Tetrabromo-o-xylene

{{Chembox

| Name = Tetrabromo-o-xylene

| ImageFile = Tetrabromo-o-xylene.svg

| ImageSize = 120px

| ImageAlt =

| PIN = 1,2-Bis(dibromomethyl)benzene

| OtherNames =

|Section1={{Chembox Identifiers

| CASNo = 13209-15-9

| ChemSpiderID = 75099

| EC_number = 236-176-2

| UNII = 3WG2H68VX4

| PubChem = 83234

| StdInChI=1S/C8H6Br4/c9-7(10)5-3-1-2-4-6(5)8(11)12/h1-4,7-8H

| StdInChIKey = LNAOKZKISWEZNY-UHFFFAOYSA-N

| SMILES = C1=CC=C(C(=C1)C(Br)Br)C(Br)Br

}}

|Section2={{Chembox Properties

| C=8|H=6|Br=4

| MolarMass =

| Appearance = off white solid

| Density =

| MeltingPtC = 115-116

| BoilingPt =

| Solubility = }}

|Section3={{Chembox Hazards

| GHSPictograms = {{GHS05}}{{GHS07}}{{GHS09}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|314|335|400}}

| PPhrases = {{P-phrases|260|261|264|271|273|280|301+330+331|303+361+353|304+340|305+351+338|310|312|321|363|391|403+233|405|501}}

| MainHazards =

| FlashPt =

| AutoignitionPt = }}

}}

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 derivative is most widely studied. It is an off-white solid. The compound is prepared by the photochemical reaction of o-xylene with elemental bromine:{{cite journal |doi=10.15227/orgsyn.034.0082|title=o-Phthalaldehyde|journal=Organic Syntheses|year=1954|first1=J. C.|last1=Bill|first2=D. S.|last2=Tarbell |volume=34|page=82}}

:{{chem2|C6H4(CH3)2 + 4 Br2 → C6H4(CHBr2)2 + 4 HBr}}

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:{{cite journal |doi=10.1021/ja01533a032|title=Condensed Cyclobutane Aromatic Compounds. VIII. The Mechanism of Formation of 1,2-Dibromobenzocyclobutene; A New Diels-Alder Synthesis|year=1959|last1=Cava|first1=M. P.|last2=Deana|first2=A. A.|last3=Muth|first3=K.|journal=Journal of the American Chemical Society|volume=81|issue=24|pages=6458–6460}}

:{{chem2|C6H4(CHBr2)2 + 2 NaI → C6H4(\dCHBr)2 + 2 NaBr + I2}}

:{{chem2|C6H4(\dCHBr)2 → C6H4(CHBr)2}}

Cycloadditions of these xylylenes provides a pathway to acenes.{{cite journal |doi=10.1055/s-1986-31603|title=An Efficient Synthetic Strategy for Naphthalene Annellation of Norbornenylogous Systems|year=1986|last1=Paddon-Row|first1=Michael N.|last2=Patney|first2=Harish K.|journal=Synthesis|volume=1986|issue=4|pages=328–330|s2cid=94212857 }}

References

Category:Organobromides