Pyrazole scaffold-based derivatives: A glimpse of α-glucosidase inhibitory activity, SAR, and route of synthesis

The α-glucosidase is a validated target to develop drugs for treating type 2 diabetes mellitus. The existing α-glucosidase inhibitors have certain shortcomings related to side effects and route of synthesis. Accordingly, it is inevitable to develop new chemical templates as α-glucosidase inhibitors. Pyrazole derivatives have a special place in medicinal chemistry because of various biological activities. Recently, pyrazole-based heterocyclic compounds have emerged as a promising scaffold to develop α-glucosidase inhibitors. This study focuses on the recently reported pyrazole-based α-glucosidase inhibitors, including their biological activity (in vivo, in vitro, and in silico), structure-activity relationship, and ways of synthesis. The literature revealed the development of several promising pyrazole-based α-glucosidase inhibitors and new synthetic routes for their preparation. The encouraging α-glucosidase inhibitory results of the pyrazole-based heterocyclic compounds make them an attractive target for further research. The authors also foresee the arrival of the pyrazole-based α-glucosidase inhibitors in clinical practice.

Recent Advances in Synthesis and Properties of Pyrazoles

Pyrazole-containing compounds represent one of the most influential families of N-heterocycles due to their proven applicability and versatility as synthetic intermediates in preparing relevant chemicals in biological, physical-chemical, material science, and industrial fields. Therefore, synthesizing structurally diverse pyrazole derivatives is highly desirable, and various researchers continue to focus on preparing this functional scaffold and finding new and improved applications; this review highlights some of the most recent and strategic examples regarding the synthesis and properties of different pyrazole derivatives, mainly reported from 2017–present. The discussion involves strategically functionalized rings (i.e., amines, carbaldehydes, halides, etc.) and their use in forming various fused systems, predominantly bicyclic cores with 5:6 fusion taking advantage of our experience in this field and the more recent investigations of our research group.

A Review of the Recent Development in the Synthesis and Biological Evaluations of Pyrazole Derivatives

Pyrazoles are five-membered heterocyclic compounds that contain nitrogen. They are an important class of compounds for drug development; thus, they have attracted much attention. In the meantime, pyrazole derivatives have been synthesized as target structures and have demonstrated numerous biological activities such as antituberculosis, antimicrobial, antifungal, and anti-inflammatory. This review summarizes the results of published research on pyrazole derivatives synthesis and biological activities. The published research works on pyrazole derivatives synthesis and biological activities between January 2018 and December 2021 were retrieved from the Scopus database and reviewed accordingly.

Synthesis of 4-alkylaminoimidazo[1,2-a]pyridines linked to carbamate moiety as potent α-glucosidase inhibitors

In this work, various imidazo[1,2-a]pyridines linked to carbamate moiety were designed, synthesized, and evaluated for their α-glucosidase inhibitory activity. Among synthesized compounds, 4-(3-(tert-Butylamino)imidazo[1,2-a]pyridin-2-yl)phenyl p-tolylcarbamate (6d) was the most potent compound (IC50 = 75.6 µM) compared with acarbose as the reference drug (IC50 = 750.0 µM). Kinetic study of compound 6d indicated a competitive inhibition. Also, the molecular docking study suggested desired interactions with the active site residues. In particular, hydrogen bonds and electrostatic interactions constructed by compound 6d afforded well-oriented conformation in the 3A4A active site.

Design and Synthesis of Novel 5-Arylisoxazole-1,3,4-thiadiazole Hybrids as α-Glucosidase Inhibitors

Background:

α-Glucosidase inhibitors have occupied a significant position in the treatment of type 2 diabetes. In this respect, the development of novel and efficient non-sugar-based inhibitors is in high demand.

Objective:

Design and synthesis of new 5-arylisoxazole-1,3,4-thiadiazole hybrids possessing α- glucosidase inhibitory activity were developed.

Methods:

Different derivatives were synthesized by the reaction of various 5-arylisoxazole-3- carboxylic acids and ethyl 2-((5-amino-1,3,4-thiadiazol-2-yl)thio)acetate. Finally, they were evaluated for their α-glucosidase inhibitory activity.

Results:

It was found that ethyl 2-((5-(5-(2-chlorophenyl)isoxazole-3-carboxamido)-1,3,4-thiadiazol- 2-yl)thio)acetate (5j) was the most potent compound (IC50 = 180.1 μM) compared with acarbose as the reference drug (IC50 = 750.0 μM). Also, the kinetic study of 5j revealed a competitive inhibition and docking study results indicated desired interactions of that compound with amino acid residues located close to the active site of α-glucosidase.

Conclusion:

Good α-glucosidase inhibitory activity obtained by the title compounds introduced them as an efficient scaffold, which merits to be considered in anti-diabetic drug discovery developments.

Celebrex derivatives: Synthesis, α-glucosidase inhibition, crystal structures and molecular docking studies

Celebrex (1), commonly used as an anti-inflammatory drug, was functionalized (compounds 2-9) to identify new α-glucosidase inhibitors. Initially, all the synthesized derivatives were evaluated for anti-inflammatory activity but none was found to be active. Subsequently a random biological screening was carried out. Interestingly many of them were found to be potent α-glucosidase inhibitors in vitro. All the structures of synthesized derivatives were deduced through ¹H NMR, FAB-MS, HR-MS, FT-IR analysis. The single-crystal X-ray structures of compounds 1, and 5 further confirmed the assigned structures. Compounds exhibited a potent α-glucosidase inhibitory activity (IC₅₀ = 92.32 ± 1.530-445.20 ± 1.04 µM) against tested standard acarbose (IC₅₀ = 875.75 ± 2.08 µM), except compounds 2 and 4, which appeared as inactive. Among them, compound 9 (IC₅₀ = 92.32 ± 1.530 µM) was the most potent inhibitor of α-glucosidase enzyme. Molecular docking studies revealed that compounds 6, and 9 interacted with the key amino acid residues of α-glucosidase via H-bonding, and π-π stacking interactions. α-Glucosidase is a key target for the anti-diabetic drug development, and its inhibitors are known to exert anti hyperglycemic effect and help in lowering of post-prandial blood glucose levels.