Terpenoid esters

A terpenoid ester for gastro-duodenal ulcer gefamate 46... 

The oils have a high terpene hydrocarbon content (>90%, mainly (+)-limonene), but their content of oxygen-containing compounds differs and affects their quality. Important for aroma are aldehydes, mainly decanal and citral, and aliphatic and terpenoid esters. The sesquiterpene aldehydes a-sinensal [17909-77-2] and/3-sinensal [6066-88-8], which contribute particularly to the special sweet orange aroma, also occur in other citrus oils, although in lower concentration [369-370a, 370d, 394,421, 430-438]. 

Table 14.5 shows that with few exceptions each species appears to contain a unique blend of terpenoid esters as defined by its molecular composition and/ or the relative concentration of each component. Such a tendency to species-specificity is not suggested in the Colletidae or Halictidae, the only other families for which there are enough examples to draw any conclusions. 

Duffield, R. M., Harrison, S. E., Maglott, D., Ayorinde, F. O. and Wheeler, J. W. (1983) Exocrine secretions of bees V. Terpenoid esters in the Dufour s secretions of Panurginus bees (Hymenoptera Andrenidae). J. Chem. Ecol.y 9, 211-S3. 

Terpenoid esters occur in various fruits and many spices. Examples are the fairly widespread geranyl (8-80) and neryl acetates (8-81), which are components of citrus oils and odours of some spices (such as coriander). 

Unsaturated Esters.—A simple, stereoselective route to terpenoid esters, i.e. ( )-3-methylalk-2-enoates, is by zirconium-catalysed carboalumination of terminal acetylenes, illustrated in Scheme 38 for the preparation of ethyl geranoate in 78% isolated yield. In common with related vinylcuprates, the... 

Similarly to alkenes. alkynes also insert. In the reaction of 775 carried out under a CO atmosphere in AcOH, sequential insertions of alkyne, CO. alkene. and CO take place in this order, yielding the keto ester 776[483]. However, the same reaction carried out in THF in the presence of LiCl affords the ketone 777, but not the keto ester[484]. The tricyclic terpenoid hirsutene (779) has been synthesized via the Pd-catalyzed metallo-ene carbonylation reaction of 778 with 85% diastereoselectivity as the key reaction[485], Kainic acid and allo-kainic acid (783) have been synthesized by the intramolecular insertion ol an alkene in 780, followed by carbonylation to give 781 and 782[486],... 

Some examples of conjugate addition reactions of allylic silanes are given in Scheme 9.5. Entries 1 to 3 illustrate the synthesis of several (3-allyl ketones. Note that Entry 2 involves the creation of a quaternary carbon. Entry 4 was used in the synthesis of a terpenoid ketone, (+)-nootkatone. Entry 5 illustrates fluoride-mediated addition using tetrabutylammonium fluoride. These conditions were found to be especially effective for unsaturated esters. In Entry 6, the addition is from the convex face of the ring system. Entry 7 illustrates a ring closure by intramolecular conjugate addition. 

A hypothetical structural model developed by Yen (24) represented the organic components of Green River oil shale. The major components were isoprenoids, steroids, terpenoids and cartenoids. The common bridges consisted of disulfide, ether, ester, heterocyclic and alkadiene. Elemental analysis of typical oil shale samples has shown... 

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]. 

Vinyl phosphonates have been used in the construction of valerenic acid terpenoids 169 (Scheme 42).101 Both five-and six-membered rings can be formed via the vinyl phosphonate Alder-ene reaction which can be catalyzed by a variety of Lewis acids. The resulting structures 167 are suitable for Wittig-Horner reaction to give diene 168. Subsequent reactions access valerenic acid terpenoids 169. The chirality of the carbon bearing the phosphonate and ester is transferred, but is subsequently lost in the Wittig-Horner step. 

Terpenoid pheromones, 24 473 Terpenoid skeletons, 24 469 biosynthesis of, 24 471 Terpin hydrate, 3 231 a-Terpineol, 24 477, 509-512, 3 231 hydrogenation of, 24 512 a-Terpinyl acetate, 24 512 a-Terpinyl chlorides, 24 479 a-Terpinyl esters, 3 231 y-Terpinene, 3 230 Terpinolene, 24 493 Terpolymers... 

Ubiquitous in seeds is phytic acid, the hexaphosphate ester of inositol, which has been isolated from cucurbit seeds (57). Small amounts of free sugars and terpenoid glycosides (cucurbitacins) are also present (58-60), but starch is absent (1, 1). Cellulosic cell wall materials comprise the remaining carbohydrate content. 

The earliest synthetic resin to be used in commerce seems to have been a polyester then termed ester gum, which was made by esterifying rosin (essentially an unsaturated monocarboxylic terpenoid acid, abietic acid) with glycerol. When cooked with tung oil (a glycerol ester of 9,11,13-octadecatrienoic acid), this provided varnishes that dried overnight. In this case, the polymer is formed by an addition copolymerisation process, but the product is nevertheless also a polyester. 

Even more complex potential prodrugs of indomethacin were examined, namely its limonenyl, perillyl, bomyl, and menthyl esters, i. e., terpenoid derivatives [21]. These highly lipophilic esters showed rapid enzymatic hydrolysis, and the limonenyl prodrug assayed in humans had an interesting delayed and sustained cutaneous anti-inflammatory activity. 

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

Figure 6. MTPA ester of marine terpenoid sipholenol (partial structure). No correlation of all separated H signals required by Kakisawa s model.

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