p-Menthane-3,8-diol,also known aspara-menthane-3,8-diol,PMD,ormenthoglycol,is anorganic compoundclassified as adioland aterpenoid.It is colorless. Its name reflects the hydrocarbon backbone, which is that ofp-menthane.A total of eightstereoisomersare possible, based on the three stereocenters of the ring. Depending on the source, one or more may predominate.

p-Menthane-3,8-diol
Names
Preferred IUPAC name
2-(2-Hydroxypropan-2-yl)-5-methylcyclohexan-1-ol
Other names
2-(1-Hydroxy-1-methylethyl)-5-methylcyclohexanol
para-Menthane-3,8-diol
2-Hydroxy-α,α,4-trimethylcyclohexanemethanol
Identifiers
3D model (JSmol)
2552262
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.050.849Edit this at Wikidata
EC Number
  • 255–9537
KEGG
UNII
  • InChI=1S/C10H20O2/c1-7-4-5-8(9(11)6-7)10(2,3)12/h7-9,11-12H,4-6H2,1-3H3checkY
    Key: LMXFTMYMHGYJEI-UHFFFAOYSA-NcheckY
  • InChI=1/C10H20O2/c1-7-4-5-8(9(11)6-7)10(2,3)12/h7-9,11-12H,4-6H2,1-3H3
    Key: LMXFTMYMHGYJEI-UHFFFAOYAL
  • OC(C1CCC(CC1O)C)(C)C
Properties
C10H20O2
Molar mass 172.268g·mol−1
Density 1.009 g/cm3
Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa).

PMD is the active ingredient in someinsect repellents.Its odor and chemical structure are similar tomenthol,and it has a cooling feel.[1]It is found in small quantities in theessential oilfrom the leaves ofCorymbia citriodora,formerly known asEucalyptus citriodora.This tree is native toAustralia,but is now cultivated in many warm places around the world.C. citriodoraoil, when refined to increase its PMD content for use in insect repellents, is known in the United States asoil of lemon eucalyptus(OLE).[2]C. citriodoraoil contains only 1–2% PMD, while refined OLE contains approximately up to 70% PMD.[3]Some commercial PMD products are not made fromC. citriodoraoil, but rather from syntheticcitronellal.

Effectiveness

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A 2006 study showed that PMD used as a repellent is as effective asDEETwhen used in like quantities.[4]

Contraindications

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PMD should not be used on children under 3 years of age.[5]

Interactions

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Few if any studies have evaluated possible interactions when using PMD with sunscreens.[6]

Chemistry

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There are eight possiblestereoisomers.[7]The exact composition is rarely specified and is commonly assumed to be a complex mixture. PMD can be synthesized by aPrins reactionofcitronellal.[3]

Refined OLE contains approximately up to 70% PMD, a mixture of thecisandtransisomersofp-menthane-3,8-diol.

History

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Its repellent effect was discovered in the 1960s by the industry.[vague]

OLE has been notified under the EuropeanBiocidal Products Directive(BPD) 98/8/EC (now BPR Regulation (EU) No. 528/212) under its generic name "PMD rich botanic oil" and is currently proceeding through the registration process with theHealth and Safety Executivein the UK. It is also registered with Canada'sPest Management Regulatory Agencyunder the generic name "PMD and related oil of lemon eucalyptus compounds".

See also

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References

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  1. ^John C. Leffingwell."Cool without menthol & cooler than menthol and cooling compounds as insect repellents".Leffingwell & Associates.
  2. ^"Home".citrepel.co.uk.
  3. ^abDrapeau, Jeremy (2011)."Green synthesis ofpara-Menthane-3,8-diol fromEucaplytus citriodora:Application for repellent products ".Comptes Rendus Chimie.14(7–8): 629–635.doi:10.1016/j.crci.2011.02.008.
  4. ^Carroll, Scott P.; Loye, Jenella (2006)."PMD, a Registered Botanical Mosquito Repellent with Deet-Like Efficacy".Journal of the American Mosquito Control Association.22(3): 507–13.doi:10.2987/8756-971X(2006)22[507:PARBMR]2.0.CO;2.PMID17067054.S2CID225645.
  5. ^"Prevent Mosquito Bites".Centers for Disease Control and Prevention.Retrieved24 September2023.
  6. ^"Insect Repellents".National Pesticide Information Center. February 2018.Archivedfrom the original on 13 September 2023.Retrieved26 September2023.Few or no studies address using IR3535 or oil of lemon eucalyptus with sunscreens.
  7. ^PubChem Compound Search