SnCl2(Ber.,21,3471)
5g ofbeta-aminonaphtol orange are dissolved in 50ml of H2O. To the boiling orange liquid is added a solution of 12g of SnCl2 in 30ml HCl(d=1,19). With a vigorous reaction the mixture start to loose color. After some minutes it is completely colorless. The reaction mixture is cooled to precipitate the aminonaphtol hydrchloride, wich is filtered, washed with dillute HCl, alcohol and, finally, ether.
beta-aminonaphtol is separated from the aqueous solution of the hydrochloride by addition of sodium acetate in the form of needles.
With oxidants like chromic acid beta-naphtoquinoe is formed(Ber.,XXVII,3076).
Sodium Bissulfite(Ber.,39,3561)
To a hot solution of 5g beta-naphtol orange in 50ml H2O, concentrated sodium bissulfite solution is added, in small amounts, until the orange/red liquid is almost completely colorless. Slightly colored beta-aminonaphtol precipitates. According to the purity of the sodium bissulfite, 5 to 10g are used. After cooling, the formed aminonaphtol is separated by filtration, washed with water, and dried in plate of pourous pot.
The workup might need some changes if the properties of 3,4-dihydroxyaniline differ from the substance they get. Maybe not, i don´t know.