Sesquiterpenes classification

Staroscik and Wilson ] ) have analyzed various lemon oils and identified 38 compounds. These compounds can be subdivided into three major classifications terpenes (C10 hydrocarbons), oxy fraction (oxygenated C8-C12 hydrocarbons), and sesquiterpenes (Cls hydrocarbons). Lemon oil is usually concentrated to remove the terpenes and sesquiterpenes from the desired Ce-Cl2 oxy fraction (8). 

Isoprene has the chemical formula of C5H8, therefore, each isoprene unit correlates to five carbons present in the skeleton. Terpene classification includes hemiter-penes, monoterpenes, sesquiterpenes, diterpenes, sesterterpenes, and triterpenes, each consisting of one through six isoprene units, respectively [16]. Additional terpene classifications include tetraterpenes, containing eight isoprene units, and polyterpenes, which include isoprene chains. The classification system is further divided into subclasses [15]. 

Hristozov, D., Da Costa, F.B. and Gasteiger, J. (2007) Sesquiterpene lactones-based classification of the family Asteraceae using neural networks and fe-nearest neighbors. /. Chem. Inf. Model., 47, 9—19. 

Classification Sesquiterpene derived from essential oils Empirical C15H26... 

Costa FB, Terfloth L, Gasteiger J (2005) Sesquiterpene lactone based classification of three asteraceae tribes a study based on self-organizing neural networks applied to chemosys-tematics. Phytochemistry 66 345... 

Terpenes are defined and classified by the so-called isoprene rule, introduced by Wallach in 1887 [22]. Two isoprene units make one terpene unit. They are grouped according to the number of isoprene units, for example, mono terpenes [Ciol. sesquiterpenes [C15], diterpenes [C20], triterpenes [C30], and tetraterpenes [C40] contain 2, 3, 4, 6, and 8 isoprene units, respectively. A subsidiary classification is based on the number of carbon rings present in the terpene ... 

MVA and DXP biosynthetic pathways provide the essential active isopropene units in the form of IPP and DMAPP for the construction of natural terpenoids. Following this introduction, terpenoids have been organized in accordance to their major classifications into four subchapters, monoterpenes, sesquiterpenes, diterpenes, and higher terpenes. In each of these chapters, a detailed biosynthetic analysis is attempted. Thus, the current chapter serves only as an introduction and by any mean does not serve as an exhaustive review on the topic of mevalonic and deoxyxylulose biosynthetic pathways. 

It is possible to refine the classification of terpenes as described by Bergquist and Wells by adding other terpenes and meroterpenes. Table 19.40 shows the distribution of 350 terpenes currently isolated from Dendroceratida divided into the six classes of Bergquist and Wells, to which have been added sesquiterpenes (T15), diterpenes (T20), sesterterpenes (T25) and meroterpenes (M), the... 

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