Anthracene 9-bromo

Dehydrobenzene or benzyne 158 can be trapped by all manner of species. 1,2-Dehydro-o-carborane 159 has been shown to undergo many of the same reactions as its two-dimensional relative, 1,2-dehydrobenzene. Although dehydroaromatic molecules can be formed in a variety of ways, synthetic pathways to 1,2-dehydro-o-carborane are quite limited. An effective procedure reported so far78 first forms the dianion by deprotonation of o-carborane with 2 equiv. of butyllithium. Precipitated dilithium carborane is then treated with 1 equiv. of bromine at 0°C to form the soluble bromo anion 160. Thermolysis of 160 with anthracene, furan, and thiophene as substrates leads to the adducts 161-164.79 80 1,2-Dehydro-o-carborane reacts with norbomadiene to give both homo 2+4 and 2+2 addition, leading to three products 165-167, in a 7 1 ratio79. An acyclic diene, 2,3-dimethyl-... 

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>... 

As discussed in Section 15.5.2, the separation of two or more sublimable substances by fractional sublimation is theoretically possible if the substances form true solid solutions. Gillot and Goldberger(10°) have reported the development of a laboratory-scale process known as thin-hlm fractional sublimation which has been applied successfully to the separation of volatile solid mixtures such as hafnium and zirconium tetrachlorides, 1,4-dibromobenzene and l-bromo-4-chlorobenzene, and anthracene and carbazole. A stream of inert, non-volatile solids fed to the top of a vertical fractionation column falls counter-currently to the rising supersaturated vapour which is mixed with an entrainer gas. The temperature of the incoming solids is maintained well below the snow-point temperature of the vapour, and thus the solids become coated with a thin film (10. im) of sublimate which acts as a reflux for the enriching section of the column above the feed entry point. 

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... 

Complete deoxygenation of quinones to hydrocarbons is accomplished in yields of 80-85% by heating with a mixture of zinc, zinc chloride and sodium chloride at 210-280° [932]. Refluxing with stannous chloride in acetic and hydrochloric acid followed by refluxing with zinc dust and 2 N sodium hydroxide reduced 4 -bromobenzo[5. 6 1.2]anthraquinone to 4 -bromo-benzo[5. 6 1.2]anthracene in 95% yield [181], and heating with iodine, phosphorus and 47% hydriodic acid at 140° converted 2-chloroanthraquinone to 2-chloroanthracene in 75% yield [222]. Also aluminum in dilute sulfuric add can be used for reductions of the same kind [151]. 

Benzaldehyde, 4-ethoxy-3-methoxy-, 56, 44 Benzaldehyde, 4-ethoxy-3-methoxy-, ethylene acetal, 56, 44 Benzaldehyde, 4-isopropyl-, 55,10 Benz[e ] anthracene, 58, 15, 16 BENZENAMINE, 4-bromo-Ar, V-dimcthyl-3-(tnfluoromethyl)-, 55, 20 Benzene, bromo-, 55,51 Benzene, 1 bromo-4-chloro-,55, 51 Benzene, 4-bromo-l, 2-dimethyl, 55, 51 Benzene, l-bromo-4-fluoro-, 55, 51 Benzene, 1 -bromo-4-methoxy-, 55,51 Benzene, l-bromo-3-methyl-, 55, 51 Benzene, 4-(cr/-buty 1-1-ethyl, 55, 10 Benzene, chemical hazard warning, 58, 168 Benzene, chloro-,56, 86 Benzene, l-ethyl-4-isopropyl-, 55, 10... 

The following unimportant preparative methods may be mentioned the production of /3-methyl anthraquinone by the reduction of 2-bromo-3-methyl anthraquinone 7 the oxidation of /3-methyl anthracene-7-carboxylic acid 8 and the reduction of 2-methyl anthraquinonyl-i-diazonium sulfate.9... 

The (+H, 2-epoxides of naphthalene (138) and anthracene (137) can be prepared using a similar sequence from the corresponding (—)-menthoxy-acetyl derivatives of frans-2-bromo- 1-hydroxy-1,2,3,4-tetrahydronaph-thalene and anthracene, whereas the (—)-epoxides (136 and 139) are obtainable from the (+ )-menthoxyacetyl derivatives.67 The configurations of these compounds are determined by NMR analyses and correlation with alcohols of known configuration. Solid oxide 138 is unstable, whereas... 

The benzyne functions as a dienophile towards reactive diene systems. The reactivity of the 9,10-positions in anthracene is well known (Diels-Alder reaction, Section 7.6), and addition of benzyne to 9-bromoanthracene yields the interesting cage-ring alkyl halide 9-bromotriptycene (9-bromo-9,10-o-benzenoanthracene). The reaction is incomplete and some unreacted 9-bromoanthracene remains in the crude reaction products, but may be removed by virtue of its ready conversion into a maleic anhydride adduct in a further Diels-Alder-type reaction. 

Analytical Properties Resolution of several enantiomers of polycyclic aromatic hydrocarbons, for example, chrysene 5,6-epoxide, dibenz[a,h]anthracene 5,6-epoxide, 7-methyl benz[a]anthracene 5,6-epoxide resolution of barbiturates, mephenytoin, benzodiazepinones, and succinimides direct separation of some mono-ol and diol enantiomers of phenanthrene, benz[a]anthrene, and chrysene ionically bonded to silica gel, this phase provides resolution of enantiomers of c/s-dihydroidiols of unsubstituted and methyl- and bromo-substituted benz[a]anthracene derivatives having hydroxyl groups that adopt quasiequatorial-quasiaxial and quasiaxial-quasiequatorial conformation Reference 31-35... 

Analytical Properties Ionically bonded to silica, this phase provides good resolution of enantiomeric quasiequatorial frans-dehydriols of unsubstituted and methyl- and bromo-substituted benz[a]anthracene derivatives covalently bonded to silica, this phase provides good resolution of enantiomeric pairs of quasidiaxial frans-dihydrodiols of unsubstituted and methyl- and bromo-substituted benz[a]anthracene derivatives by addition of a third solvent (chloroform) to the classical binary mixture (hexane-alcohol) of the mobile phase, resolution of enantiomers of tertiary phosphine oxides is possible Reference 31-33, 36, 37... 

Unlike vicinal dibromides such as 1,2-dibromoethane [124] and //mr-10,11-dibromodibenzosuberone [125] which undergo photochemical loss of bromine followed by facile thermal cleavage of the second C—Br bond, 2-(l,2-dibromo-ethyl)naphthalene (211) and 2-bromo-9-(l,2-dibromoethyl)anthracene (212) [126] require two photons for complete debromination (Scheme 9). 

The synthesis [25, 26] began with 7-bromo-l-tetralone (7), available in multigram quantity in three steps from succinic anhydride and bromobenzene [27, 28] (Scheme 1). Treatment of 7 with an aromatic aldehyde and base produces the corresponding benzylidene (e.g., 8) which couples with 7 in boron trifluoride etherate to form a pyrylium salt. This pyrylium salt is not isolated but treated with ammonia to afford functionalized spacer 9. As seen in Scheme 1, the attachment of anthracene [29] or acridine chromophores occurs in a single step. Alternatively, stepwise attachment of the aromatic chromophores allows construction of molecular tweezers 12 and 13 carrying different chromophores. With respect to efficiency, tweezers 10 and 11 are synthesized in six steps from inexpensive starting materials with overall yields of 11% and 14%, respectively. 

Similar reaction of tris(SES) triamines (diethylenetriamine and dipropylenetriamine) with a series of bis(bromo-methyl)arenes (naphthalene, anthracene) afforded arene-containing macrocycles in high yields <2001JOC2722>. Alternatively, o-nitrobenzenesulfonyl (nosyl, Ns) <2001BML1521> or nosyl/trifluoroacetyl <20010L3499> derivatives of ethylene-propylenetriamine and dipropylenetriamine were cyclized with methyl 3,5-bis(bromomethyl)benzoate... 

A comparable study was carried out on the cleavage reactions of p-bromo-, m-iodo- and p-iodo-nitrobenzene radical anions in DMF and CH3CN. The data reproduced in Table 22 show that the relationship between activation parameters with bromo- and iodo-substitution does not exhibit the anomaly observed with the substituted anthracene radical anions. The value of... 

The success of the reaction depends largely on the use of finely ground aluminum chloride and freshly prepared cyanogen bromide. Aromatic hydrocarbons—benzene, toluene, anthracene, and acenaphthene—and phenolic ethers respond favorably. However, phenanthrene gives none of the anticipated nitrile. As might be expected, a by-product is the aryl bromide. Indeed, thiophene and furan are converted largely to the a-bromo derivatives. 

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