Sesquiterpenes acetylenic

Fenical, W., Sims, J.J., and Radlick, P. (1973) Chondriol, a halogenated sesquiterpene acetylene from the marine alga Chondria oppositiclada Dawson. Tetrahedron Lett., 14, 313-316. 

Fraction 2 and 3 (P.E.) provided, besides the sesquiterpene hydrocarbon mixture, a compound which on the basis of H NMR and MS spectral evidence was shown to be the acetylenic hydrocarbon pentayneene (9) C,Ht> previously isolated from A. artemisiifolia... 

N.A. Carduus benedita L. Lignins, sesquiterpene lactones (cnicin), volatile oil, poly acetylenes.98 99 Stimulate the secretions of the stomach, intestines, gallbladder. 

Since the importance of sesquiterpenes, sesquiterpene lactones and flavonoids from the chemosystematic and the biological point of views, especially the chemistry and the biological activities of these compounds will be reviewed in this chapter, while the essential oils and the acetylenic compounds will not be mentioned. 

Yet another family producing polyacetylenes is the Composltae two acetylenics safynol and dehydrosafynol are formed in the diseased safflower (24). Our own experiments at Reading Indicate that acetylenes are formed In other members. This is however a very large family and other responses have been detected as well. TVo sesquiterpene lactones have been encountered as phytoalexins In Lac-tuca (25) while coumarins are reported as such In the sunflower Hellanthus annuus (26) ... 

Acetylenic carbinols, which are manufactured from aldehydes or ketones and acetylenes, can be partially hydrogenated, with the exception of propargyl alcohol itself. Hydrogenolysis is a minor side reaction unless the hydrogenation is completed to the alkane. Nickel boride (PI or P2) catalysts achieve the saturation of propargyl and allylic compounds in the presence of double bonds without hydrogenolysis, such as in 2 an intermediate in the total synthesis of the sesquiterpene sesquicarene ... 

To date more than 100 species from the large genus Baccharis have been investigated chemically. The most widespread compounds are clerodane diterpene derivatives, but labdane derivatives have also been isolated. Furthermore, typical acetylenic compounds, baccharis oxide, a unique triterpene, and derivatives of hydroxyacetophenone are present, although it is mainly other biologically active constituents, e.g. flavonoids, sesquiterpenes and essential oils that have been reported in the last years. The constituents of Baccharis species compiled from different sources are presented below. 

Cardui benedicti herba Cnici herba Blessed thistle Cnicus beiiedictus L. Asteraceae DAC 86. GAB 90, MD Sesquiterpene lactons (-0.25%), (germacran type) cnicin, salonitenolid and artemisiifoliii lit of the drug, 800-1800 Essential oil (0.03%-0.1%) citral, cilronellal cinnamic acid, acetylene derivatives Pig. 8... 

Paniculide-A is structurally the least complicated of the paniculides, a family of highly oxygenated sesquiterpenes from Andrographis paniculata. Jacobi s synthesis of paniculide-A began with a four-step conversion of 3-methyl glutaric anhydride 175 to the oxazole acetylenic ketone 176 (Fig. 3.54). Cycloaddition of... 

The third group of acetylenic compounds is not related clearly to the first two. Acetylenic linkages are occasionally introduced into compounds of diverse biosynthetic origin such as sesquiterpenes, tetraterpenes, and amino acids (Fig. 3.12). These compounds are found in unrelated plant families, among them the Annonaceae, Cupressaceae, Euphor-biaceae, Fabaceae, Lauraceae, Myoporaceae, Sapindaceae, Simaroubaceae, Sterculiaceae, Valerianaceae, and certain algae and mosses. 

Zhu Y, Zhang LX, Zhao Y, Huang GD (2010) Unusual sesquiterpene lactones with a new carbon skeleton and new acetylenes from Ajaniaprzewalskii. Food Chem 118 228... 

The coupling reaction of organocopper (LXXVI) and the iodoacetylene (LXXVn) is a key step in the total synthesis of the acetylenic sesquiterpene, freelingyne (LXXVni) (Knight and Pattenden, 1974). 

Bloch CB, De Wit PJGM, Kuc J (1984) EUdtation of phytoalexins by arachidonic and eicosapen-taenoic acids a host survey. Physiol Plant Pathol 25 199-208 Bohlmann F, Zdero C (1978) New sesquiterpenes and acetylenes from Athanasia and Pentzia species. Phytochemistry 17 1595-1599... 

An acetylenic 4-ylidenebutenolide of a quite different constitution is freelingyne (33). This highly unsaturated furano-sesquiterpene is found in the heartwood of the Australian shrub Eremophila freelingii, and it was the first acetylenic terpenoid to be isolated (55). Dihydrofreelingyne (34) has also been isolated from E. freelingii (36) and the unusual diterpenoid eremolactone (35) occurs in the leaves of the same species (37). The complete stereochemistry of freelingyne has been established by direct X-ray methods (38). 

Knight, D. W., and G. Pattenden Total Synthesis of the Acetylenic Sesquiterpene Freelingyne. Chem. Commun. 188, (1974). 

Synthesis of Freelingyne, an Acetylenic Sesquiterpene from Eremophila freelingii. 

The capnellenols, e.g. (24) [cf. (10)], are a unique family of sesquiterpenes, found in the soft coral Capnella imbricata. They are related structurally to the hirsutane family of triquinane terpenes, e.g. (18), but with the three methyl groups distributed differently about the tricycle. A special feature of the capnellenols is the presence of an unusual Wj-allylic alcohol functionality associated with ring c. The 8-epimer of (24) has now been synthesized by a route (Scheme 3) in which this novel functionality is introduced by annulation to (23) via reductive cyclization of the keto-acetylene precursor (22), followed by treatment of the resulting allylic alcohol (23) with t-butyl hydroperoxide in the presence of catalytic selenium dioxide. ... 

Other sesquiterpenes whose synthesis are worthy of mention are hibiscone C (38) (also known as gmelofuran), which is found in the heartwood of Hibiscus elatuSy and herbertene (40), isolated from the liverwort Herberta adunca. The synthesis of hibiscone by Koft and Smith" can be commended for its novel use of intramolecular [2 4- 2] photocycloaddition of the acetylenic enone (36) to set up the intermediate (37), whereas Prater s synthesis of herbertene is interesting, to say the least, since it involves a one-step acid-catalysed rearrangement of the alcohol (39) ... 

More than 1200 diterpenes have been identified from approximately 550 Compositae taxa (Figure 1 [pp. 219-384], Tables 1-3 [pp. 7-218]). The annual output of such reports rose sharply during the past several years, a trend that was also reflected by other major lipophilic constituents of the Compositae acetylenes (63, 465), sesquiterpene lactones (266, 458), and benzofurans and chromenes (429). Unlike these other natural products, no review of the diterpene chemistry of the Compositae has been published. Given the bulk of data currently on hand, a review of this topic is clearly overdue. 

Figure 22. Representative structures of di-, and tri-, and sesquiterpenes, flavonoids, acetophenones, coumarins, and poly acetylenes reported from Baccharis (Astereae). The numbers assigned to the structures correspond to the numbers listed in Table 8.

Siliquariaspongia°, Theonella Macrolactones, atypical sterols, linear and cyclic peptides, cyclic depsipeptides, nitrogen-containing sesquiterpenes, pyridine derivatives, acetylenic derivatives, phosphorus derivatives analogues of calyculin, tetramic acid glycosides... 

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