An efficient synthesis of novel ethyl-1,3,4-triphenyl-1H-pyrazolo[3,4-b]pyridine-6-carboxylate products has been achieved via condensation of pyrazole-5-amine derivatives and activated carbonyl groups, in refluxing acetic acid. This process has been found to be useful in the preparation of new N-fused heterocycle products in good to excellent yields.

Background: Hyperglycemia is a metabolic disorder that refers to an increase in blood sugar in diabetic patients. α-Glucosidase has been introduced as a membrane-bound enzyme, and it is the main enzyme for carbohydrate digestion in some parts of the intestine. Inhibition of α -glucosidase enzyme activity is a reliable approach to control post-prandial hyperglycemia condition. Objectives: In this study, a series of Pyrazolo[1,2-b]phthalazine-5,10-dione derivatives 5a–t were synthesized via a multicomponent reaction and evaluated as new inhibitors for α-glucosidase. Methods: The biological activity of the synthesized compounds was studied using a source of the α-glucosidase enzyme (EC3.2.1.20, Saccharomyces cerevisiae) at 20 U/mg concentration. Results: Four compounds showed higher α-glucosidase inhibitory activity in comparison to a standard, i.e., Acarbose. Compound 5q displays the most potent α-glucosidase inhibitory activity (IC50 = 155.4 ± 6.0 μM). Conclusion: In conclusion, some of the synthesized compounds, including heterocyclic core molecules, have shown remarkable activity that could be considered as subjects for the development of new, more efficient inhibitors of the α-glucosidase enzyme.

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Groups. -(GHAEDI, A.; BARDAJEE*, G. R.; MIRSHOKRAYI, A.; MAHDAVI, M.; SHAFIEE, A.; AKBARZADEH, T.; RSC Adv. 5 (2015) 109, 89652-89658, http://dx.