2- Bromonaphthalene: Naphthalene, 2-bromo

Chemical/Physical. An aqueous solution containing chlorine dioxide in the dark for 3.5 d oxidized naphthalene to chloronaphthalene, 1,4-dichloronaphthalene, and methyl esters of phthalic acid (Taymaz et ah, 1979). In the presence of bromide ions and a chlorinating agent (sodium hypochlorite), major products identified at various reaction times and pHs include 1-bromonaphthalene, dibromonaphthalene, and 2-bromo-l,4-naphthoquinone. Minor products identified include chloronaphthalene, dibromonaphthalene, bromochloronaphthalene, bromo-naphthol, dibromonaphthol, 2-bromonaphthoquinone, dichloronaphthalene, and chlorodibromo-naphthalene (Lin et ah, 1984). 

L-naphthylmagnesium bromide. As commercial 1-bromo-naphthalene is impure, fractionation through a 17 x 600 mm. column is needed to obtain pure 1-bromonaphthalene, b.p. 105-108° (0.1-0.2 mm.), as indicated by vapor phase chromatography. 

In the case of a still less reactive halide, or one with a tendency to undergo dehydrohalogenation, it is advantageous to add a reactive halide such as 1-bromo-naphthalene or n-butyl bromide for entrainment. Thus the reaction of 0.05 mole of eyclohexyl chloride and 0.05 mole of 1-bromonaphthalene with 0.33 g. atom of magnesium and isopropanol (0.3 mole) in 50 + 20 ml. of decalin afforded a mixture of 83% of cyclohexane and 10% of cyclohexene (removable with sulfuric acid). By this procedure cyclohexyl fluoride gives cyclohexane (33%) and benzotrifluoride gives toluene (10%). Fluorobenzene is inert. 

Alkoxynaphthalenes are converted to 1-chloro- or l-bromo-2-alkoxynaphtha-lenes in near quantitative yield using copper(II) chloride or bromide. 1-Alkoxy-naphthalene affords about 70% l-alkoxy-4-bromonaphthalene with copper(II) bromide. Similarly, anisole gives a mixture of o- and p-haloanisoles. The absence of meta isomer is believed to provide evidence for the intermediacy of a radical cation of anisole.127)... 

Riding et al. [39] interpret their results for the 2- and 3-substituted pyridines in terms of the negative group effect of the nitrogen atom in the ring the distance effect of the substituents is considerable. Extension to some bromonaphthalene, anthracene and phenanthrene compounds has been made [74]. The rate coefficients (at 520°K) obtained are 1-bromo-naphthalene, 5.28 x 10 2-bromonaphthalene, 1.19 x 10 9-bromo-anthracene, 2.15 x 10 9-bromophenanthrene, 4.28 x 10 cm mole sec". ... 

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