retene

Retene
IUPAC name	7-Isopropyl-1-methylphenanthrene
Other names	Retene
Identifiers
CAS number	483-65-8
PubChem	10222
SMILES	Cc3cccc2c1ccc (C(C)C)cc1ccc23
Properties
Molecular formula	C18H18
Molar mass	234.33552
Melting point	98.5 °C
Boiling point	390 °C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Retene, methyl isopropyl phenanthrene or 1-methyl-7-isopropyl phenanthrene, C₁₈H₁₈, is a polycyclic aromatic hydrocarbon present in the coal tar fraction, boiling above 360 °C. It occurs naturally in the tars obtained by the distillation of resinous woods. It crystallizes in large plates, which melt at 98.5 °C and boil at 390 °C. It is readily soluble in warm ether and in hot glacial acetic acid. Sodium and boiling amyl alcohol reduce it to a tetrahydroretene, whilst if it be heated with phosphorus and hydriodic acid to 260 °C, a dodecahydride is formed. Chromic acid oxidizes it to retene quinone, phthalic acid and acetic acid. It forms a picrate which melts at 123-124 °C.

Retene is derived by degradation of specific diterpenoids biologically produced by conifer trees.

The presence of traces of retene in the air is an indicator of forest fires; it is a major product of pyrolysis of conifer trees.^[1] It is also present in effluents from wood pulp and paper mills.^{[citation needed]}

Retene, together with cadalene, simonellite and ip-iHMN, is a biomarker of higher plants, which makes it useful for paleobotanic analysis of rock sediments. Ratio of retene/cadalene in sediments can reveal the ratio of the genus Pinaceae in the biosphere.^[2]

References

1. ^ Unsolved Mysteries of Human Health, Community Outreach and Education Program, Oregon State University
2. ^ Y. Hautevelle, R. Michels, F. Malartre and A. Trouiller (2005). "Vascular plant biomarkers as ancient vegetation proxies and their stratigraphic use for tracing paleoclimatic changes during Jurassic in Western Europe" (abstract). Geophysical Research Abstracts 7: 10201. http://www.cosis.net/abstracts/EGU05/10201/EGU05-J-10201.pdf. 

This article incorporates text from the Encyclopædia Britannica, Eleventh Edition, a publication now in the public domain.