Novel analogs of quinoline and isoindoline containing various heterocycles, such as tetrazole, triazole, pyrazole, and pyridine, were synthesized and characterized using FT-IR, NMR, and mass spectroscopy, and their antioxidant and antidiabetic activities were investigated. The previously synthesized compound 1 was utilized in conjugation with ketone-bearing tetrazole and isoindoline-1,3-dione to synthesize Schiff’s bases 2 and 3. Furthermore, hydrazide 1 was treated with aryledines to provide pyrazoles 4a–c. Compound 5 was obtained by treating 1 with potassium thiocyanate, which was then cyclized in a basic solution to afford triazole 6. On the other hand, pyridine derivatives 7a–d and 8a–d were synthesized using 2-(4-acetylphenyl)isoindoline-1,3-dione via a one-pot condensation reaction with aryl aldehydes and active methylene compounds. From the antioxidant and antidiabetic studies, compound 7d showed significant antioxidant activity with an EC₅₀ = 0.65, 0.52, and 0.93 mM in the free radical scavenging assays (DPPH, ABTS, and superoxide anion radicals). It also displayed noteworthy inhibitory activity against both enzymes α-glycosidase (IC₅₀: 0.07 mM) and α-amylase (0.21 mM) compared to acarbose (0.09 mM α-glycosidase and 0.25 mM for α-amylase), and higher than in the other compounds. During in silico assays, compound 7d exhibited favorable binding affinities towards both α-glycosidase (−10.9 kcal/mol) and α-amylase (−9.0 kcal/mol) compared to acarbose (−8.6 kcal/mol for α-glycosidase and −6.0 kcal/mol for α-amylase). The stability of 7d was demonstrated by molecular dynamics simulations and estimations of the binding free energy throughout the simulation session (100 ns).

Background: Type 2 diabetes has become a significant global health challenge. Numerous drugs have been developed to treat the condition, either as standalone therapies or in combination when glycemic control cannot be achieved with a single medication. As existing treatments often come with limitations, there is an increasing focus on creating novel therapeutic agents that offer greater efficacy and fewer side effects to better address this widespread issue. Methods: The methylene derivatives 3a,b were coupled with phenyl/ethyl isothiocyanate in the basic medium, and dimethyl sulfate was subsequently added. Further, 5a–d were reacted with the quinoline/naphthalene hydrazides 6a,b. The target compounds 7a–g were subjected to the in vitro enzyme inhibition studies on α-glucosidase, α-amylase, and aldose reductase. Results: 7g exerted remarkable inhibitory effects on α-glycosidase [Inhibitory Concentration (IC₅₀): 20.23 ± 1.10 µg/mL] and α-amylase (17.15 ± 0.30 µg/mL), outperforming acarbose (28.12 ± 0.20 µg/mL for α-glycosidase and 25.42 ± 0.10 µg/mL for α-amylase), and exhibited a strong inhibition action on aldose reductase (12.15 ± 0.24 µg/mL), surpassing quercetin (15.45 ± 0.32 µg/mL) and the other tested compounds. In a computational study, 7g demonstrated promising binding affinities (−8.80, −8.91 kcal/mol) with α-glycosidase and α-amylase, compared to acarbose (−10.87, −10.38 kcal/mol) for α-glycosidase and α-amylase. Additionally, 7g had strong binding with aldose reductase (−9.20 kcal/mol) in comparison to quercetin (−9.95 kcal/mol). Molecular dynamics (MDs) simulations demonstrated that 7g remained stable over a 100 ns simulation period, and the binding free energy estimates remained consistent throughout this time. Conclusions: We reported the modification of quinoline and naphthalene rings to hydrazineylidene–propenamides 7a–g using various synthetic approaches. 7g emerged as a leading candidate, exhibiting greater inhibition of α-glycosidase, α-amylase, and aldose reductase. These findings underscore their potential as essential molecules for the development of innovative antidiabetic treatments.

Novel families of thiazolidine-2,4-dione and imidazolidine-2,4-dione derivatives were synthesized. Thiazolidine-2,4-dione 3 was prepared using chloroacetic acid and thiourea, followed by condensation with terephthalaldehyde to form 4-((2,4-dioxothiazolidine-5-ylidene)methyl)benzaldehyde 4. This compound reacted with 2-aryloxyacetohydrazides 8a-b to yield Schiff bases 9a-b. Imidazolidine-2,4-diones 13a-c were synthesized via cyclizing of anilines 10a-c, urea 11, and chloroacetic acid 12. The compounds 9a-b and 13a-c were evaluated for antitumor activity against the Caco-2 cell line, compounds 13b and 13c exhibiting the highest potency (IC50 values of 41.30 ± 0.07 μM and 109.2 ± 0.027 μM, respectively). DFT calculations, including HOMO-LUMO analysis, energy gap estimation, and molecular docking, were conducted to evaluate and optimize the molecular properties of the target compounds.