Terpenoid alcohols

The substituents may be simple, for example methyl groups, or contain functionality, such as alcohols,terpenoid substituents,esters,hydroxyamides or oxazo-lidines. In these last cases, the substituents can be expected to be involved in the supramolecular architecture of the conductor, due to the polar nature of the functions involved and hence their potential interactions (tt-tt type or hydrogen bonds). The first enantiopure organosulfur donor, reported by Dunitz, was (,S,5,5,5)-TMET (S, S, S, S)-... 

Even if all the insoluble impmities are removed from coconut oil, the oil still has up to about 0.5% of imsaponifiable matter, which includes polyphenols, alcohols, terpenoids, and several other organic substances (Kirschner Harris, 1961). Quality parameters of coconut oil are mainly and traditionally defined for the lipid fraction. However, many studies conducted in recent times show that imsaponifiable components are also important to evaluate the quality of oil. 

Absolute. This is concentrated extract obtained by treatment of a concrete or other hydrocarbon-type extract of a plant or plant part with ethanol. It is usually Hquid and should be totally soluble in alcohol. By this method, waxes, hydrocarbons (including terpenoid), as well as most of the odorless material of the concrete are removed from the extract. 

The conversion of isopentenyl diphosphate (IPP) to terpenoids begins with its isomerization to dimethylallyl diphosphate, abbreviated DMAPP and formerly called dimethylallyl pyrophosphate. These two C5 building blocks then combine to give the C10 unit geranyl diphosphate (GPP). The corresponding alcohol, geraniol, is itself a fragrant terpenoid that occurs in rose oil. 

Lipids have been dehned on the basis of their stmctnre and solnbility. Lipids are natnrally occnrring componnds consisting of fatty acids and their derivatives, bile acids, pigments, vitamins, and steroids, as well as terpenoids, which are usually soluble in organic solvents such as benzene, chloroform, ether, and alcohol, etc., with variable solubility depending on the stmctnre of the lipid compound. 

The repertoire of chemicals that can be used for communication is limited by the biosynthetic ability of the insect. Compared to other insect orders, pheromone biosynthesis in Hymenoptera has received little study [191]. However, the biosynthetic origins of chemically diverse hymenopteran semiochemicals likely include aromatic, fatty acid, and terpenoid pathways as well as simple modifications of host-derived precursors. Notable recent studies include the biosynthesis of the fatty acid components (2 )-9-oxodec-2-enoic acid 52 and (2 )-9-hydroxydec-2-enoic acid of the honeybee queen mandibular pheromone from octadecanoic acid [192,193], and the aliphatic alcohol and ester... 

Montan wax is obtained by solvent extraction of certain types of lignite or brown coal. It has a dark colour when not treated, but it is lighter when refined. Its chemical composition includes esters of C22 C32 acids (53%), free acids (17%), free alcohols (1 2%), ketones (3 6%) and terpenoids (20 23%) [85]. 

Silica gel successfully catalyzed the stereoselective synthesis of several glucoside terpenoids. Treatment of 49a with propan-2-ol, geraniol, the tetrahydropyranyl (THP) ether of coniferyl alcohol, and (—)-perillyl alcohol gave glucosides 52a-d in good yields (Scheme 12). The acid-labile THP group was retained under these reaction... 

Fig. 29 Formation of isomeric decalins [71 ]—[73] by cyclization of a terpenoid alcohol catalysed by antibody HA5-19A4 raised to hapten [82]. The transition state [83a] has the leaving group in the equatorial position, as favoured by the Stork-Eschenmoser...

Adults of some species also produce 4-oxo-( )-2-alkenals. Other types of simple compounds that have been found in the defensive secretions of true bugs include common terpenoids such as a- and (3-pinenes, limonene, linalool, and Z, -oc-farnesene, and simple aromatic compounds such as benzyl alcohol, ben-zaldehyde,p-hydroxybenzaldehyde, methyl p-hydroxybenzoate,phenylethanol, and guaicol. In general, although a number of species may share particular components, each species does appear to produce its own particular blend. In at least one species, the blend of defensive compounds is reported to vary with season and/or diet [36]. 

C8-C22 alkyl and alkenyl alcohols Alkyl acids and esters (16) Unidentified compounds possible terpenoid isomers and... 

Another heterocyclization is presented by Panifilow et al. Cyclic acetals and ethers are obtained by electrochemical oxidation of the terpenoid alcohol linalool 57 in methanol containing alkaline and sodium methoxide as electrolyt [102]. Anodic oxidation of the C(6)-C 7) double bond of linalool leads to the radical cation 58. In addition to direct methoxylation of the radical cation an attack on the hydroxyl group takes place. After a second one-electron oxidation and following methoxylation the regioisomeric cyclic acetal and a subsequent 1,2-hydride shift, the cyclic acetal 60 and the cyclic ether 61 are finally formed in yields of 16 and 24%, respectively (Scheme 13). As shown by Utley and co-workers bicyclic lactones 65 and 66 can be synthesized by anodic oxidation... 

The great diversity of terpenes helps to cormteract tolerance by herbivores. In all, terpenes are not very toxic to vertebrates. Many mammals ingest a significant amount of terpenoids with their diet. Monoterpenes from pine oil added to the diet reduces food intake in red deer, Cervuselaphus, calves (Elliot and Loudon, 1987). The brush-tailed possmn, Trichosurus vulpecula, detoxifies (-l-)-a-pinene to alcohol and carboxylic acid derivatives. 

Terpenes are polymers of the 5-carbon compound isoprene (Figure 1.12) and, as such, generally display properties similar to those of hydrocarbons. Terpenoids are substituted terpenes (i.e. contain additional chemical groups, such as an alcohol, phenols, aldehydes, ketones, etc.). Only a few such substances could be regarded as true drugs. Terpenes, such as limonene, menthol and camphor, form components of various essential oils with pseudo-pharmaceutical uses. A number of these molecules, however, exhibit anti-tumour activity, of which taxol is by far the most important. 

Proc Okla Acad Sci 1974 54 34-35. Demole, E., and C. Demole. A chemical study of hurley tobacco flavour Nicotiarui tabacum). VII. Identification and synthesis of twelve irregular terpenoids related to solanone, including 7,8-dioxabicycIo[3,2,l]-octane and 4,9-dioxabicycIo[3.3.1 Jnonane derivatives. Helv Chim Acta 1975 58 1867. Bharadwaj, B. V., S. Takayama, T. Yamada, and A. Tanimura. N -nitro-sonornicotine in Japanese tobacco products. Gann 1975 66 585. Randolph, H. R. Gas chromatographic determination of nicotine in an isopropyl alcohol extract of smoke particulate matter. Tobacco 1974 176 44-Yung, K. H., and D. H. Northcote. Enzymes in the walls of mesophyll cells of tobacco leaves. Biochem J 1975 151 141. 

G.l.c. papers of interest include the classification of 22 acyclic monoterpenoid alcohols according to retention indexes, resolution of cyclic ketones [e.g. ( )-menthone, ( )-isomenthone] as diethyl (+)-tartrate acetals, and the use of lanthanide shift reagents to resolve non-terpenoid racemic epoxides.The occurrence and prevention of monoterpenoid hydrocarbon isomerization during silica gel chromatography has been examined and the separation of monoterpenoids and sesquiterpenoids by gel permeation chromatography is reported. Monoterpenoid hydrocarbons have been selectively extracted from essential oils using dimethylsilicone. ... 

Chiral l,3-dioxin-4-ones photochemically react intermolecular with (cyclic) ethers, acetals, and secondary alcohols to give the addition products in reasonable yields. The radical addition was completely stereoselective at C-6 of the heterocycle <1999EJO1057>. The exocyclic diastereoselectivity, where relevant, was about 2 1 (Equation 30). In analogy, an intramolecular cascade reaction of a 1,3-dioxin -one derived from menthone was used to get a terpenoid or a steroid framework in optically active form <1997JA1129, 1999JA4894>. 

Essential oils may comprise volatile compounds of terpenoid or non-terpe-noid origin. All of them are hydrocarbons and their oxygenated derivatives. Some may also contain nitrogen or sulphur derivatives. They may exist in the form of alcohols, acids, esters, epoxides, aldehydes, ketones, amines, sulphides, etc. Monoterpenes, sesquiterpenes and even diterpenes constitute the composition of many essential oils. In addition, phenylpropanoids, fatty acids and their esters, or their decomposition products are also encountered as volatiles [1-16, 21-33, 36-38]. 

Non-terpenoid hydrocarbons found in essential oils such as short chain alcohols and aldehydes are formed by metabolic conversion or degradation of phospholipids and fatty acids [12]. 

Aromatic monoterpenes which contain a benzene ring like p-cymene 9, car-vacrol 12, thymol 13 and phenylethyl alcohol 14 (Structure 4.4) are common constituents of many essential oils, e.g. oregano (Origanum sp.), thyme (Thymus sp.), savory (Satureja sp.) and rose (Rosa sp.) oils. Another important constituent class of essential oils is phenypropanoids [36]. They are not considered as terpenoids owing to their different biogenetic origins, which will be mentioned later. 

Heating (cooking) seems to produce certain terpenoids. In some vegetables, such as tomatoes and potatoes, there is a considerable increase in the formation of some terpene alcohols, including linalool, a-terpineol and terpinen-4-ol during heat treatments. 

The berry or the small fruits consist of strawberry, raspberry, blackberry, black currant, blueberry, cranberry and elderberry. The volatiles responsible for the flavour of small fruits are esters, alcohols, ketones, aldehydes, terpenoids, furanones and sulfur compounds (Table 7.3, Figs. 7.1-7.7). As fruit ripen, the concentration of aroma volatiles rapidly increases, closely following pigment formation [43]. 

Sugars, acids and aroma compounds contribute to the characteristic strawberry flavour [85]. Over 360 different volatile compounds have been identified in strawberry fruit [35]. Strawberry aroma is composed predominately of esters (25-90% of the total volatile mass in ripe strawberry fruit) with alcohols, ketones, lactones and aldehydes being present in smaller quantities [85]. Esters provide a fruity and floral characteristic to the aroma [35,86], but aldehydes and furanones also contribute to the strawberry aroma [85, 87]. Terpenoids and sulfur compounds may also have a significant impact on the characteristic strawberry fruit aroma although they normally only make up a small portion of the strawberry volatile compounds [88, 89]. Sulfur compounds, e.g. methanethiol. 

Approximately 230 volatile compounds have been identified in raspberry fruit [35]. The aroma of raspberries is composed of a mixture of ketones and aldehydes (27%) and terpenoids (30%), alcohols (23%), esters (13%) and furanones (5%). The raspberry ketone (Fig. 7.5) along with a-ionone and jS-ionone have been found to be the primary character-impact compounds in raspberries. Other compounds such as benzyl alcohol, (Z)-3-hexen-l-ol, acetic acid, linalool, geraniol, a-pinene, jS-pinene, a-phellandrene, jS-phellandrene and jS-caryophyllene contribute to the overall aroma of mature red raspberries [101-105]. The most important character-impact compounds of raspberries are summarised in Table 7.3. 

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