Orcinol

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
ChemSpider	13839080
Jmol interactive 3D	Image
PubChem	10436
UNII	534PMB3438
SMILES CC1=CC(=CC(=C1)O)O
Properties
Chemical formula	C7H8O2
Molar mass	124.13 g/mol (anhydr.)
Appearance	Crystalline
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).
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Infobox references

Orcinol is a natural phenolic organic compound that 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.

Chemistry

It can be formed by fusing extract of aloes with potash.

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. Homo-pyrocatechin is an isomer (CH1: OH: OH= 1 3 :4), 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.

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