Orcinol

Orcinol is an organic compound with the formula CH₃C₆H₃(OH)₂. It occurs in many species of lichens[2] including Roccella tinctoria and Lecanora. Orcinol has been detected in the "toxic glue" of the ant species Camponotus saundersi. It is a colorless solid. It is related to resorcinol, 1,3-C₆H₄(OH)₂.

Orcinol[1]

Names
IUPAC name 5-Methylbenzene-1,3-diol
Other names 5-Methylresorcinol 3,5-Toluenediol Orcin 5-Methyl-1,3-benzenediol 3,5-Dihydroxytoluene
Identifiers
CAS Number	504-15-4^Y
3D model (JSmol)	Interactive image
ChemSpider	13839080^N
ECHA InfoCard	100.007.259
PubChem CID	10436
UNII	534PMB3438^N
CompTox Dashboard (EPA)	DTXSID2060123
SMILES CC1=CC(=CC(=C1)O)O
Properties
Chemical formula	C7H8O2
Molar mass	124.139 g·mol^−1
Appearance	Crystalline solid
Melting point	110.0 to 110.5 °C (230.0 to 230.9 °F; 383.1 to 383.6 K) (–107 °C anhydr.)
Boiling point	290 °C (554 °F; 563 K) (289.5 °C)
Solubility in water	Miscible
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is ^YN ?)
Infobox references

Synthesis and reactions

Orcinol was first prepared by dehydroacetic acid, a conversion that involved ring-opening of the pyrone to a triketone. This early experiment helped establish the rich condensation chemistry of polyketides.[3] It can be obtained by fusing extract of aloes with potash, followed by acidification.

It undergoes O-methylation with dimethylsulfate.[4]

It is used in the production of the dye orcein and as a reagent in some chemical tests for pentoses, such as Bial's Test. It may be synthesized from toluene; more interesting is its production when acetone dicarboxylic ester is condensed with the aid of sodium. It crystallizes in colorless prisms with one molecule of water, which redden on exposure to air. Ferric chloride gives a bluish-violet coloration with the aqueous solution. Unlike resorcinol it does not give a fluorescein with phthalic anhydride. Oxidation of the ammoniacal solution gives orcein, C₂₈H₂₄N₂O₇, the chief constituent of the natural dye archil. 4-Methylcatechol is an isomer, found as its methyl ether (creosol) in beech-wood tar.

Orcinol

See also

• Orcinol 2-monooxygenase
• Orsellinate decarboxylase

References

1. Merck Index, 11th Edition, 6819.
2. Robiquet: „Essai analytique des lichens de l’orseille“, Annales de chimie et de physique, 1829, 42, p. 236–257.
3. Staunton, James; Weissman, Kira J. (2001). "Polyketide Biosynthesis: A Millennium Review". Natural Product Reports. 18: 380–416. doi:10.1039/a909079g.CS1 maint: uses authors parameter (link)
4. R. N. Mirrington, G. I. Feutrill (1973). "Orcinol Monomethyl Ether". Org. Synth. 53: 90. doi:10.15227/orgsyn.053.0090.CS1 maint: uses authors parameter (link)

•  This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Orcin". Encyclopædia Britannica. 20 (11th ed.). Cambridge University Press. p. 173.