Sesterterpenes structure

A Californian sponge of the Halichondriidae family contained a sulfated sesterterpene hydroquinone and five sulfated sesterterpenes. The structures of the halisulfates 1-5 (359-363) were determined by interpretation of spectral data and a structure was proposed for halisulfate 6 (364). The halisulfates are antimicrobial and antiinflammatory [318]. The absolute configuration of halisulfate 3 (361), which was also isolated from Ircinia sp. from the Philippines, has been determined by application of the chiral amide method and by chemical degradation techniques [319]. Halisulfate 7 (365) is a sesterterpene sulfate from a Coscinoderma sp. from Yap, Micronesia [320]. 

Sulfircin (369), an antifungal sesterterpene sulfate was isolated as the iV,iV-dimethylguanidinium salt from a deepwater Ircinia species and its structure was determined by X-ray analysis [324]. Two sesterterpene sulfates, hipposulfates A (370) and B (371), were isolated from Hippospongia cf. metachromia from Okinawa and their structures were elucidated by interpretation of spectroscopic data. Both compounds possess an enolsulfate functionality [325]. 

Renner MK, Jensen PR, Fenical W (1998) Neomangicols Structures and Absolute Stereochemistries of Unprecedented Halogenated Sesterterpenes from a Marine Fungus of the Genus Fusarium. J Org Chem 63 8346... 

The terpenoids form a large and structurally diverse family of natural products derived from C5 isoprene units (Figure 5.1) joined in a head-to-tail fashion. Typical structures contain carbon skeletons represented by (Cs) , and are classified as hemiterpenes (C5), monoterpenes (C10), sesquiterpenes (C15), diterpenes (C2o), sesterterpenes (C25), triterpenes (C30) and tetraterpenes (C40) (Figure 5.2). Higher polymers are encountered in materials such as rubber. Isoprene itself (Figure 5.1) had been characterized as a decomposition product from various natural cyclic hydrocarbons, and was suggested as the fundamental building block for these compounds, also referred to as isoprenoids . Isoprene is produced naturally but is not involved in the formation of... 

Hainan Is., China) contained 12o -0-acetylhyrtiolide (197) [103]. A new scalarane-type pentacyclic sesterterpene, sesterstatin 6 (198), was isolated from the Republic of Maldives marine sponge Hyrtios erecta. The structure was elucidated by analyses with HRMS and high-field 2-D NMR spec-... 

Schmitz and co-workers next published a pair of papers that dealt with the isolation and characterization of sesterterpenes from two different sponges. The first of these reports described the structural characterization of phyllofolactones C and D, minor homoscalarane sesterterpenes from the Chinese sponge Phyllospongia foliascens.117 The structure of phyllofolactone-C (54) is shown. The second report detailed the characterization of halisulfate-7 (55), a sesterterpene sulfate from a sponge, Coscinoderma sp.118... 

ABSTRACT Marine invertebrates such as ascidians, sponges and others are a prolific source of bioactive secondary metabolites. We have isolated a variety of marine natural products from the Okinawan marine invertebrates by using the sea urchin egg assay. Our recent work, the isolation, structure determination and activities of chlorinated macrolides, sesterterpenic acids, a bromotyrosine derivative, acetogenin derived endoperoxides, diterpene alkaloids, sesquiterpene quinones and spiro-sesquiterpenes, is presented in this article. The syntheses of these metabolites are also described. 

The structures of terpenes or terpenoids varies widely and are classified according to various aspects, e.g. number of isoprene units (Cio monoterpenes, C15 sesquiterpenes, C20 diterpenes, C25 sesterterpenes, C30 triterpenes, C40 tetraterpenes) or division in acyclic, mono-, hi-, tri-, tetra-, pentacyclic terpenes. Often terpenes are named by their trivial names, e.g. d-limonene. 

In the same year Tsuda et al. (27) reported the isolation of cytotoxic sesterterpenes from the Okinawan marine sponge Luffariella sp. among which was a compound with a 5,6-dihydro-a-pyrone moiety, luffariolide E. This compound showed cytotoxicity against murine leukaemia LI210 cells (IC50 1.1-7.8 pg/ml) in vitro. The original structure, which rested on chemical and spectroscopic evidence, has been corrected by synthesis to (24) (28). 

A second type of sesterterpenes including cheilanthatriol (107) has been isolated from the fern Cheilanthes farinosa. This compound appears similar in certain structural aspects to some triterpenes (Khan et al., 1971). 

Contents P. S. Steyn and R. Vleggaar Tremorgenic Mycotoxins. — R. E. Moore Structure of Palytoxin. — P. Crews and S. Naylor Sesterterpenes An Emerging Group of Metabolites from Marine and Terrestrial Organisms. 

Two types of secretion with a structural role, from scale insects and solitary bees, warrant inclusion here. The waxes of scales from the genus Ceroplastes contain unusual sesterterpenes new examples of constituents with known skeletons have been published,together with two new skeletal classes, floridenol (37), flocerol (38) and their derivatives. Three novel diterpenoids, including (39), have also been isolated from this source. 

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... 

---