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

Abstract

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.

Reduction of nitroarenes followed by propanol group transfer from tris(3‐hydroxypropyl)‐ amine and cyclization leading to quinolines under heterogeneous PdC catalysis

“…Removal of the solvent left a crude mixture, which was separated by thin‐layer chromatography (silica gel, ethyl acetate–hexane mixture) to give quinoline ( 3a ) (0.132 g, 102%). Except for new compound 3l , which was characterized spectroscopically as shown below, all quinolines were characterized by GLC and/or spectroscopic comparision with authentic samples synthesized by known methods 25–29…”