Microwave‐Assisted Synthesis of Bis(enaminoketones): Versatile Precursors for Novel Bis(pyrazoles) via Regioselective 1,3‐Dipolar Cycloaddition with Nitrileimines |
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| Authors: | Ahmed H. M. Elwahy Ahmed F. Darweesh Mohamed R. Shaaban |
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| Affiliation: | 1. Department of Chemistry, Faculty of Science, Cairo University, Giza, Egypt;2. Department of Chemistry, Faculty of Applied Science, Umm Al‐Qura University, Makkah Almukkarramah, Saudi Arabia |
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| Abstract: | Synthesis of bis(enaminones) 6a , 6b , 6c and 7a , 7b , 7c was accomplished by the reaction of bis(acetophenones) 3a , 3b , 3c and 4a , 4b , 4c with dimethylformamide–dimethylacetal, under microwave irradiation. 1,3‐Dipolar cycloaddition of bis(enaminones) 6a and 7b , 7c with nitrileimines in refluxing benzene led to the regioselective synthesis of the novel bis(pyrazoles) 11a , 11b , 11c , 11d , 11e , 11f , 11g , 11h in 62–89% yield. The bis(pyrazoles) 11b , 11c underwent condensation with hydrazine hydrate to give the corresponding bis(pyrazolo[3,4‐d]pyridazines) 14a , 14b in good yields. |
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