Ruthenium-catalyzed synthesis of quinolines via reductive heteroannulation of nitroarenes with 3-amino-1-propanols

Nitroarenes are reductively cyclized with 3-amino-1-propanols in dioxane/H₂O in the presence of a ruthenium catalyst and tin(II) chloride dihydrate together with isopropanol to afford the corresponding quinolines. A reaction pathway involving initial reduction of nitroarenes to anilines, propanol group transfer from 3-amino-1-propanols to anilines, N-alkylation of anilines by 3-anilino-1-propanols and heteroannulation of 1, 3-dianilinopropanes is proposed.