2- Bromo naphthalene

Naphthoic acid has been prepared principally by the hydrolj sis of d-naphthonitriled the overall yields from (3-naph-thylamine, from sodinm-/3-naphthalene sulfonate, and from calcium d-naphthalene sulfonate being given as (approximately) 20 per cent, 21 per cent, and 50 per cent, respectively. The acid has been prepared also by the carbonation of the Grignard reagent from the less accessible /3-bromo derivative and. more recendy, from the readily available methyl ketone. ... 

The reactivities of 4- and 2-halo-l-nitronaphthalenes can usefully be compared with the behavior of azine analogs to aid in delineating any specific effects of the naphthalene 7r-electron system on nucleophilic substitution. With hydroxide ion (75°) as nucleophile (Table XII, lines 1 and 8), the 4-chloro compound reacts four times as fast as the 2-isomer, which has the higher and, with ethoxide ion (65°) (Table XII, lines 2 and 11), it reacts about 10 times as fast. With piperidine (Table XII, lines 5 and 17) the reactivity relation at 80° is reversed, the 2-bromo derivative reacts about 10 times as rapidly as the 4-isomer, presumably due to hydrogen bonding or to electrostatic attraction in the transition state, as postulated for benzene derivatives. 4-Chloro-l-nitronaphthalene reacts 6 times as fast with methanolic methoxide (60°) as does 4-chloroquinoline due to a considerably higher entropy of activation and in spite of a higher Ea (by 2 kcal). ... 

Bromo-6-m ethoxy naphthalene Ethyl bromoisobutyrate Magnesium Hydrogen... 

Benzene- 1,2-diacetonitriles e.g. 19, in the presence of hydrogen bromide in acetic acid, or in diethyl ether, cyclize to 4-bromo-l //-3-benzazepin-2-amines, e.g. 20a.41,42 l//-Naphtho[2,3-t/]azepines, e.g. 22a, are prepared in a similar manner from naphthalene-2,3-diacetonitriles, e.g. 21.41 Replacement of hydrogen bromide by hydrogen iodide yields the corresponding 4-iodo derivatives, e.g. 20b and 22b. 

The isomeric naphthalene-1,2-diacetonitrile (23) behaves differently in that with hydrogen bromide in acetic acid a mixture of 4-bromo-l //-naphtho[2,l-r/]azepin-2-amine (24) and 4-bromo-l//-naphtho[l, 2-r/]azepin-2-amine (25) is formed, from which only one isomer (32% mp 232-238 °C dec.), of undetermined structure, was isolated and purified.41... 

Gore et al.426 have used chloroform as a solvent for acetylation catalysed by aluminium chloride and at 45-55 °C find that a 2-methoxy substituent in naphthalene increases the reactivity of the 1 position 1.72 times, of the 6 position 3.8 times, and of the 8 position, 0.9 times the former and latter of these results indicate a considerable steric effect. Likewise, a 2-bromo substituent caused the reactivity of the 6 and 8 positions to be 0.63 and 0.58 times that of the corresponding positions in the unsubstituted compound. At 20-25 °C the relative reactivities of some polycyclics were as follows427 1-naphthyl, 1.0 3-phenanthryl 0.64 9-phenanthryl, 0.02 1-phenanthryl, 0.29 2-naphthyl, 0.28 2-phenanthryl, 0.12 4-phenanthryl, 0.0085. Some of these results seem to be due to steric hindrance, and the large difference in reactivity of naphthalene and biphenyl seems erroneous. 

Betzemeier et al. (1998) have used f-BuOOH, in the presence of a Pd(II) catalyst bearing perfluorinated ligands using a biphasic system of benzene and bromo perfluoro octane to convert a variety of olefins, such as styrene, p-substituted styrenes, vinyl naphthalene, 1-decene etc. to the corresponding ketone via a Wacker type process. Xia and Fell (1997) have used the Li salt of triphenylphosphine monosulphonic acid, which can be solubilized with methanol. A hydroformylation reaction is conducted and catalyst recovery is facilitated by removal of methanol when filtration or extraction with water can be practised. The aqueous solution can be evaporated and the solid salt can be dissolved in methanol and recycled. 

The reaction of potassium 3-amino-4-oxo-3,4-dihydroquinazoline-2-thiolate 62 with a-bromophenylacetic acid 63 resulted in the formation of (3-amino-4-oxo-3,4-dihydroquinazolin-2-ylsulfanyl)-phenyl-acetic acid methyl ester 64 which on alkali treatment and subsequent acidification resulted in the synthesis of 2-phenyl- 1-thia-4,4a,9-triaza-anthracene-3,10-dione 65 <1999JCR(S)86>. Similarly, the reaction of potassium 3-amino-5,6-dimethyl-4-oxo-3,4,4a,7a-tetrahydrothieno[2,3- pyrimidine-2-thiolate 66 with a-bromo-ester 67 resulted in the formation of 2-(3-amino-5,6-dimethyl-4-oxo-3,4,4a,7a-tetrahydrothieno[2,3- / pyrimidin-2-ylsulfanyl)-propionic acid ethyl ester 68. Subsequent treatment with alkali followed by acidification resulted in the formation of 2,3,7-trimethyl-3a,9a-dihydro-l,8-dithia-4a,5,9-triazacyclopenta[ ]naphthalene-4,6-dione 69 <2000JHC1161>... 

Now the interesting question arose of whether the intermediate analogous to 215 but devoid of the methyl groups, that is, 3d2-l H-naphthalene (221), would also be interceptable, because 221 should show a high thermodynamic acidity owing to its conversion into the 2-naphthyl anion (224) on deprotonation and because of the use of the strong base KOtBu for the liberation of 221 from 3-bromo-l, 2-dihydro-naphthalene (220) (Scheme 6.52). In the event, the major product was indeed naphthalene. However, there were further products, namely the enol ether 223 and small quantities of 2,2 -binaphthyl (228) as well as 1,2-dihydronaphthalene (226). The overall yield amounted to 92% [137]. 

Scheme 6.52 Generation of 3<52-l H-naphthalene (221) by /j-elimination from 3-bromo-l, 2-dihydronaphthalene (220) and reaction sequences started by attacks of KOtBu at 221.

Lund and coworkers [131] pioneered the use of aromatic anion radicals as mediators in a study of the catalytic reduction of bromobenzene by the electrogenerated anion radical of chrysene. Other early investigations involved the catalytic reduction of 1-bromo- and 1-chlorobutane by the anion radicals of trans-stilhene and anthracene [132], of 1-chlorohexane and 6-chloro-l-hexene by the naphthalene anion radical [133], and of 1-chlorooctane by the phenanthrene anion radical [134]. Simonet and coworkers [135] pointed out that a catalytically formed alkyl radical can react with an aromatic anion radical to form an alkylated aromatic hydrocarbon. Additional, comparatively recent work has centered on electron transfer between aromatic anion radicals and l,2-dichloro-l,2-diphenylethane [136], on reductive coupling of tert-butyl bromide with azobenzene, quinoxaline, and anthracene [137], and on the reactions of aromatic anion radicals with substituted benzyl chlorides [138], with... 

Covalent protein adducts of quinones are formed through Mchael-type addihon reachon with protein sulfhydryl groups or glutathione. Metabolic activahon of several toxins (e.g., naphthalene, pentachlorophenol, and benzene) into quinones has been shown to result in protein quinone adducts (Lin et al, 1997 Rappaport et al, 1996 Zheng et al., 1997). Conversion of substituted hydroquinones such as p-aminophenol-hydroquinone and 2-bromo-hydroquinone to their respective glutathione S-conjugates must occur to allow bioactivation into nephrotoxic metabolites (Dekant, 1993). Western blot analysis of proteins from the kidneys of rats treated with 2-bromo-hydroquinone has revealed three distinct protein adducts conjugated to quinone-thioethers (Kleiner et al, 1998). 

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). 

Bromochloroaniline, see o-Bromoaniline Bromochloromethane, see Dibromochloromethane Bromochloronaphthalene, see Naphthalene l-Bromo-3-chloropropan-2-one, see l,2-Dibromo-3-chloropropane... 

In order to allow for a closer approach of the boron centers, the introduction of flat cyclic boryl moieties with reduced steric hindrance has also been pursued. Thus, the reaction of 26 with 9-chloro-9-borafluorene and 5-bromo-10,l 1-di-hydrodibenzo[b,f]borepin resulted in the formation of diboranes 31 and 32 which bear two different boryl moieties at the pen-positions of naphthalene (Scheme 13). " These diboranes have been characterized by multinuclear NMR spectroscopy and X-ray single-crystal analysis. In 31, the boron center of the borafluorenyl moiety is 7i-coordinated by the zp o-carbon of a mesityl group with which it forms a contact of 2.730(3) A (Fig. 8). As a result of this interaction, the boron center involved in this contact is slightly pyramidalized (Xangie = 355.7°). In the case of 32 (Fig. 9), the distance between the boron center of the boracylic moiety and the zpio-carbon of... 

Cleavage of the sulfonyl esters to the parent alcohols is accomplished in yields of 60-100% by treatment of the p-toluenesulfonates with 2-6 equivalents of sodium naphthalene in tetrahydrofuran at room temperature (yields 60-100%). Sodium naphthalene is prepared by stirring sodium with an equivalent amount or a slight excess of naphthalene in tetrahydrofuran for 1 hour at room temperature under an inert gas [701]. Benzenesulfonates and bromo-benzenesulfonates are also cleaved to the parent alcohols while alkyl methanesulfonates are reduced also to hydrocarbons [701]. 

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