition-metal-catalyzed silylation and borylation of C-H bonds have led to their rapid adoption in early-, mid-, and late-stage of the synthesis of complex molecules. In this Review, we review the application of the transition-metal-catalyzed silylation and borylation of C-H bonds to the synthesis of bioactive molecules, organic materials, and ligands. Overall, we aim to provide a picture of the state of art of the silylation and borylation of C-H bonds as applied to the synthesis and modification of diverse architectures that will spur further application and development of these reactions.

A comprehensive review on glucokinase activators: Promising agents for the treatment of Type 2 diabetes

Glucokinase is a key enzyme which converts glucose into glucose-6-phosphate in the liver and pancreatic cells of the human. In the liver, glucokinase promotes the synthesis of glycogen, and in the pancreas, it helps in glucose-sensitive insulin release. It serves as a "glucose sensor" and thereby plays an important role in the regulation of glucose homeostasis. Due to this activity, glucokinase is considered as an attractive drug target for type 2 diabetes. It created a lot of interest among the researchers, and several small molecules were discovered. The research work was initiated in 1990. However, the hypoglycemic effect, increased liver burden, and loss of efficacy over time were faced during clinical development. Dorzagliatin, a novel glucokinase activator that acts on both the liver and pancreas, is in the late-stage clinical development. TTP399, a promising hepatoselective GK activator, showed a clinically significant and sustained reduction in glycated hemoglobin with a low risk of adverse effects. The successful findings generated immense interest to continue further research in finding small molecule GK activators for the treatment of type 2 diabetes. The article covers different series of GK activators reported over the past decade and the structural insights into the GK-GK activator binding which, we believe will stimulate the discovery of novel GK activators to treat type 2 diabetes.

2-Carbamimidoylbenzoic Acid as a New Effective and Available Precursor for the Synthesis of Substituted 2-(Pyrimidin-2-yl)benzoic Acids

A new approach to the synthesis of 2-(pyrimidin-2-yl)benzoic acids based on the ring contraction of the 2-carbamimidoylbenzoic acid [(2-amidinobenzoic) acid] with 1,3-dicarbonyl compounds and their synthetic equivalents has been developed. The intramolecular condensation of the obtained acids with 1,3-dielectrophiles proceeds with the formation of the 4,6-dihydropyrimido[2,1-a]isoindole-4,6-dione system, the pyrrolidone ring of which is easily opened under the action of weak nucleophiles. The reaction of 2-amidinobenzoic acid with chromones, which have an aryloxy group at 3-position does not stop at the step of pyrimidine ring formation and undergoes further spontaneous cyclization into 2-(benzo[4,5]furo[3,2-d]pyrimidin-2-yl)benzoic acids.

Recent Developments in Medicinal Chemistry of Allosteric Activators of Human Glucokinase for Type 2 Diabetes Mellitus Therapeutics

BACKGROUND

Glucokinase (GK), a cytoplasmic enzyme catalyzes the metabolism of glucose to glucose- 6-phosphate with the help of ATP and aids in the controlling of blood glucose levels within the normal range in humans. In pancreatic β-cells, it plays a chief role by controlling the glucose-stimulated secretion of insulin and in liver hepatocyte cells, it controls the metabolism of carbohydrates. GK acts as a promising drug target for the pharmacological treatment of patients with type 2 diabetes mellitus (T2DM) as it plays an important role in the control of carbohydrate metabolism.

METHODS

Data used for this review was based on the search from several science databases as well as various patent databases. The main data search terms used were allosteric GK activators, diabetes mellitus, type 2 diabetes, glucokinase, glucokinase activators and human glucokinase.

RESULTS

This article discusses an overview of T2DM, the biology of GK, the role of GK in T2DM, recent updates in the development of small molecule GK activators reported in recent literature, mechanism of action of GK activators and their clinical status.

CONCLUSION

GK activators are the novel class of pharmacological agents that enhance the catalytic activity of GK enzyme and display their antihyperglycemic effects. Broad diversity of chemical entities including benzamide analogues, carboxamides, acrylamides, benzimidazoles, quinazolines, thiazoles, pyrimidines, pyridines, orotic acid amides, amino acid derivatives, amino phosphates and urea derivatives have been synthesized in past two decades as potent allosteric activators of GK. Presently, the pharmaceutical companies and researchers are focusing on the design and development of liver-selective GK activators for preventing the possible adverse effects associated with GK activators for the long-term treatment of T2DM.

Design, synthesis and evaluation of novel 3,5-disubstituted benzamide derivatives as allosteric glucokinase activators

Glucokinase (GK) is the key enzyme expressed in β-cells of pancreas and liver hepatocytes and helps in the maintenance of blood glucose levels in normal range. Activators of GK are the novel category of drug candidates which activate GK enzyme allosterically and show their antidiabetic activity. A new series of 3,5-disubstituted benzamide analogues was designed, synthesized and evaluated as GK activators by in vitro assay as well as in silico docking studies followed by evaluation of antihyperglycemic activity in animal model. Amongst the synthesized derivatives, compounds 5c, 5f, 5i, 6c, 6e and 6h displayed excellent in vitro GK activation. Compounds 6c and 6e exhibited highest antihyperglycemic activity in oral glucose tolerance test in animal model. Compound 6e displayed most significant antihyperglycemic activity and comparable to that of standard drug in animal studies. In addition, antihyperglycemic activity of the synthesized molecules was further supported by the in silico docking studies of the synthesized derivatives in the allosteric site of GK protein.

Strain analysis of protein structures and low dimensionality of mechanical allosteric couplings

In many proteins, especially allosteric proteins that communicate regulatory states from allosteric to active sites, structural deformations are functionally important. To understand these deformations, dynamical experiments are ideal but challenging. Using static structural information, although more limited than dynamical analysis, is much more accessible. Underused for protein analysis, strain is the natural quantity for studying local deformations. We calculate strain tensor fields for proteins deformed by ligands or thermal fluctuations using crystal and NMR structure ensembles. Strains-primarily shears-show deformations around binding sites. These deformations can be induced solely by ligand binding at distant allosteric sites. Shears reveal quasi-2D paths of mechanical coupling between allosteric and active sites that may constitute a widespread mechanism of allostery. We argue that strain-particularly shear-is the most appropriate quantity for analysis of local protein deformations. This analysis can reveal mechanical and biological properties of many proteins.

Structural insight into the glucokinase-ligands interactions. Molecular docking study

Glucokinase (GK) plays a key role in the regulation of hepatic glucose metabolism. Inactivation of GK is associated with diabetes, and an increase of its activity is linked to hypoglycemia. Possibility to regulate the GK activity using small chemical compounds as allosteric activators induces the scientific interest to the study of the activation mechanism and to the development of new allosteric glucokinase activators. Interaction of glucokinase with ligands is the first step of the complicated mechanism of regulation of the GK functioning. In this paper, we study the interaction of GK with native (glucose) and synthetic (allosteric activators) ligands using molecular docking method. Calculations demonstrate the ability of molecular docking programs to accurately reproduce crystallized ligand poses and conformations and to calculate a free energy of binding with satisfactory accuracy. Correlation between the free energy of binding and the bioactivity of activators is discussed. These results provide a new insight into protein-ligand interactions and can be used for the engineering of new activators.

Simple Predictive Models of Passive Membrane Permeability Incorporating Size-Dependent Membrane-Water Partition

We investigate the relationship between passive permeability and molecular size, in the context of solubility-diffusion theory, using a diverse compound set with molecular weights ranging from 151 to 828, which have all been characterized in a consistent manner using the RRCK cell monolayer assay. Computationally, each compound was subjected to extensive conformational search and physics-based permeability prediction, and multiple linear regression analyses were subsequently performed to determine, empirically, the relative contributions of hydrophobicity and molecular size to passive permeation in the RRCK assay. Additional analyses of Log D and PAMPA data suggest that these measurements are not size selective, a possible reason for their sometimes weak correlation with cell-based permeability.

A patent review of glucokinase activators and disruptors of the glucokinase--glucokinase regulatory protein interaction: 2011-2014

INTRODUCTION

Glucokinase (GK) is a key regulator of glucose homeostasis, and development of small molecule activators of this enzyme represents a promising new approach for the treatment of type 2 diabetes mellitus.

AREAS COVERED

This manuscript reviews small molecule patent disclosures between late 2011 and February 2014 for both GK activators (GKAs) and GK-glucokinase regulatory protein (GK-GKRP) disruptors. The review is organized by company and structural class.

EXPERT OPINION

The field of GKA research continues to progress, driven by research across many organizations. To date, > 20 candidates have entered clinical development with the most advanced in Phase II trials. Despite promising efficacy, a significant number of early candidates have been discontinued for various reasons including increased risk of hypoglycemia and lack of durability. Recent work in the field has focused on liver-selective activators, which have shown lower hypoglycemia risk, including the development of novel GK-GKRP disruptors that act to indirectly increase hepatic GK activity.

NIS-mediated regioselective amidation of indole with quinazolinone and pyrimidone

A mild, metal-free condition was developed for the direct regioselective C2 amidation of indoles and pyrroles with quinazolinone and pyrimidone derivatives in intermolecular fashion, which led to novel indolyl/pyrrolyl quinazolinone and pyrimidone derivatives in moderate to good yields.