Monoterpenes oxygenated

One consequence of the shift from grassland to shrubland is the potential for significant increases in volatile hydrocarbons added to the atmosphere. The leaves of creosotebush, Larrea tridentata, yielded 0.1 to 0.2 percent of a complex mixture of volatile compounds. That mixture contains several hundred compounds of which 100 accounted for more than 90% of the total volatiles (23). The volatiles that were identified included four monoterpene hydrocarbons, four oxygenated monoterpenes, six sesquiterpene hydrocarbons, eight aromatics like benzyl acetate and ethyl benzoate, plus... 

Foss S, J Harder (1998) Thauera linaloolentis sp. nov. and Thauera terpenica sp. nov., isolated on oxygen-containing monoterpenes (linalool, menthol, and eucalyptol) and nitrate. System Appl Microbiol 21 365-373. 

The activity of the FePeCli6-S/tert-butyl hydroperoxide (TBHP) catalytic system was studied under mild reaction conditions for the synthesis of three a,p-unsaturated ketones 2-cyclohexen-l-one, carvone and veibenone by allylic oxidation of cyclohexene, hmonene, and a-pinene, respectively. Substrate conversions were higher than 80% and ketone yields decreased in the following order cyclohexen-1-one (47%), verbenone (22%), and carvone (12%). The large amount of oxidized sites of monoterpenes, especially limonene, may be the reason for the lower ketone yield obtained with this substrate. Additional tests snggested that molecular oxygen can act as co-oxidant and alcohol oxidation is an intermediate step in ketone formation. 

Many oxygenated monoterpenes (alcohols, carbonyl compounds, esters) serve as fragrances. Here inexpensive natural starting compounds are a-pinene (4), /1-pinene (5) and limonene (6), with production volumes of about 18000, 12 000, and 30000 t a-1, respectively. 

Attractive Compounds. With the exception of (Z)-3-dodecenyl ( )-2-butenoate 213 (Scheme 24), the female produced sex pheromone of the sweetpotato weevil Cylas formicarius [389], the structures of weevil pheromones are represented by oxygenated monoterpenes, polyketides produced from propanoate units, and branched alcohols and ketones, probably originating from a mixed acetate-propanoate biosynthesis [5]. 

Whereas some species oxidize host terpenes more randomly, producing an array of rather unspecific volatiles with little information, others use highly selective enzyme systems for the production of unique olfactory signals. However, apart from transformations of monoterpene hydrocarbons of host trees, oxygenated monoterpenes may well be biosynthesized de novo by the beetles (see below). 

Oxygenated monoterpenes which are found in almost every bark beetle species attacking coniferous trees, include czs-verbenol 246, frans-verbenol 247, and myrtenol 248, representing primary products of allylic oxidation of the host terpene a-pinene 45. Further oxidation of 247 or 248 leads to the... 

If artificial castoreum scent marks are placed on the banks of a pond, beavers, C. canadensis, are more likely to visit, destroy, and re-mark the sites as the complexity of the artificial odor composition increases (Fig. 6.14). While some single phenolics from castoreum such as 4-ethylphenol trigger marking (Miiller-Schwarze and Houlihan, 1991), the response increases as the mixture grows to 4, 6,10,13, and finally 15 compounds. A mixture of 14 phenolics and 12 neutrals (mostly oxygenated monoterpenes) released responses almost as strong as whole castoreum (Schulte etal., 1995). 

Mule deer, Odocoikus hmionus hemionus, prefer juniper (Juniperus spp.) that contains lower amounts of volatile oils (i.e. oxygenated monoterpenes). Of three species tested, alligator juniper (J. deppeana) had the lowest level of volatile oils and was preferred, while Utah juniper (j. osteosperma) and Rocky Mountain juniper (J. scopulorum) ranked higher in volatile oil content and lower in preference by deer (Schwartz etal, 1980). 

Mule deer Odocoileus Jumper Juniperus sp. Oxygenated monoterpenes... 

ENANTIOMERIC DISTRIBUTION OF ODOROUS OXYGENATED MONOTERPENES IN AROMATIC PLANTS... 

Enantiomeric Distribution of Odorous Oxygenated Monoterpenes in Aromatic Plants... 

CHIRAL- GC DETERMINATION OF ENANTIOMERIC COMPOSITION OF OXYGENATED MONOTERPENES... 

A lot of published data on the separation of enantiomers of flavors and fragrances by GC is reviewed by Chirbase/Flavor database. Table 1. summarizes the enantiomer separation of oxygenated monoterpenes on chiral stationary phases of cyclodextrin derivatives by high resolution gas chromatography. 

Table 1. Enantiomer Separation of Oxygenated Monoterpenes on Chiral Stationary Phases of Cyclodextrin Derivatives by High Resolution Gas Chromatography...

Table 1 includes many but not all, chiral stationary phases used to separate the oxygenated monoterpenes. 

Ravid U, Enantiomeric distribution of oxygenated monoterpenes in some Mentha essential oils, Perfum Flavor 23(4) 25-30, 1998. 

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