Terpenes classes

Collection site Terpene class Acyclic Cyclic Reference... 

Terpenes are classified by the number of isoprene units they contain. A monoterpene contains 10 carbons and has two isoprene units, a sesquiterpene contains 15 carbons and has three isoprene units, and. so forth. The different terpene classes are summarized in Table 29.5. 

The biosphere is a major contributor to the atmosphere of heavier hydrocarbons. Fritz Went (8, 9), who first recognized the global extent of smog, pointed out the general importance of natural emissions from vegetation. He estimated that sources in the biosphere annually emit between 170 X 10 and 10 tons of hydrocarbon material to the atmosphere. Went also observed that these materials are mainly in the terpene class and that, because they are photochemically reactive, these materials are polymerized in atmospheric photochemical reactions to form an organic aerosol. He attributes the blue haze found in many forested areas to the optical effects of this aerosol. 

However, oils occur in much greater concentrations in fruits and seeds. The so-called essential oils are usually sweet, or aromatic smelling organic compounds which may also contain sulfur and nitrogen in addition to the usual carbon and hydrogen. These oils are often of the terpene class with the general formula (C5Hg) , where n > 1, or may be compound types similar to camphor or other oxidation products associated with the basic terpene structure. 

As the PSA industry evolved, natural rubber (NR) and styrene-butadiene rubber (SBR) were the primary elastomers used. Other backbone polymers were available but were used to a lesser degree. These other elastomers include polychloroprene, butyl rubber and nitrile rubber. Traditionally, formulations containing natural rubber have made use of polyterpene resins as tackifiers, particularly beta-pinene resins. The probable structure of a beta-pinene resin is given as follows and represents the terpene class of resins. 

Terpene alcohol Mixing terpene alcohol and terpenes Class A terpene alcohol >60 % Class B 0 terpene alcohol >50 % Class B terpene alcohol >40 % Boiling point 168 °C Moisture content 2.5 % ... 

Differences in total concentration of distinct terpene classes, i.e. the monoterpenes and norisoprenoids, that were released from the glycosidic precursors of the varieties Chardonnay and Sauvignon Blanc, were discussed in Section 3.3.2. It is evident that with extension of this approach to other non-floral varieties (Versini et al. 1988 Razimgles et al. 1993) the reliability of distinguishing compositional data is likely to be further established. 

Wallach, Otto (1847-1931) German chemist who studied volatile oils and, from this work, established and named the terpene class of compounds. He showed that the terpenes consisted of a variable number of five-carbon units, each of which was called an isoprene unit. He was awarded the 1910 Nobel Prize in chemistry. 

Terpenes Classes - Occurrence, Biosynthesis, Structure and Chemistry, Distribution... 

Drug LogR of drug Terpene Log P of terpene Class and type of terpene Ref. 

Stereoparents are derived from the common names of natural products. The following discussion focuses on stereoparents from the steroid, alkaloid or terpene classes. The stereoparent is the simplest member of a family of related, cyclic structures with complex stereochemistry. The stereochemistry is given by a stereospecific structure diagram which appears in the CA Chemical Substance Index this is illustrated by cholestane (Figure 4). Stereochemistry is indicated in the diagram by dotted lines (a bonds), if the substituent is below the plane of the ring, and wedged lines O bonds), if it is above the plane. 

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