p-Menthane-3,8-diol

p-Menthane-3,8-diol
IUPAC name 2-(1-Hydroxy-1-methylethyl)-5-methylcyclohexanol
Other names para-Menthane-3,8-diol; 2-Hydroxy-α,α,4-trimethylcyclohexanemethanol
Identifiers
CAS number	42822-86-6
ChemSpider	484204 Y
EC number	255–9537
ChEBI	CHEBI:48250 Y
Jmol-3D images	Image 1
SMILES OC(C1CCC(CC1O)C)(C)C
InChI InChI=1S/C10H20O2/c1-7-4-5-8(9(11)6-7)10(2,3)12/h7-9,11-12H,4-6H2,1-3H3 Y Key: LMXFTMYMHGYJEI-UHFFFAOYSA-N Y 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
Properties
Molecular formula	C10H20O2
Molar mass	172.26 g mol−1
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

p-Menthane-3,8-diol, also known as para-menthane-3,8-diol, PMD, or Menthoglycol, is an active ingredient used in insect repellents. It smells similar to menthol and acts as a coolant^[1]. PMD is found in very small quantities in the essential oil within leaves of the Eucalyptus citriodora tree. This tree is native to Australia, but is now cultivated in many warm places around the world. This oil, when refined for use in insect repellents, is known in the United States as oil of lemon eucalyptus or under the registered tradename Citriodiol. This refined oil contains approximately 64% PMD (a mixture of the cis and trans isomers of p-menthane-3,8-diol). The refined oil has been notified under the European Biocidal Products Directive (BPD) 98/8/EC under its trade name Citriodiol (PMDRBO) and is currently proceeding through the registration process with the Health and Safety Executive in the UK. It is the only natural derived active ingredient that can now be used as an insect repellent in the United States and Europe.

Because there are R and S configurations possible at carbon atoms 1, 2, and 5, PMD has eight possible stereoisomers. Each of these, and many of the possible mixtures, have their own CID number.^[2]. However, the isomeric composition is rarely specified and is commonly assumed to be racemic.

The Center for Disease Control has recognized Oil of Lemon Eucalyptus (OLE) as the only effective naturally derived substance for deterring mosquitoes carrying West Nile Virus. PMD can be synthetically manufactured; however, one study has found that repellents containing synthetic PMD mixtures are not as effective as those containing naturally derived PMD mixtures (oil of lemon eucalyptus).^[3] This study also shows that naturally-derived PMD is as effective as DEET when used in like quantities.

References

1. ^ Cool without menthol & cooler than menthol and cooling compounds as insect repellents
2. ^ PubChem Compound Search = http://www.ncbi.nlm.nih.gov/sites/entrez?db=pccompound&cmd=Link&LinkName=pccompound_pccompound_sameconnectivity_pulldown&from_uid=556998
3. ^ 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. PMID 17067054.