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Abstract
A convenient synthetic approach leading to a series of novel substituted azoles, azines, and azepines linked to the α-aminophosphonate moiety was achieved. The methodology depends on ring opening and ring closure (RORC) of the chromone ring of diethyl chromonyl α-aminophosphonate 1 via its reaction with nitrogen nucleophiles such as primary amines and 1,2-, 1,3-, and 1,4-bi-nucleophiles in ethanolic sodium ethoxide. Also, treatment of compound 1 with some acyclic and cyclic active methylene compounds under the same reaction conditions afforded interesting novel isolated and fused pyridine systems bearing phosphonate groups at the α-position. The screening of antimicrobial activity for the synthesized compounds indicates that connection of pyrazole, oxazepine, and benzodiazepine rings with α-aminophosphonate moiety exhibited good antimicrobial effects. Also, evaluation of their antioxidant properties shows that the compounds having 1,5-benzoxazepinyl and 1,5-benzodiazepinyl units in combination with α-aminophosphonic diester moiety are the most powerful antioxidant agents.
GRAPHICAL ABSTRACT
ACKNOWLEDGMENTS
The authors are very grateful to the Department of Microbiology, Faculty of Agriculture, Al‐Azhar University for Girls, Nasr‐City, Cairo, Egypt, for performing the antimicrobial evaluation and to Engy Mahmoud for evaluation of the antioxidant properties in Department of Flavour and Aroma Chemistry, National Research Center (NRC), Egypt.
Notes
a Low activity: 6–12 mm; moderate activity: 13–19 mm; high activity: 20–30 mm. Dash (—) denotes no inhibition or inhibition less than 5 mm.
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