Pentamethylbenzene

Pentamethylbenzene
Names
	Preferred IUPAC name 1,2,3,4,5-Pentamethylbenzene
	Other names Pentamethylbenzene
Identifiers
CAS Number	700-12-9 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:38998;
ChemSpider	12259;
ECHA InfoCard	100.010.763
PubChem CID	12784;
UNII	H6JLD3AI98 ;
CompTox Dashboard (EPA)	DTXSID6061024 ;
	InChI InChI=1S/C11H16/c1-7-6-8(2)10(4)11(5)9(7)3/h6H,1-5H3 Key: BEZDDPMMPIDMGJ-UHFFFAOYSA-N; InChI=1/C11H16/c1-7-6-8(2)10(4)11(5)9(7)3/h6H,1-5H3 Key: BEZDDPMMPIDMGJ-UHFFFAOYAT;
	SMILES Cc1cc(C)c(C)c(C)c1C;
Properties
Chemical formula	C11H16
Molar mass	148.249 g·mol−1
Density	0.917 g/cm3
Melting point	54.4 °C (129.9 °F; 327.5 K)
Boiling point	232 °C (450 °F; 505 K)
Solubility in organic solvents	soluble
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Flammable
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Pentamethylbenzene is an organic compound with the formula C₆H(CH₃)₅. It is a colourless solid with a sweet odor. The compound is classified as an aromatic hydrocarbon. It is a relatively easily oxidized benzene derivative, with E_1/2 of 1.95 V vs NHE.^[1]

Synthesis and reactions

It is obtained as a minor product in the Friedel–Crafts methylation of xylene to durene (1,2,4,5-tetramethylbenzene).^[2] Like durene, pentamethylbenzene is rather electron-rich and undergoes electrophilic substitution readily.^[3] Indeed, it is used as a scavenger for carbocations.^[4]

Pentamethylbenzene has been observed as an intermediate in the formation of hexamethylbenzene from phenol^[5] and alkylation of durene or pentamethylbenzene has been reported as a suitable starting material for the synthesis of hexamethylbenzene.^[2]

References

^ Howell, J. O.; Goncalves, J. M.; Amatore, C.; Klasinc, L.; Wightman, R. M.; Kochi, J. K. (1984). "Electron transfer from aromatic hydrocarbons and their pi-complexes with metals. Comparison of the standard oxidation potentials and vertical ionization potentials". Journal of the American Chemical Society. 106 (14): 3968–3976. doi:10.1021/ja00326a014.
^ ^a ^b Smith, Lee Irvin (1930). "Durene". Organic Syntheses. 10: 32. doi:10.15227/orgsyn.010.0032; Collected Volumes, vol. 2, p. 248.
^ Griesbaum, Karl; Behr, Arno; Biedenkapp, Dieter; Voges, Heinz-Werner; Garbe, Dorothea; Paetz, Christian; Collin, Gerd; Mayer, Dieter; Höke, Hartmut (2002). "Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_227. ISBN 978-3527306732.
^ Okaya, Shun; Okuyama, Keiichiro; Okano, Kentaro; Tokuyama, Hidetoshi (2016). "Trichloroboron-Promoted Deprotection of Phenolic Benzyl Ether Using Pentamethylbenzene as a Non Lewis-Basic Cation Scavenger". Organic Syntheses. 93: 63–74. doi:10.15227/orgsyn.093.0063.
^ Landis, Phillip S.; Haag, Werner O. (1963). "Formation of Hexamethylbenzene from Phenol and Methanol". Journal of Organic Chemistry. 28 (2): 585. doi:10.1021/jo01037a517.

[1] Howell, J. O.; Goncalves, J. M.; Amatore, C.; Klasinc, L.; Wightman, R. M.; Kochi, J. K. (1984). "Electron transfer from aromatic hydrocarbons and their pi-complexes with metals. Comparison of the standard oxidation potentials and vertical ionization potentials". Journal of the American Chemical Society. 106 (14): 3968–3976. doi:10.1021/ja00326a014.

[OrgSynth-2] Smith, Lee Irvin (1930). "Durene". Organic Syntheses. 10: 32. doi:10.15227/orgsyn.010.0032; Collected Volumes, vol. 2, p. 248.

[Ullmanns-3] Griesbaum, Karl; Behr, Arno; Biedenkapp, Dieter; Voges, Heinz-Werner; Garbe, Dorothea; Paetz, Christian; Collin, Gerd; Mayer, Dieter; Höke, Hartmut (2002). "Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_227. ISBN 978-3527306732.

[4] Okaya, Shun; Okuyama, Keiichiro; Okano, Kentaro; Tokuyama, Hidetoshi (2016). "Trichloroboron-Promoted Deprotection of Phenolic Benzyl Ether Using Pentamethylbenzene as a Non Lewis-Basic Cation Scavenger". Organic Syntheses. 93: 63–74. doi:10.15227/orgsyn.093.0063.

[5] Landis, Phillip S.; Haag, Werner O. (1963). "Formation of Hexamethylbenzene from Phenol and Methanol". Journal of Organic Chemistry. 28 (2): 585. doi:10.1021/jo01037a517.

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