Ruthenium-catalyzed synthesis of indoles from anilines and trialkanolammonium chlorides in an aqueous medium

Anilines react with trialkanolammonium chlorides in an aqueous medium (H2O–dioxane) at 180°C in the presence of a catalytic amount of ruthenium(III) chloride hydrate and triphenylphosphine together with tin(II) chloride dihydrate to afford the corresponding indoles in good yields.