1: 74 percent / 50 percent aq. HBF4 / Et4N(1+)*BF4(1-) / acetonitrile / electrolysis 2: sodium dithionite / aq. ethanol / reflux View Scheme

tetrafluoroboric acid; tetraethylammonium tetrafluoroborate in acetonitrile electrolysis, examination of presence of o- or p-anisidine, experiments with further 1-arylazo-2-naphthols; Mechanism;