Synthesis and electrophilic substitutions of novel pyrazolo[1,5-c]-1,2,4-triazolo[4,3-a]pyrimidines |
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Authors: | Atta Kamal F M |
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Institution: | Chemistry Department, Faculty of Science, Alexandria University, Ibrahimia P.O. Box 426, Alexandria 21321, Egypt. prof.kf_atta@yahoo.com |
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Abstract: | 5-Aryl-7-hydrazino-2-phenylpyrazolo1,5-c]pyrimidines 1 were used as precursors for the preparation of a new series of 5-aryl-8-phenylpyrazolo1,5-c]-1,2,4- triazolo4,3-a]pyrimidines 2. The reactions of 2 with certain electrophilic reagents gave the respective 6-substituted derivatives 3-5 rather than the 7-isomeric products. Formylation of the key compounds 1 with ethyl formate yielded the formyl derivatives 6. Furthermore, boiling of compounds 1 with acetic acid afforded 7-acetylhydrazino-5-aryl-2-phenylpyrazolo1,5-c]pyrimidines 7. Bromination of 7 yielded the dibromo- derivatives 8, while their iodination and nitration gave the monosubstituted derivatives 9 and 10, respectively. Also, treatment of 1 with boiling acetic anhydride yielded the triacetyl derivatives 11. The structure of synthesized products was confirmed by elemental analyses, IR, 1H NMR and MS spectra. |
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