Terpenes di- 332

Af-Chlorosuccinimide is the most widely used reagent for the chlorination of P-ketophosphonates and l-(alkoxycarbonyl)methylphosphonates to give structures that are often incorporated into complex carbacyclins, - prostaglandins, or bicyclic sesqui- and di terpenes. The reaction takes place in the presence of NaH (2 eq) in DME or I HL at room temperature, and the resulting chlorinated carbanions are allowed to react in situ with the appropriate carbonyl compounds to give the desired chloroolefins in 38-80% yields. ... 

C22H33NO20, Mr 343.51, resin, [a]o-21° (C2H5OH) di-terpene alkaloid from Aconitum hetemphyllum, A. gigans, and A. anthara. 

C20H26O6. Mr 362.42, mp. 297-299°C decomp., [aJo -131.3° (pyridine), a diterpene of the kaurane type bitter principle from Rabdosia trichocarpa and R. ja-ponica shows antitumor and anti-inflammatory activity against Ehrlich ascites tumors and inhibits insect growth. E. can be transformed into numerous other di-terpenes such as abietanes, Aconitum alkaloids, gib-berellins. The biosynthesis proceeds from 16-kaurene. Lit. Agric. Biol. Chem. 43, 71 (1979) Karrer, No. 3712 Zechmeister 46, 77-157. - (CAS3776-39-4]... 

C34H4JO8, Mr 584.75, [aJo +55.1 (CHCI3), a toxic di-terpene with daphnetoxin structure from Hura crepitans (Euphorbiaceae). H. irritates the eyes and skin and can lead to blindness. As a fish toxin H. is ten times more potent than rotenone. It has insecticidal activity. Lit. J. Nat. Prod. 47, 482 (1984) Phytochemistry 32, 141 (1993). - [CAS 33465-16-6]... 

Balsam T Produced by steam distillation from the oil-containing resin (balsamic resin, turpentine), secreted from the trunks of pine trees as pathological symptom (wound balsam) when the outer wood layer is injured. The residue is colophony consisting of di-terpene resin acids. 

Qsclareol belongs to the sizable class of labdanoid di-terpenes. The name is derived from labdanum, a resin found in certain rock rose (Cistus) species, from which the first member with this core structure was isolated. 

Structure. T. are subdivided according to the number of Cj units in their structure, i.e. Hemiterpenes (see), Monoterpenes (see). Sesquiterpenes (see), Di-terpenes (see), Sesterterpenes (see), Triterpenes... 

Dopaminergic compounds in the fruits with in vitro prolactin-suppressive activity are di-terpenes, including rotundifuran and others (clerodadienols). ... 

Contains 0.3-1% of a bitter principle called marrubiin (a diterpene lactone) several di-terpene alcohols (e.g., marrubiol, marrubenol, peregrinol, and vulgarol) small amounts of alkaloids (ca. 0.3% betonicine, its stereoisomer turicine, and ca. 0.2% choline) trace of a volatile oil containing monoterpenes (a-pinene, camphene, limonene, sabinene. 

Organic sulfur compounds such as sulfurized spermaceti oil, terpene sulfides, and aromatic disulfides have been used. Encumbered phenols such as di-tertiary-butylphenols and amines of the phenyl-alphanaphthylamine type are effective stopping the kinetic oxidation chain by creating stable radicals. 

This hydrocarbon, also known as nor-camphene, is an immediate lower homologue of the terpenes, of the formula It was dis-... 

From a chemical point of view, vegetable resins are a complex mixture of mono-, sesqui-, di- and triterpenes, which have, respectively, 10, 15, 20 and 30 carbon atoms per molecule. The mono- and sesquiterpenes are both present in most resins. The di- and triterpenes are rarely found together in the same resin, which means that terpenic resins can be divided into two main classes. Table 1.5 lists the botanical origin and the kind of terpenoid compounds of some natural resins. 

Almost a third of the reported brown algal chemistry comes from a single genus, Dictyota, which has elaborated a wealth of terpenes (>250) (Munro and Blunt 2005). Diterpenes dominate Dictyota chemistry and are typically di- and tricyclized, as seen in dictyol E (Fig. 1.6a) (Danise et al. 1977), amijiol (Fig. 1.6b) (Ochi et al. 1980), Fig. 1.6c (Tringali et al. 1984), and dictyoxetane (Fig. 1.6d) (Pullaiah et al. 1985). 

German for turpentine) and there are approximately 15000 terpenes. Terpenes are lipophilic, and the building blocks are five-carbon units with the branched carbon skeleton of isopentane. The basic units are sometimes called isoprene (F ig. 11.5fl), because heat decomposes terpenoids to isoprene. Depending on the number of C5 units fused, we distinguish mono- (Cio), sesqui- (C15), di- (C20), tri-(C30), tetra- (C40) and polyterpenoids [(Cs) , with n > 8]. Alpha-Pinene and bor-neol (Fig. 11.56) are examples of monoterpenes. 

Since the early times of stereochemistry, the phenomena related to chirality ( dis-symetrie moleculaire, as originally stated by Pasteur) have been treated or referred to as enantiomericaUy pure compounds. For a long time the measurement of specific rotations has been the only tool to evaluate the enantiomer distribution of an enantioimpure sample hence the expressions optical purity and optical antipodes. The usefulness of chiral assistance (natural products, circularly polarized light, etc.) for the preparation of optically active compounds, by either resolution or asymmetric synthesis, has been recognized by Pasteur, Le Bel, and van t Hoff. The first chiral auxiliaries selected for asymmetric synthesis were alkaloids such as quinine or some terpenes. Natural products with several asymmetric centers are usually enantiopure or close to 100% ee. With the necessity to devise new routes to enantiopure compounds, many simple or complex auxiliaries have been prepared from natural products or from resolved materials. Often the authors tried to get the highest enantiomeric excess values possible for the chiral auxiliaries before using them for asymmetric reactions. When a chiral reagent or catalyst could not be prepared enantiomericaUy pure, the enantiomeric excess (ee) of the product was assumed to be a minimum value or was corrected by the ee of the chiral auxiliary. The experimental data measured by polarimetry or spectroscopic methods are conveniently expressed by enantiomeric excess and enantiomeric... 

Closely related to the synthetic work reported in the previous section is the incorporation (131) of a 2,5-anhydro-3,4Hdi-0-methyl-D-mannitol residue (Figure 15) into the 18-crown-6 derivative d-91. Other derivatives of D-mannitol that have been built into crown ether receptors include l,4 3,6-dianhydro-D-maiuiitol (132), l,3 4,6-di-0-methylene-D-marmitol (13 134), and 1,3 4,6-di-O-benzylidene-D-mannitol (134). Examples of chiral crown compounds containing these residues include dd-92, dd-93, d-94, and d-95. Although not derived from carbohydrates—but rather (135) from the terpene, (-t-)-pulegone—... 

Pinane Group (Bicyclo [3.1.1]heptane Type) The pinane-type bicyclic terpene hydrocarbons will be named as pinanes, pinenes, and pinadienes, and these names will be based on the recommended fixed numberings of the pinane carbon skeleton (see Formula IV). For those derivatives which contain (1) fewer carbon atoms than pinane, (2) the same number as, or more carbon atoms than, pinane but do not have a carbon skeleton identical with that of pinane, or (3) more carbon atoms than pinane and a carbon skeleton identical with that of pinane but contain substituents such that the principle of like treatment of like things will be violated by using the pinane, pinene, and pinadiene names, the nor- type of terpene names based on systematic bicyclo numbering will be used (see Formula VII). Examples 2(10),3-pinadiene, 4-methylenepinane, 6,6-di-methyl-2-vinyl-2-norpinene. 

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