NEW METHOD OF SYNTHESIS OF QUINDOLINES FROM 1,5-DIKETONES OF THE INDOLINONE SERIES

Article abstract of DOI:10.1007/BF00505963

By the action of ammonium acetate and α,β-unsaturated carbonyl compounds, 1,5-diketones of the indolinone series undergo not yet known transformations into difficulty accessible 1,2-dihydro-10H-quindolines.Under these conditions, 11-phenyl-1,2,3,4-tetrahydro-10H-quindoline was obtained from 1-acetyl-2-(benzylcyclohexan-1-on-α-yl)indolin-3-one.Dihydroquindolines with identical aryl substituents in the 1- and 11-positions were obtained from 1-acetylindolin-3-one by the action of an excess of certain α,β-unsaturated ketones and ammonium acetate.Dehydrogenation ofdihydroquindolines proceeds smoothly on heating with sulfur.The possible paths of the formation of dihydroquindolines are discussed.