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oai:ojs.www.eurjchem.com:article/1792 2018-12-31T07:23:25Z eurjchem:ART driver

Synthesis and characterization of new 4-aryl-2-(2-oxopropoxy)-6-(2,5-dichlorothiophene)nicotinonitrile and their furo[2,3-b]pyridine derivatives: Assessment of antioxidant and biological activity Al‐Refai, Mahmoud Ibrahim, Mohammad Al‐Fawwaz, Abdullah Geyer, Armin Pyridine Thiophene Antioxidant Nicotinonitrile Cyanopyridone Furo[2 3-b]pyridine A new series of furo[2,3-b]pyridine derivatives bearing aryl substituents were synthesized in two steps, where, the cyano-(2H)-pyridones (1a-l) were converted to the corresponding nicotinonitriles (2a-l), followed by the Thorpe-Ziegler ring cyclization to the furo[2,3-b]pyridine derivatives (3a-l). All new compounds were characterized by 1D-NMR experiments (1H and 13C) and 2D-NMR experiments (COSY, HMBC and HSQC), as well as ESI-MS and HR-ESI-MS data. The new compounds were screened for their antioxidant activities by 2,2-diphenyl-1-picryl-hydrazylhydrate (DPPH) free radical assay. The highest radical scavenging effect was observed for nicotinonitriles 2d, 2h and 2l and furo[2,3-b]pyridines 3b, 3f and 3j by methanolic solvent at 4.0 mg/mL concentration. Remarkably, all nicotinonitriles and furo[2,3-b]pyridine exhibited a significant radical scavenging activity after 24 and 48 hours compared with 0.5 hour. Atlanta Publishing House LLC 2018-12-31 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion application/pdf https://www.eurjchem.com/index.php/eurjchem/article/view/1792 10.5155/eurjchem.9.4.375-381.1792 European Journal of Chemistry; Vol. 9 No. 4 (2018): December 2018; 375-381 2153-2257 2153-2249 eng https://www.eurjchem.com/index.php/eurjchem/article/view/1792/pdf_1792 Copyright (c) 2018 Authors