Naphthoquinones, halogenated

Uses Intermediate for phthalic anhydride, naphthol, 1,4-naphthoquinone, 1,4-dihydro-naphthalene, 1,2,3,4-tetrahydronaphthalene (tetralin), decahydronaphthalene (decalin), 1-nitro-naphthalene, halogenated naphthalenes, naphthol derivatives, dyes, explosives mothballs manufacturing preparation of pesticides, fungicides, detergents and wetting agents, synthetic resins, celluloids, and lubricants synthetic tanning preservative emulsion breakers scintillation counters smokeless powders. 

Many synthetic applications have been reported of the photochemical reactions of halogen-substituted 1,4-naphthoquinones with 1,1-diarylethenes487 90, and with related electron-rich alkenes such as 1-aryl-l-trimethylsilyloxyethenes491 93, 2-trimethylsilyloxy-1-alkenes494, 2-methoxy-l-alkenes495 and allyltributylstannane496,497. The process is exemplified by the reaction of 2-bromo-3-methoxy-1,4-naphthoquinone derivatives (152) with 1,1-diphenylethene487 (equation 129). 

Interest continues in the photoreactions of quinones, especially anthraquinones, in which substitution occurs in one of the aromatic rings. In the 1,4-naphthoquinone series, irradiation of an aqueous solution of sodium 1,4-naphthoquinone-2-sulphonate gives a mixture of products including the 5-hydroxy-compound the effects of pH, irradiation wavelength, solvents, and radical scavengers are described. Replacement of halogen by butylamino in anthraquinone (103) is... 

It is appropriate to notice here that halogenoquinones react with pyridine bases to give quaternary salts by halogen displacement. 2,3-Dichloro-1,4-naphthoquinone gives with pyridine, by hydrolysis of the initial product. 

Another naphthoquinone antitumor agent is 2,3-bis(bromomethyl)1, naphthoquinone, 22. The presence of halogen makes for interesting mechanistic ramifications. 

A special case was the irradiation of 3-substituted 1,2-naphthoquinones with aliphatic aldehydes (Scheme Photolysis of the 3-halogenated derivatives afforded the corresponding monoesters... 

TABLE 88.15 Regioselective Acylations of Halogen-Substituted 1,4-Naphthoquinones ... 

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