6,12-Germacranolides

Kanasaki and Ohta 172) reported the isolation of (406) from Marchantia polymorpha. From the chemosystematic point of view, the female, the male and sterile thalii of M. polymorpha were reinvestigated however, neither costunolide (406) nor related germacranolides were isolated or detected in any of these sources (25). M. polymorpha is often 

The germacranolides isolated from the Hepaticae have the same 6a,7p-configuration as those found in the higher plants although the Hepaticae generally elaborate sesquiterpenoids antipodal to those found in higher plants. 

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The intramolecular Hiyama reaction is excellently suited for the construction of carbocyclic and heterocyclic ring systems of different size. In most examples, problems of induced diastereoselectivity are involved (Sections 1.3.3.3.9.2.2. and D.2.3.). In the total synthesis of the antitumor germacranolide ( )-costunolide from ( ,.E)-farnesol, the correctly substituted ( , )-cyclodecadiene moiety was constructed by an intramolecular Hiyama reaction22. 

A. artemlsllfolla (8), we had isolated the germacranolide 11,13-dihydroparthenolide (16) the germination activity effects of which will be discussed in the following section together with the other sesquiterpene lactones. 

Elephantopus mollis is interesting because it elaborates a series of cytotoxic antitumor germacranolides including molephantinin and phantomolin, which are cytotoxic in vitro and in vivo against Ehrlich ascites carcinoma and Walker 256 carcinosarcoma in rodents (104,105). Molephantinin mitigates DNA and protein synthesis in Ehrlich ascites carcinoma cells and DNA synthesis. What is the activity of molephantinin on apoptosis (106)1... 

Lee KH, Ibuka T, Furukawa H, Kozuka M, Wu RY, Hall IH, Huang HC. Antitumor agents XXXVIII Isolation and structural elucidation of novel germacranolides and triterpenes from Elephantopus mollis. J Pharm Sci 1980 69 1050-1056. 

The cyclobutanone (201) also underwent smooth oxidation to afford the y-lactone (202), which was not isolated and was allowed to react further to yield the cytotoxic germacranolide eucannabinolide (203) in a number of steps 70 (... 

This ring contraction has been used to provide the ten-membered ring of the germacranolide aristolactone (4) from a 13-membered allylic propargylic ether. 

In 1959-61, a Czech group [8,9] reported the isolation of a new sesquiterpene lactone from Chrysanthemum (Tanacetum) parthenium as part of a study of the sesquiterpene lactones of the Compositae family. They named it parthenolide. The initial structure for parthenolide was later revised [10,11] and the accepted structure for parthenolide today is represented by structure (1). Parthenolide is a germacranolide-type sesquiterpene lactone. The crystal structure for parthenolide has also been reported [12]. Extractions of C. (T.) parthenium grown in Mexico, known locally as santamaria, did not yield parthenolide [13], but a closely related compound was isolated and named santamarine (3). This suggests that regional variations in the chemical constituents may occur. 

In summary, feverfew appears to be a source of a range of sesquiterpene lactones of three different types germacranolides, eudesmanolides and guaianolides. 

The diverse biological activity (allergenic, antitumour, fungitoxic, phytotoxic, cytotoxic, etc.) of germacranolides (226a and b) and other sesquiterpenoids containing cx/S-unsaturated y-butyrolactone units has been reviewed. During the period of... 

A new approach to the cyclodeca-1,5-diene systems [cf. (281) and (282)] characteristic of germacranolides involves a photochemical-cycloaddition and thermal-cycloreversion sequence shown in Scheme 27. ... 

A few individual terpenoids, as well as less expensive mixtures of these compounds, find practical applications. Some examples are the tli terpenoid Vitamin A, the sesquiterpenoid santonin (as an anthelmintic), and the pyrcthnns, pyrctholonc esters of the monoterpenoid chrysanthcmic acid (used as an insecticide). A number of sesquiterpenoid lactones of the germacranolide. guaianolide and elemanolide types have shown promise as rumor inhibitors. 

The plant Achillea clusiana from the mountains of Bulgaria contains the new 2-epi-chIoroklotzchin (256), which is the first report of a halogenated sesquiterpene lactone from Achillea genus (512). Chloroform was used to process the plant. The Egyptian medicinal plant Ambrosia maritima, which is still used to treat renal colic and other aliments, has afforded 1 lp-hydroxy-13-chloro-l 1,13-dihydrohymenin (257) (513). Eupaglehnins E (258) and F (259) are novel germacranolides isolated... 

Tori M, Takeichi Y, Kuga H, Nakashima K, Sono M (2000) Two New Chlorine-Containing Germacranolides, Eupaglehnins E and F from Eupatorium glehni. Heterocycles 52 1075... 

Caruifolin A (germacranolide sesquiterpene) Artemisia caruifolia (Asteraceae) HIV-1 protease (< 50% inhibition at 376 pM) [51]... 

B. gaudichaudiana, which is commonly used for diabetes. Elephantopus scaber contains hydroxylated germacranolides, such as molephantin and molephantinin, which cause diuresis, antipiresis, eliminate bladder stones, and have cytotoxic and antitumor properties. From the Tithonia genus, T, diversifolia is widely used in Mexico and often has been identified erroneously as Arnica montana. Because of this confusion it is used as European arnica to treat hematomas and muscular cramps. The genus is rich in sesquiterpene lactones.11... 

The structures of peucephyllin (172)80 (Peucephyllum Schottii Gray) and the related cytotoxic germacranolide eupaformonin (173)81 (c/. p. 93) (Eupatorium formosum... 

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