Presentation Title

Preparation, Characterization, and Antimicrobial Activity of 6-ethoxy-6-phenyl-6H-chromeno[3,4-b]quinoxaline

Faculty Mentor

Dr. Sara Gremillion and Dr. Brandon Quillian

Faculty Mentor Email

sgremillion@georgiasouthern.edu and bquillian@georgiasouthern.edu

Presentation Type and Release Option

Research Poster Presentation with Supplemental Video (File Not Available for Download)

Location

COUR Symposium 2021

Presentation Year

2021

Start Date

4-19-2021 12:00 AM

End Date

April 2021

Abstract

Quinoxalines and chromenones are structural motifs that are often observed in antimicrobial and antitumor active compounds. We have combined both of these motifs in a single molecule called chromenoquinoxalines. We prepared the molecule by first oxidizing 3-hydroxyflavone in ethanol with molecular oxygen and a stoichiometric amount of copper(II) bromide to produce the hemiacetal, 3-hydroxy-2,3-diethoxy-2-phenylchroman-4-one (1), in good yield (83%). Compound 1 was tested in triplicate for antifungal and antibacterial reactivity by a zone inhibition study, which showed no activity. We prepared 6-ethoxy-6-phenyl-6H-chromeno[3,4-b]quinoxaline (2) by reaction of 1 with ortho-phenylenediamine in the presence of copper(II) bromide in tandem reactions: one in molecular oxygen and the other without. The chromenoquinoxalines were isolated in better yield in reactions without oxygen, as the presence of oxygen caused them to degrade to the orange compound, 2-phenylquinoxaline. All compounds were characterized by 1H NMR spectroscopy. This study is in its early stages; however, both the chromenoquinoxaline and the 2-phenylquinoxaline byproduct from this study will be evaluated for antimicrobial activity in the near future. If found to be active, we plan to make a library of these unique compounds to assess their structural activity relationships against bacteria and fungi.

Academic Unit

Department of Chemistry and Biochemistry

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Preparation, Characterization, and Antimicrobial Activity of 6-ethoxy-6-phenyl-6H-chromeno[3,4-b]quinoxaline

COUR Symposium 2021

Quinoxalines and chromenones are structural motifs that are often observed in antimicrobial and antitumor active compounds. We have combined both of these motifs in a single molecule called chromenoquinoxalines. We prepared the molecule by first oxidizing 3-hydroxyflavone in ethanol with molecular oxygen and a stoichiometric amount of copper(II) bromide to produce the hemiacetal, 3-hydroxy-2,3-diethoxy-2-phenylchroman-4-one (1), in good yield (83%). Compound 1 was tested in triplicate for antifungal and antibacterial reactivity by a zone inhibition study, which showed no activity. We prepared 6-ethoxy-6-phenyl-6H-chromeno[3,4-b]quinoxaline (2) by reaction of 1 with ortho-phenylenediamine in the presence of copper(II) bromide in tandem reactions: one in molecular oxygen and the other without. The chromenoquinoxalines were isolated in better yield in reactions without oxygen, as the presence of oxygen caused them to degrade to the orange compound, 2-phenylquinoxaline. All compounds were characterized by 1H NMR spectroscopy. This study is in its early stages; however, both the chromenoquinoxaline and the 2-phenylquinoxaline byproduct from this study will be evaluated for antimicrobial activity in the near future. If found to be active, we plan to make a library of these unique compounds to assess their structural activity relationships against bacteria and fungi.