Condensation reactions of dialkoxy-2-phenylchroman-4-ones with 1,2-diamines: A method for the preparation of chromenoquinoxalines

Hannah Watkins, Gerald Lee, Pangbewindin H.B. Ouedraogo, Clifford W. Padgett, Khoa Nguyen, Rylan Artis, Brandon P. Quillian

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Reactions of dialkoxy-2-phenylchroman-4-ones (2,3-diethoxy-3-hydroxy-2-phenylchroman-4-one (1) and 2,3-dimethoxy-3-hydroxy-2-phenylchroman-4-one (2)) with various phenylenediamines in refluxing chloroform led to quinoxaline ring formation to produce racemic mixtures of chromenoquinoxaline molecules in good to moderate yields (3–10). The proposed mechanism involves the hemiacetals (1 and 2) rearranging upon heating to form a reactive dione intermediate that subsequently reacts with phenylenediamine derivatives to produce the title compounds. Reactions of 1 and 2 with asymmetric phenylenediamines led to mixtures of two regioisomers, for which the major products were dictated by the relative reactivity of the nucleophilic amine and the electrophilic carbonyl groups. The chromenoquinoxaline products were characterized by 1H, 13C, 19F (when necessary), nuclear magnetic resonance spectroscopy, high-resolution mass spectrometry, melting point determination, and in some cases (compounds 6–10) single crystal X-ray diffraction studies. Herein, the synthesis, characterization, and reactivity of this new class of molecules are discussed.

Original languageEnglish
Article number154820
JournalTetrahedron Letters
Volume132
DOIs
StatePublished - Nov 30 2023

Scopus Subject Areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

Keywords

  • Chromane
  • Chromenoquinoxaline
  • Condensation
  • Diamine
  • Dicarbonyl
  • Dione intermediate
  • Hemiacetal
  • Quinoxaline

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