Identification terpene

In those cases where a laboratory is routinely handling natural products that have been seen before in the same laboratory, a self-constructed library of mass spectra is a valuable aid to identification. Such a system is particularly useful in the GC/MS analysis of body fluids (in biomedical research and clinical diagnosis) and in the perfume and flavor industries e.g. terpene identification). Metabolic profiling by GC/MS 48) of the components of urine or serum provides an instance where computer techniques are a necessity and have become quite sophisticated. 

The identification of camphene is best carried out by its conversion into isobomeol under the influence of acetic acid in the presence of sulphuric acid. In order to effect this conversion, 100 grams of the fraction containing the terpene in substantial quantity are mixed with 250 grains of glacial acetic acid and 10 grams of 50 per cent, sulphuric acid. Tne mixture is heated for two to three hours on a water-bath to a temperature of 50° to 60°. At first the liquid separates into two layers, bat soon becomes homogeneous and takes on a pale red colour. Excess of water is added, and the oil which is precipitated, and which contains the isobomeol in the form of its acetate, is well washed with water repeatedly. It is then saponified by heating with alcoholic potash solution on a water-bath. The liquid is then evaporated and extracted with water, and the residue recrystallised from petroleum ether. 

To prepare sabinenic acid for the identification of the terpene, Wallach operates as follows 10 grams of the crude terpene are mixed with the theoretical amount of potassium permanganate in water at ice temperature. The oxide of manganese is filtered off, the liquid rendered acid and extracted with ether, and the ethereal solution shaken with caustic soda solution. The sodium salt is very sparingly soluble, and is precipitated, collected, and decomposed with dilute sulphuric acid and purified by a further solution in ether. It must be well dried in a desiccator before its melting-point is determined. Sabinene has the following constitution —... 

For the identification of terpinolene, its tetrabromide is the most characteristic compound. This body is prepared by adding gradually four atoms of bromine to a solution of the terpene in glacial acetic acid, maintained at a low temperature. Terpinolene tetrabromide, C], Hj,.Br., melts at 116° to 117°, when recrystallised from alcohol. 

The isolation of four terpenes from the bitter principles of Ginkgo by Furukawa in 19326 marked an important advance in the quest for the identification of the active constituents of Ginkgo extracts. A second major milestone was reached in 1967 when Nakanishi and his group reported their extensive and brilliant studies which permitted the structures of these compounds to be fully defined.4 On the basis of spectroscopic data and chemical reactivity... 

Species of Bazzania have been shown to be a rich source of terpene derivatives. Bazzania trilobata is no exception as evidenced by the identification of no less than 44 compounds from European collections, and 29 from plants collected in North America (Warmers and Konig, 1999). The major differences between plants from the two sides... 

After identification of A9-THC as the major active compound in Cannabis and its structural elucidation by Mechoulam and Gaoni in 1964 [66], a lot of work was invested in chemical synthesis of this substance. Analogous to the biosynthesis of cannabinoids, the central step in most of the A9-THC syntheses routes is the reaction of a terpene with a resorcin derivate (e.g., olivetol). Many different compounds were employed as terpenoid compounds, for example citral [67], verbenol [68], or chrysanthenol [69]. The employment of optically pure precursors is inevitable to get the desired (-)-trans-A9-THC. 

SPME/GC/MS is an efficient technique to reveal the presence of resinic substances in archaeological samples. Indeed, volatile terpenes are still present in very old archaeological samples (4000 years old), particularly in the case of compact matrixes, and can be trapped by the SPME fibre. In comparison with methylene chloride extraction, SPME is very specific and allows the direct analysis of the volatile terpenes content in complex mixtures including oils, fats or waxes. For this reason, headspace SPME is the first method to use when analysing an archaeological sample it will either allow the identification of the resin or indicate further sample treatment in order to detect characteristic triterpenes. The method is not really nondestructive because it uses a little of the sample but the same sample can be used for several SPME extractions and then for other chemical treatments. 

The analytical technique of choice for the identification of low molecular weight terpenes and terpenoids is GC/MS, assisted by off-line methylation or silylation reactions. However, comparable results in terms of sensitivity and response specificity... 

Table 11.1). In both cases, (ii)-nerolidol was not detected or found only in traces in the volatile blend, indicating a rapid conversion of this terpene alcohol into DMNT. Despite finding nerolidol synthase activities, the identification of the respective genes involved in DMNT formation has lagged behind. Schnee et al. 

Studies on HPLC with iridoids of Apoc)maceae focus mainly on the separation of components from extracts or fraction. The chromatography profile, the identification and quantification of these terpenes in the extracts are described. Table 4 shows the principal references on iridoids isolated from Apoc)maceae by HPLC, MPLC and LPLC. 

Renwick J. A. A. (1967) Identification of two oxygenated terpenes from the bark beetles Dendroctonus frontalis and Dendroctonus brevicomis. Contrib. Boyce Thompson Inst, of Plant Res. 23, 355-360. 

Silverstein R. M., Rodin J. O., Wood D. L. and Browne L. E. (1966b) Identification of the two new terpene alcohols from frass produced by Ips confusus in ponderosa pine. Tetrahedron 22, 1929-1936. 

The reaction was later widely used by Wallach for the identification of terpenes, which formed well defined, crystalline nitrosates and nitrosites and also by Jagelki [75] and Lipp [3],... 

For this sample the results show identification of 13 major components out of 289, making up 81.25% of the total components. The volatile monoterpene -pinene (peak 1) is the first off the column. The alcohols citronellol (10) and geraniol (11) are responsible for the odour characteristics of geranium, which is lifted and activated by the two rose oxides (2 and 3). The 6,9-guaiadiene (7) is a non-terpene hydrocarbon that acts as a back note but it is not a powerful odour. Component 12 is geranyl butyrate component 13 is epi—eudesmol. Chromatograms and data supplied by Jenny Warden of Traceability. 

In subsequent studies the simple terpenes EJi-a- and -/3-farnesene (3 8 and 39, respectively) were identified in dominant male urine.128 These odoriferous terpenes had long been recognized as components of cues released by a variety of other organisms (red fire ants, aphids, wild potato plants, fruit flies, and springbok). Because neither was detected in male bladder urine, attention was focused on the preputial glands as the source. Volatile components from dissected, fat-free preputial glands of dominant male mice were, again, preconcentrated on Ten ax. Subsequent GC analysis readily allowed identification of known 37 and 38. None of the earlier two components 36 or 37 was observed in the preputial volatiles, but both were present in the bladder urine of the same animals. 

Later in 1997, Ondeyka et a/.83 reported the isolation and identification of the structure of nodulisporic acid (27) using micro-NMR probe technology. Nod-ulisporic acid is a novel insecticide from Nodulisporium sp. and was the first representative of a new class of indole terpenes to be identified. The authors used a combination of -detected homo- and heteronuclear 2D-NMR experiments to assemble the structure in conjunction with a series of three INADEQUATE, each 5 days long, optimized from 40 to 60 Hz that employed a 26 mg sample of 27. The INADEQUATE data were subjected to computer analysis,84 86 which identified 32 of 47 possible 13C-13C connectivities. 

Martin DM, Bohlmann J. Identification of Vitis vinifera (-)-alpha-terpineol synthase by in silico screening of full-length cDNA ESTs and functional characterization of recombinant terpene synthase. Phytochemistry 2004 65 1223-1229. 

Oprean, R. Oprean, L. Tamas, M. Sandulescu, R. Roman, L. Essential oils analysis. II. Mass spectra identification of terpene and phenylpropane derivatives. J. Pharm. Biomed. Anal. 2001, 24, 1163-1168. 

Use Oxidant in special fuel systems, identification of terpenes, preparation of pure alkali nitrites. 

Terpenes Pitches and resins Gums, resins binders Identification and... 

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