1,2,4,5-Tetrabromobenzene

1,2,4,5-Tetrabrombenzol Struktur.svg 150px 1,2,4,5-Tetrabromobenzene 636-28-2 correct CAS 11974 12486 211-253-3 M25DK66LCZ 1S/C6H2Br4/c7-3-1-4(8)6(10)2-5(3)9/h1-2H QCKHVNQHBOGZER-UHFFFAOYSA-N C1=C(C(=CC(=C1Br)Br)Br)Br C6H2Br4 393.70 g/mol white solid 2.518 g/cm3 180–182 Warning 07 315 319 335 413 261 264 271 273 280 302+352 304+340 305+351+338 312 321 332+313 337+313 362 403+233 405 501 1,2,4,5-Tetrabromobenzene is an aryl bromide and a four-substituted bromobenzene with the formula C6H2Br4. It is one of three isomers of tetrabromobenzene. The compound is a white solid. 1,2,4,5-Tetrabromobenzene is an important metabolite of the flame retardant hexabromobenzene.E. Bruchajzer B. Frydrych J.A. Szymanska Int. J. Occup. Med. Environ. Health Effect of repeated administration of hexabromobenzene and 1,2,4,5-tetrabromobenzene on the levels of selected cytochromes in rat liver 17 3 347–353 2004 10.1016/S0040-4020(01)87581-5 15683155 Preparation The synthesis of 1,2,4,5-tetrabromobenzene has already been reported in 1865 from benzene and excess bromine in a sealed tube at 150 °C.A. Riche, P. Bérard Liebigs Ann. Chem. Ueber die bromhaltigen Derivate des Benzols und seiner Homologen 133 1 51–54 1865 German 10.1002/jlac.18651330106 https://zenodo.org/record/1427241 However, the clearly reduced melting point of about 160 °C indicates impurities in the final product. In his 1885 dissertation, Adolf Scheufelen published the synthesis of a purer sample using iron(III) chloride FeCl3 as a catalyst, isolated as "pretty needles" ("schönen Nadeln").A. Scheufelen Liebigs Ann. Chem. Ueber Eisenverbindungen als Bromüberträger 231 2 152–195 1885 German 10.1002/jlac.18852310204 https://zenodo.org/record/1427393 350px|center|Synthese von 1,2,4,5-Tetrabrombenzol The synthesis can also be carried out in solution in chloroform or tetrachloromethane and yields 1,2,4,5-tetrabromobenzene in 89% yield. US 2979537 Selective bromination of benzene 1961-4-11 1959-2-4 A.A. Asadorian The Dow Chemical Co. Google This reaction can also be carried out in a laboratory experiment with excess bromine and iron nails (as starting material for iron (III) bromide FeBr3).B. Cox D.G. Kubler C.A. Wilson J. Chem. Educ. Experiments with electrophilic aromatic substitution reactions 54 6 379 1977 10.1021/ed054p379 1977JChEd..54..379C The intermediate stage is 1,4-dibromobenzene, which reacts further with excess bromine to give 1,2,4,5-tetrabromobenzene. Reactions Building block for liquid crystals and fluorescent dyes Owing to its symmetrical structure and reactivity, 1,2,4,5-tetrabromobenzene is a precursor to nematic liquid crystalsH.-H. Chen et al Chem. Eur. J. Enantiotropic nematics from cross-like 1,2,4,5-tetrakis(4'-alkyl-4-ethynylbiphenyl) benzenes and their biaxiality studies 18 31 9543–9551 2012 10.1002/chem.201103453 22745006 with crossed mesogens and for columnar (discotic) liquid crystalsS. Kumar Chemistry of discotic liquid crystals: from monomers to polymers CRC Press Boca Raton, FL, U.S.A. 200 978-1-4398-1145-0 2011M.C. Artal K.J. Toyne J.W. Goodby J. Barbera D.J. Photinos J. Mater. Chem. Synthesis and mesogenic properties of novel board-like liquid crystals 11 2801–2807 2011 11 10.1039/B105351P with an extensive planar, "board-like" tetrabenzoanthracene core. 300px|right|thumb|Synthesis of discotic LC from 1,2,4,5-Tetrabromobenzene. In a one-pot reaction, 1,2,4,5-tetrabromobenzene reacts with 4-hydroxybenzaldehyde, the alkylating agent 1-bromopentane, the Wittig reagent methyltriphenylphosphonium iodide, the base potassium carbonate, the phase transfer catalyst tetrabutylammonium bromide, the Heck reagent palladium(II)acetate and the Heck co-catalyst 1,3-bis(diphenylphosphino)propane (dppp) in dimethylacetamide obtaining directly a symmetrical tetraalkoxylstilbene as E-isomer in 17% yield.K.N. Patel B.V. Kamath A.V. Bedekar Tetrahedron Lett. Synthesis of alkyloxy stilbenes by one-pot O-alkylation-Wittig and O-alkylation-Wittig-Heck reaction sequence 54 1 80–84 2013 10.1016/j.tetlet.2012.10.102 500px|center|Synthese eines symmetrischer Tetraalkoxystilbens Due to their pronounced π-conjugation such compounds could be potentially applied as optical brighteners, OLED materials or liquid crystals. N-alkyl-tetraaminobenzenes are available from 1,2,4,5-tetrabromobenzene in high yields, which can be cyclized with triethyl orthoformate and acids to benzobis(imidazolium) salts (BBI salts) and oxidized with oxygen to form 1,4-benzoquinone diimines.D.M. Khramov A.J. Boydston C.W. Bielawski Org. Lett. Highly efficient synthesis and solid-state characterization of 1,2,4,5-tetrakis(alkyl- and arylamino)benzenes and cyclization to their respective benzobis(imidazolium) salts 8 9 1831–1834 2006 10.1021/ol060349c 16623562 500px|center|Synthese von BBI-Salzen und Benzochinondiiminen BBI salts are versatile fluorescent dyes with emission wavelengths λem between 329 and 561 nm, pronounced solvatochromism and strong solvent-dependent Stokes shift, which can be used as protein tag for fluorescent labeling of proteins.A.J. Boydston J. Am. Chem. Soc. Modular fluorescent benzobis(imidazolium)saltes: Syntheses, photophysical analyses, and applications 130 10 3143–3156 2008 10.1021/ja7102247 18271588 2008JAChS.130.3143B Starting material for arynes From 1,2,4,5-tetrabromobenzene, a 1,4-monoarine can be prepared in-situ with one equivalent of n-butyllithium by bromine abstraction, which reacts immediately with furan to form 6,7-dibromo-1,4-epoxy-1,4-dihydronaphthalene (6,7-dibromonaphthalene-1,4-endoxide) in 70% yield. 500px|center|Bildung eines 1,4-Monoarins aus 1,2,4,5-Tetrabrombenzol When 2,5-dialkylfurans (e.g. 2,5- (di-n-octyl)furan) are used, the dibrominated monoendoxide is formed in 64% yield, from which dibromo-5,8-di-n-octylnaphthalene is formed with zink powder/titanium tetrachloride in 88% yield.Z. Chen P. Müller T.M. Swager Org. Lett. Syntheses of soluble, π-stacking tetracene derivatives 8 2 273–276 2006 10.1021/ol0526468 16408893 500px|center|Synthese von Dibromdioctylnaphthalin aus 1,2,4,5-Tetrabrombenzol Upon treatment with titanium tetrachloride and zinc dust, the endoxide is deoxygenated yielding 2,3-dibromnaphthalene.H. Hart C.-Y. Lai G.C. Nwokogu S. Shamouilian Tetrahedron Tetrahalobenzenes as diaryne equivalents in polycyclic arene synthesis 43 22 5203–5224 1987 10.1016/S0040-4020(01)87696-1 The endoxide reacts with 3-sulfolene in a Diels-Alder reaction upon elimination of sulfur dioxide. The resulting tricyclic adduct converts to 2,3-dibromoanthracene in good yield.C.-T. Lin T.-C. Chou Synthesis Synthesis of 2,3-dibromoanthracene 1988 8 628–630 1988 10.1055/s-1988-27659 93109532 If the dibromene oxide is allowed to react further with furan, in the presence of n-butyllithium or potassium amideF. Raymo F.H. Kohnke F. Cardullo Tetrahedron The regioselective generation of arynes from polyhalogenobenzenes. An improved synthesis of syn- and anti-1,4,5,8,9,12-hexahydro-1,4:5,8:9,12-triepoxytriphenylene 48 33 6827–6838 1992 German 10.1016/S0040-4020(01)89874-4 or via an intermediate 1,4-aryne the tricyclic 1,4-adduct 1,4:5.8-diepoxy-1,4,5,8-tetrahydroanthraceneH. Hart N. Raju M.A. Meador D.L. Ward J. Org. Chem. Synthesis of heptiptycenes with face-to-face arene rings via a 2,3:6,7-anthradiyne equivalent 48 23 4357–4360 1983 10.1021/jo00171a039 is formed in 71% yield as a syn-anti-mixture. With sodium amide in ethylene glycol dimethyl ether (DME), however, the dibromene oxide behaves as a 1,3-aryne equivalent and forms with furan a phenanthrene-like tricyclic 1,3-adduct, which can react with furan and sodium amide to a triphenylene derivative (1,3,5-tris-arene). [2+4] cycloadditions with 1,2,4,5-tetrabromobenzene sometimes proceed in very high yields, such as the reaction of a dihalogen-substituted 1,3-diphenyl-isobenzofuran to a tetrahalogenated anthracene derivative (98%), which is converted successively further with 1,3-diphenyl isobenzofuran in 65% yield to a pentacene derivative and furan to a hexacene derivative (67%).S. Eda, T. Hamura Molecules Selective Halogen-Lithium Exchange of 1,2-Dihaloarenes for Successive [2+4] Cycloadditions of Arynes and Isobenzofurans 20 19449–19462 2015 10 10.3390/molecules201019449 6331892 26512641 free 500px|center|Bildung eines Hexacen-Derivats aus 1,2,4,5-Tetrabrombenzol The crosslinking of benzimidazole-modified polymers provides materials with a high absorption capacity for carbon dioxide, which could be suitable for CO2 separation from gas mixtures.S. Altarawneh S. Behera P. Jena H.M. El-Kaderi Chem. Commun. New insights into carbon dioxide interactions with benzimidazole-linked polymers 50 3571–3574 2014 27 10.1039/C3CC45901B 24567950 450px|center|Bildung eines vernetzten Benzimidazolpolymers It is the starting material for mono- and bis-aryines.10.15227/orgsyn.075.0201 free USE OF 1,2,4,5-Tetrabromobenzene as a 1,4-Benzadiyne Equivalent: Anti- and Syn-1,4,5,8-Tetrahydroanthracene 1,4:5,8-Diepoxide Organic Syntheses 1998 75 201 K. Shahlai S. O. Acquaah H. Hart Safety 1,2,4,5-Tetrabromobenzene is a liver toxic degradation product of the flame retardant hexabromobenzene and was detected in Japan in 1987 in human mother's milk samples.T. Miyazaki T. Yamagishi M. Matsumoto Food Hygiene and Safety Science Determination and residual levels of 1,2,4,5-tetrabromobenzene and Mirex in human milk samples 28 2 125–129 1987 10.3358/shokueishi.28.125 free References Category:Bromobenzenes