Beirut reaction and its application in the synthesis of quinoxaline-N,N'-dioxides bioactive compounds

Abstract

Described by Haddadin and Issidorides in 1965, the cycloaddition between benzofuroxan (i.e. benzofurazan oxide or 2,1,3-benzoxadiazole-1-oxide) with enamines, αβ-unsaturated ketones, 1,3-dinitriles, or enolates to produce quinoxaline-N-,N'-dioxides is referred in chemical literature as the Beirut reaction. The feasibility to synthesize, in a single step, heterocyclic aromatic amine oxides with different levels of functionalization makes the Beirut reaction a central tool for synthesize compounds with several industrial applications, like carbadox, cyadox and olaquindox, that became available as antimicrobial growth promoters in food animal production, allowing the identification of quinoxaline-N,N'-dioxides system as an important scaffold for obtaining new bioactive compounds.