Synthesis of Vitamin Quinones

Prelab Exercise Write balanced equations for the reduction of Orange II to aminonaphthol with sodium hydrosulfite and for the oxidation of aminonaphthol to 1,2-naphthoquinone using ferric chloride. 

In the first experiment of this chapter the dye Orange II is reduced in aqueous solution with sodium hydrosulfite to water-soluble sodium sulfa-nilate and l-amino-2-naphthol (2), which precipitates. This intermediate is purified as the hydrochloride and oxidized to 1,2-naphthoquinone (3). 

The experiments of this chapter are a sequence of steps for the synthesis of the antihemorrhagic vitamin Kj (or an analog) starting with a coal-tar hydrocarbon. 

2-Methylnaphthalene (1) is oxidized with chromic acid to 2-methyl-1,4-naphthoquinone (5) the yellow quinone is purified and reduced to its hydroquinone (6) by shaking an ethereal solution of the substance with aqueous hydrosulfite solution the colorless hydroquinone is condensed with phytol and the substituted hydroquinone (7) is oxidized to vitamin K, (9). 

Caution Contact of solid sodium hydrosulfite with moist combustible material may cause a fire. 

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