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Synthesis of New Isoxazole-, Pyridazine-, Pyrimidopyrazines and Their Anti-Inflammatory and Analgesic Activity

[ Vol. 14 , Issue. 4 ]


Ameen A. Abu-Hashem* and Mohamed El-Shazly   Pages 356 - 371 ( 16 )


Background: Isoxazoles, pyridazines, and pyrimidopyrazines have recently attracted attention due to their potent pharmacological activities. They exhibited anticancer, neuroprotective, analgesic and anti-inflammatory effects.

Objective: The study aimed to synthesize novel isoxazoles, pyridazines, and pyrimidopyrazines through efficient high yield protocol for evaluating their analgesics and anti-inflammatory activities.

Method: A series of novel isoxazole-, pyridazine-, pyrimidopyrazine derivatives was prepared from 5,8-alkyl-1,3-dimethyl-5,6-dihydropyrimido[5,6-e]pyrazine-2,4,7-trione (1a,b) as the starting material.

Results: The prepared derivatives were synthesized in moderate to good yields (60-75%) in a stepwise efficient protocol under mild condition. These new compounds have been proven by several spectroscopic techniques as IR, 1D and 2D NMR techniques and mass analysis. The in vivo anti-inflammatory was assessed for the synthesized compounds using carrageenan-induced rat hind paw edema model. Also, the in vivo analgesic activity for these products was examined utilizing hot-plate and acetic acid-induced writhing response assays.

Conclusion: The isoxazole derivatives (3a-f) showed the most forceful anti-inflammatory and analgesic activities. Pyrimidopyrazines (4a-f) demonstrated weaker but comparable antiinflammatory and analgesic activities to the positive controls.


Analgesic activity, anti-inflammatory, isoxazole, pyrazine, pyridazine, pyrimidine.


Photochemistry Department (Heterocyclic Unit), National Research Centre, 12622 Dokki, Giza, Department of Pharmaceutical Biology, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo 11432

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