Orcinol is an organic compound with the formula CH₃C₆H₃(OH)₂. It occurs in many species of

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

s including ''

Roccella tinctoria ''Roccella tinctoria'' is a lichenised species of fungus in the genus '' Roccella'', homotypic synonym of ''Lecanora tinctoria'' (DC.) Czerwiak., 1849. It was first described by Augustin Pyramus de Candolle in 1805. It has the following varieti ...

'' and ''

Lecanora ''Lecanora'' is a genus of lichen commonly called rim lichens.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, Lichens in the genus '' Squamarina'' are also called rim lichens. Members of the genus have roughly c ...

''. Orcinol has been detected in the "toxic glue" of the ant species ''

Camponotus saundersi ''Colobopsis saundersi'' (synonym ''Camponotus saundersi''), also called the Malaysian exploding ant or suicide ant, is a species of ant found in Malaysia and Brunei, belonging to the genus ''Colobopsis''. A worker can explode suicidally and aggr ...

''. It is a colorless solid. It is related to

resorcinol Resorcinol (or resorcin) is a phenolic compound. It is an organic compound with the formula C6H4(OH)2. It is one of three isomeric benzenediols, the 1,3-isomer (or ''meta- (chemistry), meta''-isomer). Resorcinol crystallizes from benzene as co ...

, 1,3-C₆H₄(OH)₂.

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

polyketide In organic chemistry, polyketides are a class of natural products derived from a Precursor (chemistry), precursor molecule consisting of a Polymer backbone, chain of alternating ketone (, or Carbonyl reduction, its reduced forms) and Methylene gro ...

s. It can be obtained by fusing extract of

aloe ''Aloe'' (; also written ''Aloë'') is a genus containing over 650 species of flowering plant, flowering succulent plant, succulent plants.WFO (2022): Aloe L. Published on the Internet;http://www.worldfloraonline.org/taxon/wfo-4000001341. Acc ...

s with

potash Potash ( ) includes various mined and manufactured salts that contain potassium in water- soluble form.

, followed by acidification. It undergoes ''O''-

methylation Methylation, in the chemistry, chemical sciences, is the addition of a methyl group on a substrate (chemistry), substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replac ...

with dimethylsulfate. It is used in the production of the dye orcein and as a

reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

in some chemical tests for

pentose In chemistry, a pentose is a monosaccharide (simple sugar) with five carbon atoms. The chemical formula of many pentoses is , and their molecular weight is 150.13 g/mol.Bial's Test Bial's test is a chemical test for the presence of pentoses originally developed for the diagnosis of pentosuria. It is named after Manfred Bial, a German physician. The components include orcinol, hydrochloric acid, and ferric chloride. A pentos ...

. It may be synthesized from

toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon with the chemical formula , often abbreviated as , where Ph stands for the phenyl group. It is a colorless, water Water is an inorganic compound with the c ...

; more interesting is its production when acetone dicarboxylic ester is condensed with the aid of

sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

. It crystallizes in colorless prisms with one molecule of water, which redden on exposure to air.

Ferric chloride Iron(III) chloride describes the inorganic compounds with the formula (H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated f ...

gives a bluish-violet coloration with the aqueous solution. Unlike

it does not give a

fluorescein Fluorescein is an organic compound and dye based on the xanthene tricyclic structural motif, formally belonging to Triarylmethane dye, triarylmethine dyes family. It is available as a dark orange/red powder slightly soluble in water and alcohol. ...

with

phthalic anhydride Phthalic anhydride is the organic compound with the formula C6H4(CO)2O. It is the anhydride of phthalic acid. Phthalic anhydride is a principal commercial form of phthalic acid. It was the first anhydride of a dicarboxylic acid to be used commer ...

. Oxidation of the ammoniacal solution gives orcein, C₂₈H₂₄N₂O₇, the chief constituent of the

natural dye Natural dyes are dyes or colorants derived from plants, invertebrates, or minerals. The majority of natural dyes are vegetable dyes from plant sources—roots, berry, berries, Bark (botany), bark, leaf, leaves, and wood—and other biological sourc ...

archil. 4-Methylcatechol is an

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element (chemistry), element – but distinct arrangements of atoms in space. ''Isomerism'' refers to the exi ...

, found as its methyl ether (

creosol Creosol is a chemical compound with the molecular formula C8H10O2. It is one of the components of creosote. Compared with phenol, creosol is a less toxic disinfectant. Sources Sources of creosol include: * Coal tar creosote * Wood creosote * ...

) in

beech Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

-wood tar. : Orcin Merck 820933

Production from shale oil

Orcinol is also found in

shale oil Shale oil is an unconventional oil produced from oil shale rock fragments by pyrolysis, hydrogenation, or thermal dissolution. These processes convert the organic matter within the rock (kerogen) into synthetic oil and gas. The resulting oil c ...

produced from Kukersite oil shale. It is the main water-soluble phenol in the oil, and has been extracted and refined industrially by Viru Keemia Grupp.

References

{{Reflist Alkylresorcinols Lichen products

Synthesis and reactions

Production from shale oil

See also

References