2-Methylanthraquinone
{{Chembox
| ImageFile = 2-MeanthraquinoneStr.svg
| ImageSize =
| ImageAlt =
| PIN = 2-Methylanthracene-9,10-dione
| OtherNames = {{Unbulleted list
| β-Methylanthraquinone
|Tectoquinone}}
|Section1={{Chembox Identifiers
| CASNo = 84-54-8
| PubChem = 6773
| ChemSpiderID = 6515
| UNII = Q9P233HWAJ
| EC_number = 201-539-6
| ChEMBL = 21745
| ChEBI = 9427
| KEGG = C10405
| Beilstein = 2050523
| Gmelin = 1607902
| 3DMet = B03899
| DTXSID = DTXSID5041439
| SMILES = Cc1ccc2c(c1)C(=O)c3ccccc3C2=O
| StdInChI=1S/C15H10O2/c1-9-6-7-12-13(8-9)15(17)11-5-3-2-4-10(11)14(12)16/h2-8H,1H3
| StdInChIKey = NJWGQARXZDRHCD-UHFFFAOYSA-N
}}
|Section2={{Chembox Properties
| C=15|H=10|O=2
| MolarMass =
| Appearance = almost colorless
| MeltingPtC = 177
| BoilingPt =
| Solubility = }}
|Section3={{Chembox Hazards
| GHSPictograms = {{GHS07}}{{GHS09}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|317|410}}
| PPhrases = {{P-phrases|261|272|273|280|302+352|321|333+313|363|391|501}}
| MainHazards =
| FlashPt =
| AutoignitionPt = }}
}}
2-Methylanthraquinone, also known as β-methylanthraquinone and tectoquinone,{{cite web |title=2-Methylanthraquinone |url=https://commonchemistry.cas.org/detail?cas_rn=84-54-8 |website=CAS Common Chemistry |access-date=5 August 2023}} is an organic compound which is a methylated derivative of anthraquinone. An off-white solid, it is an important precursor to many dyes. It is present in the wood of the teak tree, where it gives the tree resistance to insects.{{cite journal |last1=Rudman |first1=P. |last2=Da Costa |first2=E. W. B. |last3=Gay |first3=F. J. |last4=Wetherly |first4=A. H. |title=Relationship of tectoquinone to durability in Tectona grandis |journal=Nature |date=8 March 1958 |volume=181 |issue=4610 |pages=721–722 |doi=10.1038/181721b0|bibcode=1958Natur.181..721R |s2cid=4159998 }}
Synthesis and reactions
The compound is produced by a double electrophilic aromatic substitution reaction of toluene with phthalic anhydride.{{cite journal|author=L. F. Fieser|doi=10.15227/orgsyn.004.0073|title=p-Toluyl-o-Benzoic Acid|journal=Organic Syntheses|volume=4|pages=73|year=1925}}{{cite journal|author=L. F. Fieser|doi=10.15227/orgsyn.004.0043|title=β-Methylanthraquinone|journal=Organic Syntheses|volume=4|pages=43|year=1925}}
It can be chlorinated to give 1-chloro-2-methylanthraquinone. Nitration gives 1-nitro-2-methylanthraquinone, which can be reduced to 1-amino-2-methyl derivative. Oxidation of the methyl group gives anthraquinone-2-carboxylic acid.{{cite book|doi=10.1002/14356007.a02_355|chapter=Anthraquinone Dyes and Intermediates|title=Ullmann's Encyclopedia of Industrial Chemistry|year=2000|last1=Bien|first1=Hans-Samuel|last2=Stawitz|first2=Josef|last3=Wunderlich|first3=Klaus|isbn=3-527-30673-0}}