A comprehensive structure–activity analysis 2,3,5-trisubstituted 4,5-dihydro-4-oxo-3H-imidazo [4,5-c] pyridine derivatives as angiotensin II receptor antagonists: using 2D- and 3D-QSAR approach

Imidazopyridine, a promising scaffold with potential medicinal applications and structural activity relationship (SAR): recent advances

Imidazopyridine scaffold has gained tremendous importance over the past few decades. Imidazopyridines have been expeditiously used for the rationale design and development of novel synthetic analogs for various therapeutic disorders. A wide variety of imidazopyridine derivatives have been developed as potential anti-cancer, anti-diabetic, anti-tubercular, anti-microbial, anti-viral, anti-inflammatory, central nervous system (CNS) agents besides other chemotherapeutic agents. Imidazopyridine heterocyclic system acts as a key pharmacophore motif for the identification and optimization of lead structures to increase medicinal chemistry toolbox. The present review highlights the medicinal significances of imidazopyridines for their rationale development as lead molecules with improved therapeutic efficacies. This review further emphasis on the structure-activity relationships (SARs) of the various designed imidazopyridines to establish a relationship between the key structural features versus the biological activities.Communicated by Ramaswamy H. Sarma.

Pharmacological Potential and Synthetic Approaches of Imidazo[4,5-b]pyridine and Imidazo[4,5-c]pyridine Derivatives

The structural resemblance between the fused imidazopyridine heterocyclic ring system and purines has prompted biological investigations to assess their potential therapeutic significance. They are known to play a crucial role in numerous disease conditions. The discovery of their first bioactivity as GABA_A receptor positive allosteric modulators divulged their medicinal potential. Proton pump inhibitors, aromatase inhibitors, and NSAIDs were also found in this chemical group. Imidazopyridines have the ability to influence many cellular pathways necessary for the proper functioning of cancerous cells, pathogens, components of the immune system, enzymes involved in carbohydrate metabolism, etc. The collective results of biochemical and biophysical properties foregrounded their medicinal significance in central nervous system, digestive system, cancer, inflammation, etc. In recent years, new preparative methods for the synthesis of imidazopyridines using various catalysts have been described. The present manuscript to the best of our knowledge is the complete compilation on the synthesis and medicinal aspects of imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines reported from the year 2000 to date, including structure–activity relationships.

Rational drug design and synthesis of molecules targeting the angiotensin II type 1 and type 2 receptors

The angiotensin II (Ang II) type 1 and type 2 receptors (AT1R and AT2R) orchestrate an array of biological processes that regulate human health. Aberrant function of these receptors triggers pathophysiological responses that can ultimately lead to death. Therefore, it is important to design and synthesize compounds that affect beneficially these two receptors. Cardiovascular disease, which is attributed to the overactivation of the vasoactive peptide hormone Αng II, can now be treated with commercial AT1R antagonists. Herein, recent achievements in rational drug design and synthesis of molecules acting on the two AT receptors are reviewed. Quantitative structure activity relationships (QSAR) and molecular modeling on the two receptors aim to assist the search for new active compounds. As AT1R and AT2R are GPCRs and drug action is localized in the transmembrane region the role of membrane bilayers is exploited. The future perspectives in this field are outlined. Tremendous progress in the field is expected if the two receptors are crystallized, as this will assist the structure based screening of the chemical space and lead to new potent therapeutic agents in cardiovascular and other diseases.

Molecular Modeling Studies of Thiophenyl C-Aryl Glucoside SGLT2 Inhibitors as Potential Antidiabetic Agents

A QSAR study on thiophenyl derivatives as SGLT2 inhibitors as potential antidiabetic agents was performed with thirty-three compounds. Comparison of the obtained results indicated the superiority of the genetic algorithm over the simulated annealing and stepwise forward-backward variable method for feature selection. The best 2D QSAR model showed satisfactory statistical parameters for the data set (r (2) = 0.8499, q (2) = 0.8267, and pred_r (2) = 0.7729) with four descriptors describing the nature of substituent groups and the environment of the substitution site. Evaluation of the model implied that electron-rich substitution position improves the inhibitory activity. The good predictive 3D-QSAR models by k-nearest neighbor (kNN) method for molecular field analysis (MFA) have cross-validated coefficient q (2) value of 0.7663 and predicted r (2) value of 0.7386. The results have showed that thiophenyl groups are necessary for activity and halogen, bulky, and less bulky groups in thiophenyl nucleus enhanced the biological activity. These studies are promising for the development of novel SGLT2 inhibitor, which may have potent antidiabetic activity.

Molecular Modeling Studies of Substituted 2,4,5-Trisubstituted Triazolinones Aryl and Nonaryl Derivatives as Angiotensin II AT1Receptor Antagonists

The development of new therapies to treat hypertension and cardiovascular diseases. A series of 2,4,5-trisubstituted triazolinones aryl and nonaryl derivatives were subjected toGroup-based QSAR,k-nearest neighbourmolecular field analysis, and pharmacophore mapping. Multiple linear regression (MLR) methodology coupled with feature selection method namely simulated annealing, was applied to derive Group based QSAR models which were further validated for statistical significance and predictive ability by internal and external validation. The best physicochemical descriptors, namely, R1chiV1, R2T_N_O_3, R2chlorines count, R2T_C_N_4, and R2SssNHE index, contribute significantly to the biological activity. The statistically significant best Group-based QSAR model hasr2=0.8357andq2=0.7266with pred_r2=0.8138. The 3D-QSAR studies were performed using the simulated annealing selectionk-nearest neighbormolecular field analysis approach; a leave-one-out cross-validated correlation coefficientq2=0.7461and predicate activity pred_r2=0.7790were obtained. Contour maps using this approach showed that steric, electrostatic, and hydrophobic effects dominantly determine binding affinities. Pharmacophore hypotheses were generated by the mol sign module and found to contain common features like hydrogen bond donor acceptor, donor, positive, negative ionizable, and hydrophobic features. This model can be used for preliminary screening of large number of substituted 3H-1,-2,-4 triazolinone aryl and nonaryl derivatives. The information rendered by 3D-QSAR models may lead to a better understanding of structural requirements of triazolinone aryl and nonaryl derivatives and also aid in designing novel potent antihypertensive molecules.