Eucalyptus Eudesmol

Eudesmene is a sesquiterpene obtained by the dehydration of eudesmol, the sesquiterpene alcohol found by Baker and Smith in several species of eucalyptus oil. It has the following characters —... 

There are a number of allelochemicals among the mono-, sesqui-, and diterpenoids. In particular, plants in arid and semiarid regions produce diverse volatile terpenoids with allelopathic activity.5 Among the volatile monoterpenes, 1,8-cineole (4) and camphor (5) exhibit strong growth inhibitory effects on plants and are considered to be involved in plant competition. 1,4-Cineole (6), a minor isomer of 1,8-cineole, is a potent inhibitor of asparagine synthetase.6 -Menthane-3,8-diols (fir 7 and frw .r8), -menth-2-en-l-ols (cis 9 and trans 10), thymol (11), carvacrol (12), 1,8-cineole, cr-pinene (13), and /3-pinene (14) were isolated as allelopathic monoterpenes from Eucalyptus species.7 Eucalyptus trees also produce allelopathic sesquiterpenes including spathulenol (15), and a-, (3-, and 7-eudesmols (16-18).7... 

The structure of eudalene, C14H16, a degradation product of eudesmol (a terpene found in eucalyptus oil), was first established by the following synthesis ... 

Oil of Eucalyptus. Dinkum oil. Volatile oil from fresh leaves otEucalyptus globulus Labi]] and of some other species of Eucalyptus, Myrtaceae. A dwarf species, called Mallee in Australia, is richest in oil of Eucalyptus. Constit 70-80% cineole (eucalyptol) a-pinene phellandrene terpin-eo] citronella gerany] acetate eudesmol eudesmyl acetate piperitone volatile aldehydes (principally isovaleric) E. Guenther, The Essential Oils vol. 4 (van Nostrand, New York, 1950) pp 437-525. 

Well-known eudesmane derivatives in flavors and fragrances include a- and p-selinene from the oils of Cannabis saliva var. indica (Moraceae), celery (Apium graeveolens, Umbelliferae) and hops (Humulus lupulus, Moraceae), (+)-a- and (+)-P-eudesmol from some oils of eucalyptus (Eucalyplus macarlhuri), (-)-epi-y-eudesmol with its woody odor from the north African oil of geranium (Pelargonium odoralissimum and allied species), and the almost odorless diastereomeric (+)-y-eudesmol from various ethereal oils (+)-p-Costus acid and (+)-p-costol belong to the constituents of the essential oil obtained from the roots of Saussurea... 

A volatile oil from the fresh leaves of Eucalyptus globulus labill and other species of Eucalyptus and Myrtaceae. Constitutes 70-80% cineole (aucalytol), pinene, phellandrene, terpineol, citronelal, geranyl acetate, eudesmol, eudesmyl acetate, piperitone, and volatile aldehydes. The oil is a colorless to pale yellow, mobile liquid that has a strong and very fresh, rosy citronella like odor and a sweet, balsamic floral dryout note... 

The main functional component of eucalyptus oil is eudesmol. The stmcmre of eudesmol is as follows ... 

The physical properties of eucalyptus oil are as follows density, 0.913-0.918 refractive index, 1.4589 eudesmol content, 40-50 % iodine value, 67 and surface tension, 24 x 10 J/m. ... 

Among the oxygenated sesquiterpenes (Fig. 96.12), the oxidation product from p-caryophyllene, caryophyllene oxide, is widespread in plants. Also spathulenol is a widespread sesquiterpene alcohol. For example, it occurs in German chamomile and together with y-eudesmol as major oil component in Eucalyptus oleosa [36]. Daucol and carotol are aroma components found in the fruit oils from carrots (Daucus carotd) [27]. 

Eudesmol is a sesquiterpene found in eucalyptus. Propose a mechanism for its biosynthesis. 

Eudesmol, which has been also named eucalyptus camphor, was first isolated from the oil of Eucalyptus piperita by H. G. Smith, who found it to be a crystalline body melting at 79 to 80, and having the formula Cxo xsO, and being, in all probability, an oxide. Semmler and Mayer, however, consider it to be a bii clic sesquiterpene alcohol, and this has since been confirmed by Semmler and Tobias, who give the following as its characters —... 

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