Nakafurans

The other two Dvsldea metabolites tested, 5-acetoxy- and 5-hydroxy-nakafuran-8, 7 and 8, exhibited a different activity profile against the grasshopper. The acetate 7 was toxic at the high dose and antifeedant at the lesser dose, while the alcohol 8 was antifeedant at both doses. Surprisingly, the acetate 7 exhibited no activity in the tobacco hornworm assay. 

Sponges produce furanosesquiterpenes of various skeletal types, such as furodysinin (118) from Dysidea herbacea and nakafuran-8 (119) from D. etheria, the latter of which is antifeeding. Similarly, mixed shikrmate-mevalonate metabolites are often encountered as sponge metabolites the first example is avarol (120), which was isolated from Dysidea avara. Several related compounds have been isolated from dictyoceratid... 

Trimethylsilyl)diazomethane was also applied successfully to the total synthesis of pinguisane-type sesquiterpenes for the ring expansion (9-12) of the bicycloocte-none 9.16 by Uyehara et al. (1986). The same authors used (trimethylsilyl)diazome-thane for the ring expansion of the bicyclic ketone 9.17 (9-13) in studies on the synthesis of the novel sesquiterpenoid ( ) nakafuran-8, a bicyclo[4.2.2]decadiene with antifeedant properties (Uyehara et al., 1992). 

Cardellina, J.H. II and Bamekow, D.E. (1988) Oxidized nakafuran 8, sesquiterpenes from the sponge Dysidea etheria. Structure, stereochemistry and biological activity. J. Org. Chem., 53, 882-884. 

Tanis, S.P. and Herrinton, P.M. (1985) Furans in synthesis. 5. Furan-terminated cationic cydizations in the preparation of fused, spirocydic and bridged ring systems. An application to the synthesis of nakafuran 9. J. Org. Chem., 5, 3988-3996. 

Uyehara, T, Sugimoto, M., Suzuki, L, and Yamamoto, Y. (1989) Total synthesis of ( )-nakafuran-8, marine metabolite with antifeedant properties based on formal bridgehead substitution of a bicyclo[2 2 2J oct-5-en-2-one system. J. Chem. Soc. Chem. Commun., 1841-1842. 

Chromodorls maridadllus Nakafurans 8 and 9 Dysidea fragilis Schulte, Scheuer, and McConnell, 1980... 

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