Palinurin

Four unstable sulfate esters (373-376) of known furanosesterterpenes were obtained from Ircinia variabilis and from /. or os from the northern Adriatic Sea [328], The 22-O-sulfates of palinurin (377) and fasiculatin (378) were isolated from 7. variabilis and from /. fasiculata respectively. Both were toxic to brine shrimp [329]. Ircinianin sulfate (379) was isolated from /. (Psammocinia) wistarii from the Great Barrier Reef as a very unstable metabolite [330]. 

Palinurin. Hamann and co-workers reported the results of an interesting biocatalytic transformation of the furan ring to the corresponding amide in the bioactive marine natural product palinurin (46, X=0). The authors utilized long-range data to... 

Less common are those examples of this class of compound in which the tetronic acid moiety is nonconjugated. Palinurin (10a) was the first example of this class of compound, isolated from I. variabilis [37]. Subsequently, from an Australian Ircinia sp. was isolated a hydro derivative (11) of palinurin, which inhibits the growth of B. subtilis [38]. 

Palinurin (10b) and fasciculatin (16b) sulphates, together with the previously described palinurin (10a) and fasciculatin (16a), were isolated from the Tyrrhenian sponges I. variabilis and I. fasciculata, respectively. Yet again the sulphated derivatives were more active in A. salina bioassay (LC50 10b 3.04,16b 1.44,10a 7.56,16a 2.03 pg/ml) and less toxic in the fish lethality test (LC50 10b 2.30, 16b 2.20, 10a 1.67, 16a 1.04 pg/ml) [42]. 

Several compounds closely related to palinurin and spongionellin have been isolated [5,6] that showed moderate antimicrobial and cytotoxic activities. 

Palinurin (176), a linear furanosesterpene isolated from Ircinia sponges with antiinflammatory and antibacterial properties [100], has been synthesized in 2009 by Fall s group [101], The key step for the construction of the chiral tetronic acid moiety relies on the use of chiral pyrrolidine 174 (Scheme 1.27). 

Perez, M., Perez, D.L, Martinez, A, Castro, A., Gomez, G and Fall, Y. (2009) The first enantioselective synthesis of palinurin. Chem. Common., 3252-3254. 

De Rosa, S., De Giubo, A., Crispino, A., lodice, C., and Tommonaro, G. (1997) Palinurin and fasdculatin sulfates from two Thyrrenean sponges of the genus Ircinia. Nat. Prod. Lett., 10, 7-12. 

Al ito, G., Cimino, G., and De Stefano, S. (1979) Palinurin a linear sesterterpene from the sponge Ircinia variabUis. Experientia, 35, 1136-1137. 

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