CYCLIZATION OF N-ALKYLAZINIUM CATIONS WITH BIFUNCTIONAL NUCLEOPHILES. 16. ?-ADDUCTS OF QUINOXALINIUM SALTS WITH AMINES, ALCOHOLS, AND ENOLATES AND THEIR ROLE IN CYCLIZATIONS WITH β-DICARBONYL COMPOUNDS

Article abstract of DOI:10.1007/BF00506075

In the reaction of N-methylquinoxalinium iodide with acetylacetone at -30 deg C, the formation of 3-acetyl-2,4-dimethyl-3a,4,9,9a-tetrahydrofuro<2,3-b>quinoxaline has been recorded by 1H NMR spectroscopy, this being a regioisomer of the 3-acetyl-2,9-dimethyl-3a,4,9,9a-tetrahydrofuro<2,3-b>quinoxaline formed in this reaction at temperatures above -10 deg C. ?-Adducts of the N-methylquinoxalinium cation with alcohols, amines, and β-diketones have also been identified, and their role in cyclizations leading to the annelation of a furan ring is discussed.