Terpenoid polymerization

Uses ndReactions. a-Pinene (8) is useful for synthesizing a wide variety of terpenoids. Hydration to pine oil, acid-catalyzed isomerization to camphene, thermal isomerization to ocimene and aHoocimene, and polymerization to terpene resins are some of its direct uses. Manufacture of linalool, nerol, and geraniol has become an economically important use of a-pinene. 

Terpenoid (Chapter 6 Focus On. Section 27.5) A lipid that is formally derived by head-to-tail polymerization of iso-prene units. 

P-parinaric acid, physical properties, 5 33t P-pentenoic acid, physical properties, 5 3 It P-peroxylactones, 18 484 Beta phase titanium, 24 838 in alloys, 24 854-856 properties of, 24 840, 941 P-phellandrene, 24 493 P-picoline, 21 110 from acrolein, 1 276 uses for, 21 120 P-pinene, 3 230 24 496-497 major products from, 24 478 /-menthol from, 24 522 as natural precursor for aroma chemicals, 3 232 terpenoids from, 24 478-479 P-propiolactone, polymerization of, 14 259 P-quartz solid solution, 12 637—638 Beta ratio, in filtration, 11 329—330 Beta (P) rays, 21 285 P-scission reactions, 14 280-281 P-skytanthine, 2 101 P-spodumene solid solution, 12 638-639 P-sulfur trioxide, 23 756 P-sultones, 23 527 P-tocopherol, 25 793 P-tocotrienol, 25 793 P-vinylacrylic acid, physical properties, 5 33t... 

Wood resin is considerably changed during the pulping process. The fatty acid esters of sterols and triterpenoid alcohols in hardwoods (waxes) are saponified very slowly. Unsaturated compounds, e.g., fatty acids, resin acids, and other higher terpenoids, are polymerized to high molecular weight compounds, which also give rise to "pitch problems."... 

The isoprene unit is the most important building block for lipids, steroids, terpenoids, and a wide variety of natural products. The only chemical reaction of commercial importance (other than polymerization) is its conversion to terpenes. Isoprene is used in the manufacture of synthetic natural rubber, butyl rubber, and as a copolymer in the production of synthetic elastomers. 

Amber (succinite). General term for fossilized terpenoid resins from the Tertiary period formed from resinous secretions of coniferous trees. They owe their hardness and poor solubility to the evaporation of volatile terpenes as well as to autoxidation and polymerization of resin acids and alcohols. The resin alcohols are mostly esterified with succinic acid. - [HS253090]... 

However, there seems to be a change in judging the situation and due to the development of new techniques, such as highly efficient post-polymerization modification techniques such as dick chemistry. The recent state in the field of terpenes, terpenoids, and rosin has been reviewed. These t5q>es of biomass are of low cost, and have much potential for their utilization as organic feedstocks for green plastics. 

The stereochemistry is well established, and many questions concerning the overall mechanism of the condensation have now been resolved. Famesyl pyrophosphate synthetase (EC 2.5.1.1) is the key enzyme in the biosynthetic pathways for several classes of terpenes. This enzyme catalyzes l -4 condensation between IPP and DMAPP, or geranyl pyrophosphate, polymerizations that constitute the major building steps of terpenoid biosynthesis (Fig. 21.2) (Poulter and Rilling, 1978 Poulter et al., 1978, 1981). The condensation... 

Terpenoids are classified by the number of five-carlxMi units they contain like hemiterpenes (C5), monoterpenes (Cio), sesquiterpenes (C15), diterpenes (C20), triterpenes (C30), tetraterpenes (C40), and polyterpenes (more than 8 isoprene units). All terpenoids are derived by repetitive fusion of branched five-carbon units based on isopentane skeleton, i.e., isoprene units. At suitable chemical conditions, isoprene undergoes polymerization to generate numerous terpenoid skeletons. 

The various compounds responsible for the decay resistance of heartwood, their structures, their biosynthesis, and their chemotaxonomy are discussed in Chaps. 7 and 8. Most of the important antimicrobial compounds are phenolics, although the terpenoids may also be involved. Often the major portion of the phenolic extractives are polymeric materials (MW > 500) that cannot be identified. These materials may be very important in increasing the durability of heartwood but little work has been reported. 

The elementary reactions in polypeptide synthesis are the amino acid (monomer) activation step followed by initiation, propagation, termination and release. Also, the exact mechanism of most of the biological polymerizations is not known. The exception is short-chain terpenoid biosynthesis, which we will discuss in Chapter 4. However, Yokoza-wa s general mechanism also applies to protein biosynthesis. The final steps, folding and post-translational processing are unique to protein synthesis synthetic pol mer chemists have not yet been able to master these unique processes. 

DMAPP may serve as the initiator for subsequent terpenoid synthesis (chain growth or polymerization) catalyzed by appropriate enzymes. These elementary reactions will be discussed in detail in the synthesis section. For the chemical understanding of the compounds, we use -OPP to denote pyrophosphate groups. In the biological literature, the pyrophosphate group is typically written as -PPi. 

Why is terpenoid bios5Uithesis considered to be a combination of chain growth and condensation polymerization ... 

Isomerase enzyme modifies the building block in such a way that it can serve as initiator for the reaction. The dimethylal-lyl pyrophosphate is activated and serves as initiator for the polymerization of terpenoids. Initiator is essential for any polymerization ... 

Terpenoid biosynthesis is a carbocationic polymerization, combining step-growth and chain-growth. 

During chain growth polymerization only the monomer units are added to the active chain end, without any byproduct. Condensation polymerization has byproduct and the polymerization proceeds by the addition of oligomers. The terpenoid synthesis has both characteristics only monomers are added to the chain end, however byproduct is produced during the polymerization. 

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