1-Naphthol

1-Naphthol is prepared by two main routes. In one method, naphthalene is nitrated to give 1-nitronaphthalene, which is hydrogenated to the amine followed by hydrolysis: : : : Alternatively, naphthalene is hydrogenated to tetralin, which is oxidized to 1-tetralone, which undergoes dehydrogenation. ==Reactions==

Some reactions of 1-naphthol are explicable with reference to its tautomerism, which produces a small amount of the keto tautomer. : One consequence of this tautomerism is the Bucherer reaction: the ammonolysis of 1-naphthol to give 1-aminonaphthalene. Low temperature sulfonation of 1-naphthol gives 1-hydroxynaphthalene-2-sulfonic acid. 1-Naphthol biodegrades via formation of 1-naphthol-3,4-oxide, which converts to 1,4-naphthoquinone. The 4-position of 1-naphthol is susceptible to electrophilic attack. This regioselective reaction is exploited in the preparation of diazo dyes, which are form using diazonium salts. Reduction of the diazo derivatives gives 4-amino-1-naphthol. Partial reduction of 1-naphthol gives the tetrahydro derivative, leaving intact the phenol ring. Full hydrogenation is catalyzed by rhodium. ==Applications and occurrence==

1-Naphthol is a precursor to a variety of insecticides including carbaryl and pharmaceuticals including nadolol and the anti-protozoan therapeutic atovaquone. It undergoes azo coupling to give various azo dyes, but these are generally less useful than those derived from 2-naphthol. 1-Naphthol is a metabolite of the insecticide carbaryl and naphthalene. Along with TCPy, it has been shown to decrease testosterone levels in adult men. An agent called SBFI-26 is an ester that is formed between 1-naphthol and truxillic acid. Other uses 1-Naphthol is used in each of the following chemical tests, which predate the use of spectroscopic and chromatographic methods: • Molisch's test gives a red- or purple-colored compound to indicate the presence of carbohydrate. • rapid furfural test turns purple quickly (<30s) if fructose is present, distinguishing it from glucose. • Sakaguchi test turns red to indicate the presence of arginine in proteins. • Voges–Proskauer test changes color from yellow to red to indicate that glucose is being broken down into acetoin which is used by bacteria for external energy storage. ==Safety==

1-Naphthol has been described as "moderately toxic". ==References==