Furodysin

Two thioacetates, thiofurodysin acetate (320) and thiofurodysinin acetate (209) were isolated from a Dysidea species from Sydney, Australia. They were converted by treatment with Raney nickel to a mixture containing furodysin and furodysinin respectively [214], These were the first thiol acetates isolated from natural sources. The absolute configurations of (-)-(6/ ,ll/ )-thiofurodysinin acetate (209), (-)-(6/ ,ll/ )-furodysinin disulfide (208) and (+)-(6/ ,ll/ )-methoxythiofurodysinin acetate lactone (321), isolated from a Fijian specimen of D. herbacea were determined by chemical interconversion [292]. 

An important variation of the theme is found in furans with a 3-substituent adjacent to the 2-substituent, for then elimination can give heteroquinone methides , possibly by cyclic mechanisms (71CCC4082). A common type is found in the breakdown of furodysin as illustrated in Scheme 8b (78TL4951), and which is probably reversed Diels-Alder in mechanism it often fails if the carbocyclic ring is seven-membered (75TL1421). 

C- H coupling constants, 4, 569 crystal data, 3, 623 mass spectra, 3, 610 structure, 4, 541 Furo[ 1,2]diazepines synthesis, 7, 598 Furo[ 1,3]diaze pines synthesis, 7, 607 Furodysin... 

Carte B, Keman MR, Barrabee EB, Faulkner DJ, Matsumoto GK, Clardy J (1986) Metabolites of the Nudibranch Chromodoris tunerea and the Singlet Oxygen Oxidation Products of Furodysin and Furodysinin. J Org Chem 51 3528... 

Several additional examples of the intramolecular cycloaddition of unactivated acetylenes with isomiinchnones were reported by Maier [30]. This cycloaddition approach represents an efficient method for providing rapid access to annulated furans present in several sesqui- and diterpenes, such as the panicu-lides [51],furanonaphthoquinones [52],furodysin,andfurodysinin [53,54].The decomposition of acyclic acetylenic diazoimides 102 and 103 with Rh2(OAc)4 resulted in cycloaddition and retro-Diels-Alder extrusion of methyl isocyanate to give annulated furans 104 and 105 in good yield. The overall transformation is closely related to the intramolecular Diels-Alder reactions of acetylenic oxa-zoles extensively studied by Jacobi and coworkers [55]. 

However, when the animals were stored in acetone for four weeks, the acetone extract gave furodysinin [47], furodysin [4 8], furodysinin lactone [4 9] and epoxylactone [50]. Isolation of the artifacts 47 - SO illustrates the effect of storage and solvent (acetone) on chemical stmctures of nudibranch s metabolites. 

Marine sponges of the genus Dysidea are a rich source of structurally unique and biologically active compounds, including spiro-sesquiterpenes such as spirodysin and dehydroherbadysinolide, furanosesquiterpenes based on the furodysinin and furodysin skeletons, brominated diphenyl ethers, polychlorinated alkaloids and other compounds [99-103],... 

Fig. (26). Spirodysins, furodysin and furodysinin isolated from Desidea herbacia.

Goetz, G.H., Harrigan, G.G., and Likos, J. (2001) Furodysin lactone and pyrodysinoic acid, new sesquiterpenes from a Philippine Dysidea species. J. Nat. Prod., 64, 1486-1488. 

Hirota, H., Kitano, M., Komatsubara, K, and Takahashi, T. (1987) Total synthesis of ( )-furodysin and ( )-furodysinin. Chem, Lett, 2079-2080. 

Vaillancourt, V, Agharahimi, M.R., Sundram, U.N., Richou, 0 Faulkner, D.J., and Albizati, K.F. (1991) Synthesis and absolute configuration of the antiparasitic furanosesquiterpenes (-)-furodysin and (—)-furodysinin. Camphor as a six-membered ring chiral template. J. Org. Chem., 56, 378-387. 

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