Synthesis and in vitro evaluation of dihydro-6H-chromeno[4,3-b]isoxazolo[4,5-e]pyridine derivatives as potent antidiabetic agents

Pharmacochemical Studies of Synthesized Coumarin-Isoxazole-Pyridine Hybrids

Several new coumarin-isoxazole-pyridine hybrids were synthesized through a 1,3-dipolar cycloaddition reaction of nitrile oxides, prepared in situ from pyridine aldehyde oximes, with propargyloxy- or propargylaminocoumarins in moderate-to-good yields. Synthetic modifications were applied using (diacetoxyiodo)benzene (PIDA) at room temperature, microwave irradiation, or tert-butyl nitrite (TBN) under reflux. Coumarin, isoxazole, and pyridine groups were selected for hybridization in one molecule due to their biological impact to inhibit lipid peroxidation and an enzyme implicated in inflammation. Preliminary in vitro screening tests for lipoxygenase (LOX) inhibition and anti-lipid peroxidation for the new hybrids were performed. A discussion on the structure-activity relationship is presented. Compounds 12b and 13a were found to be potent LOX inhibitors with IC50 5 μΜ and 10 μΜ, respectively, while 12b presented high (90.4%) anti-lipid peroxidation. Furthermore, hybrids 12b and 13a exhibited moderate-to-low anticancer activities on HeLa, HT-29, and H1437 cancer cells.

Iodine-Catalyzed Diversity-Oriented Synthesis of 3,4-Heterocycle-Fused Coumarins from 4-Aminocoumarins and Aurones in Different Solvent

An unprecedented protocol has been developed for the synthesis of 3,4-heterocycle-fused coumarins from 4-aminocoumarins and aurones through iodine-catalyzed cascade reactions. Dihydropyridine-fused coumarin, pyridine-fused coumarin, and pyrrole-fused coumarin derivatives were achieved in good yields with high selectivity when CH3CN, AcOH, and DMSO were used as the solvent, respectively. This protocol provides several advantages, such as easily available starting materials, high atom economy, friendly environment, and simple procedure.

Regioselective syntheses of 2-oxopyridine carbonitrile derivatives and evaluation for antihyperglycemic and antioxidant potential

A library of 2-oxopyridine carbonitriles 1-34 was synthesized by regioselective nucleophilic substitution reactions. In the first step, a one-pot multicomponent reaction yield pyridone intermediates. The resulting pyridone intermediates were then reacted with phenacyl halides in DMF and stirred at 100 °C for an hour to afford the desired compounds in good yields. Structures of synthetic molecules were characterized by EI-MS, HREI-MS, ¹H NMR, and ¹³C NMR, and all thirty-four (34) compounds were found to be new. All synthetic compounds were examined for antidiabetic and antioxidant potential. The compounds exhibited α-glucosidase inhibitory potential in the range of IC₅₀ = 3.00 ± 0.11-43.35 ± 0.67 μM and α-amylase inhibition potential in the range of IC₅₀ = 9.20 ± 0.14-65.56 ± 1.05 μM. Among the tested compounds, 1 showed the most significant α-glucosidase inhibitory activity, with an IC₅₀ value of 3.00 ± 0.11 μM, while the most active compound against α-amylase was 6, with an IC₅₀ value = 9.20 ± 0.14 μM. The kinetic studies and analysis indicated that the compounds followed the competitive mode of inhibition. In addition, the molecular docking studies showed the interaction profile of all molecules with the binding site residues of α-glucosidase and α-amylase enzymes.

Pyridine: the scaffolds with significant clinical diversity

The nitrogen-bearing heterocycle pyridine in its several analogous forms occupies an important position as a precious source of clinically useful agents in the field of medicinal chemistry research. This privileged scaffold has been consistently incorporated in a diverse range of drug candidates approved by the FDA (Food and Drug Administration). This moiety has attracted increasing attention from several disease states owing to its ease of parallelization and testing potential pertaining to the chemical space. In the next few years, a larger share of novel pyridine-based drug candidates is expected. This review unifies the current advances in novel pyridine-based molecular frameworks and their unique clinical relevance as reported over the last two decades. It highlights an inclination to the use of pyridine-based molecules in drug crafting and the subsequent emergence of several potent and eligible candidates against a range of diversified diseases.

The nitrogen-bearing heterocycle pyridine in its several analogous forms occupies an important position as a precious source of clinically useful agents in the field of medicinal chemistry research.