Efficient synthesis,reactions, and biological activities of new thieno and furopyrazolo[3,4-b]pyrazines and their related heterocycles |
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Authors: | Remon M Zaki Adel M Kamal El-Dean Shaban M Radwan Mokhtar A Abd ul-Malik |
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Institution: | 1. Chemistry Department, Faculty of Science, Assiut University, Assiut, Egypt;2. Chemistry Department, Faculty of Science, Assiut University, Assiut, Egypt
Chemistry Department, Faculty of Science, Taiz University, Taiz, Yemen |
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Abstract: | In the present investigation, a simple and straightforward methodology for the preparation of novel bifunctional thienopyrazolopyrazines 4a–d has been reported. Synthesis of thieno or furopyrazolopyrazines 5a , b , e , f was achieved by the reaction of o-amino-esters 4a , b , e , f with 2,5-dimethoxytetrahydrofuran. The latter pyrrolyl derivatives 5a , b , e , f were used as starting intermediates for the synthesis of new pyrimido, pyrido, and pyrazino heterocycles fused to the thieno or furopyrazolopyrazine moiety. Furthermore, alkaline hydrolysis of the o-amino-ester 4a followed by acidification afforded the corresponding o-amino carboxylic acid 15 , which was used as a versatile precursor for the synthesis of other heterocyclic compounds fused to the thienopyrazolopyrazine ring system, namely: pyrimidine, oxazine, oxazepine, and pyridine derivatives 16–23 . The chemical structures of the synthesized compounds were confirmed on the basis of elemental and spectral analyses (Fourier-transform infrared spectroscopy FT-IR], 1H nuclear magnetic resonance NMR], and mass spectroscopy MS] in addition to 13C NMR for some of them). Moreover, from the biological screening, we found that most of the tested compounds exhibited promising antifungal, antibacterial, and anti-inflammatory activities compared with the corresponding reference drugs. |
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Keywords: | anti-inflammatory activity antimicrobial activity pyrazolo[3 4-b]pyrazine synthesis thienopyrazolopyrazine |
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