Anthracene 9,10-dibromo

Coke (coal tar), high temperature pitch Coke (coal tar), mixed coal-high temperature pitch Coke (coal tar), low temperature, high temperature pitch Diaminotoluene o-Dianisidine Salts of o-dianisidine o-Dianisidine-based azodyes Diarsenic trioxide Diazomethane Dibenz(a,/i)anthracene 1,2-Dibromo-3-chloropropane... 

UN 2810, see Benzyl alcohol, Bromodichloromethane, Dibromochloromethane, Glycidol, p-Propiolactone UN 2811, see 4-Aminobiphenyl,Benzo[a]anthracene, Benzo[a]pyrene, Benzo[e]pyrene, p-Dimethylaminoazobenzene, Indole UN 2821, see Phenol UN 2831, see 1,1,1-Trichloroethane UN 2842, see Nitroethane UN 2872, see l,2-Dibromo-3-chloropropane UN 2874, see Furfuryl alcohol UN 2976, see CiS-Chlordane, frans-Chlordane UN 2995, see Chlordane UN 2996, see Chlordane UN 3077, see Acenaphthene, Acenaphthylene,... 

Anthracene undergoes 1,4-addition and phenanthrene undergoes 1,2-addition, and in each case the 9,10-dibromo derivative is formed. Each product has two fully aromatic benzene rings—this could not be said of any other dibromo product. 

Anthracene was oxidized to anthraquinone. dibrominated, and the dibromo derivative subjected to a caustic fusion. Alizarin was obtained in an impure form and in low yield. This represented the first synthesis of a natural dye. 

The crystal structures of a series of anthracene derivatives (9-nitro- and 9,10-dinitro-anthracene, 9,10-dichloro- and 9,10-dibromo-anthracene, and 9-anthraldehyde) have been investigated by Trotter (1958a, 1959a, b). In 9-anthraldehyde (65) significant out-of-plane... 

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). 

Ozonolysis of 9,10-dibromo- (17a) and 9,10-dichloroanthracene (17b) was reported to occur partly by attack at the non-halogenated double bonds to yield the di- (18) and tetracarboxylic acids, 19, as well as by attack at the 9,10-positions to yield the dehalogenated product anthra-quinone, 22 (8). This dual attack might at first seem to be in contrast to what was said above about the relative rates of ozone attack at halo-genated and non-halogenated double bonds. However, this is not the case if one considers that (in analogy to the ozonolysis of the unsubstituted anthracene) the reaction at the 9,10-positions has to be formulated as an atom- rather than a bond attack. In accordance with such a rationalization, the authors (8) formulated the intermediates 20 and 21 as precursors for anthraquinone. 

Anthracene peroxide reacts with concentrated hydrochloric acid to give 9-oxo-10-chloroanthracene, while the reaction with hydrobromic acid gives either 9-oxo-10-bromoanthracene or 9,10-dibromo-9,10-dihydroanthracene, depending on the reaction conditions.227... 

Most of these excitation yields have been determined by energy-transfer chemiluminescence using 9,10-diphenylanthracene (JJPA) and 9,10-dibromo-anthracene DBA) as fluorescers. 

In the cyclopropanaphthalene and cyclopropanthracene series, the dichloro analogs are more easily obtained. Thus, l,l-dichloro-l/f-cyclopropa[6]naphthalene (8) and l,l-dichloro-2,7-diphenyl-l//-cyclopropa[A]naphthalene (10, X = Cl) were prepared in 66% and 88% yield, respectively. The dibromo analog 10 (X = Br) was also detected in solution but could not be isolated. Similarly, l,l-dichloro-l/f-cycloprop[f)]anthracene (12) was obtained in 70% yield but could not be purified. ... 

Bromine adducts in which not all the C=C bonds are saturated are more easily prepared from polycyclic aromatic hydrocarbons. Thus 1,2,3,4-tetra-bromo-l,2,3,4-tetrahydronaphthalene is obtained by brominating pure naphthalene in anhydrous CC14 at 0° with irradiation (30% yield)134 or in CC14 at room temperature with irradiation and addition of peroxide (ascaridole) (12% yield).135 Anthracene adds bromine in CS2 at 0°, giving 9,10-dibromo-9,10-dihydroanthracene,136,137 and phenanthrene in ether138 or carbon disulfide139 gives 9,10-dibromo-9,10-dihydrophenanthrene when warmed, these two products pass into 9-monobromo derivatives by loss of HBr. 

It should be noted that NBS can cause nuclear bromination when that reaction occurs readily. In the absence of a catalyst it can brominate the nucleus of condensed aromatic compounds such as naphthalene, anthracene, and phenanthrene,399 veratrole, the dimethyl ethers of resorcinol and hydro-quinone,389 and pyrogallol trimethyl ether.390 Pyrocatechol and 2 moles of NBS afford 4,5-dibromopyrocatechol resorcinol and 3 moles of NBS afford 2,4,6-tribromoresorcinol 391,392 and anthranilic or o- or/ -hydroxybenzoic acid with 2 moles of NBS afford the 4,5- or 3,5-dibromo derivatives.391-393 However, nuclear bromination of benzene and toluene is effected by NBS only if equimolar amounts of A1C13, ZnCl2, FeCl3, or H2S04 are added. 

The iV-phenylmaleimide derivative (518), prepared in two steps from a-pyrone and nitrosobenzene, is a dienophile and yields the cycloaddition product (519) on reaction with cyclohexa-l,3-diene." ° The sealed-tube reaction of anthracene with excess l,2-dibromo-3,3-difluorocyclopropene at 120°C gave the crystalline adduct (520), presumably by way of intermediate (521) the mechanism is not known. A synthesis of the tricyclo[5,2,2,0 ]undecane skeleton related to isoeremolactone has been reported. The Diels-Alder adduct (522) was a key intermediate in this synthesis, being converted in two standard steps into an epimeric mixture of compounds... 

Dibromo anthracene C (367) 0.6 part C, CHCI3 solution 2- -SOjH... 

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