A New Method for the Synthesis of 2-Hydroxy-3-nitro-1,4-naphthoquinones:  Application to Regiospecific Preparation of Unsymmetrical Nitrobiquinones

Novel 2-hydroxy-3-nitro-1,4-naphthoquinones were synthesized by an improved method utilizing nitronium tetrafluoroborate in high yields. A subsequent conversion to 2-chloro-3-nitro-1,4-naphthoquinones and a substitution of the chlorine by hydroxyquinone anions yielded 3-nitro-2,2'-binaphthoquinones with a complete regiocontrol.