Ionic liquids as novel and recyclable reaction media for N-alkylation of amino-9,10-anthraquinones by trialkyl phosphites

Ionic liquids such as 1,3-dialkylimidazolium bromides make excellent catalysts and solvents for N-alkylation of amino-9,10-anthraquinones in the presence of trialkyl phosphites. For triethyl phosphite, [bpim][Br] gave better results. The ionic liquids are successfully regenerated and reused.