Tetrabromo-o-xylene
α,α,α',α'-Tetrabromo-o-xylene is an organobromine compound with the formula C6H4(CHBr2)2. Three isomers of α,α,α',α'-Tetrabromoxylene exist, but the ortho derivatiive is most widely studied. It is an off-white solid. The compound is prepared by the photochemical reaction of o-xylene with elemental bromine:[1]
- C6H4(CH3)2 + 4 Br2 → C6H4(CHBr2)2 + 4 HBr
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| Names | |
|---|---|
| IUPAC name
1,2-bis(dibromomethyl)benzene | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.032.873  |
| EC Number |
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PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C8H6Br4 | |
| Molar mass | 421.752 g·mol−1 |
| Appearance | off white solid |
| Melting point | 115–116 °C (239–241 °F; 388–389 K) |
| Hazards | |
| GHS pictograms |    |
| GHS Signal word | Danger |
| H314, H318, H335, H400 | |
| P260, P261, P264, P271, P273, P280, P301+330+331, P303+361+353, P304+340, P305+351+338, P310, P312, P321, P363, P391, P403+233, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Reaction of α,α,α',α'-tetrabromo-o-xylene with sodium iodide affords α,α'-dibromo-o-xylylene, which can be trapped with dienophiles to give naphthylene. In the absence of trapping agents, the xylylene relaxes to α,α'-dibromobenzocyclobutane:[2]
- C6H4(CHBr2)2 + 2 NaI → C6H4(=CHBr)2 + 2 NaBr + I2
- C6H4(=CHBr)2 → C6H4(CHBr)2
Cycloadditions of these xylylenes provides a pathway to acenes.[3]
References
- Bill, J. C.; Tarbell, D. S. (1954). "o-Phthalaldehyde". Organic Syntheses. 34: 82. doi:10.15227/orgsyn.034.0082.
- Cava, M. P.; Deana, A. A.; Muth, K. (1959). "Condensed Cyclobutane Aromatic Compounds. VIII. The Mechanism of Formation of 1,2-Dibromobenzocyclobutene; A New Diels-Alder Synthesis". Journal of the American Chemical Society. 81 (24): 6458–6460. doi:10.1021/ja01533a032.
- Paddon-Row, Michael N.; Patney, Harish K. (1986). "An Efficient Synthetic Strategy for Naphthalene Annellation of Norbornenylogous Systems". Synthesis. 1986 (4): 328–330. doi:10.1055/s-1986-31603.
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