Marine sesquiterpenoid

The antipodal relationship appears secure despite differences in the magnitude of the rotation values ([a]D 32, —63° 43, +100°), both of which were measured in CC14. Of particular interest is the isothiocyanato-alcohol 46, which is the first example of an oxygenated marine sesquiterpenoid possessing a function unrelated to the -NC/-NCS/-NHCHO triad. 

This multicomponent reaction was used by the same group to prepare a ring-expanded analogue 114 of the marine sesquiterpenoid frondosin B through a remarkable reaction cascade [102]. An unprecedented tandem 1,7-hydrogen shift, 8 7r-electrocyclization converting 112 to 113 was proposed to explain the formation of this ring-expanded species (Scheme 8.47). 

Structural elucidation of the terpenoid constituents of marine plants and animals has revealed the presence of several compounds whose novel structures often have chlorine, bromine, or isocyanide substituents (cf. pp. 65 and 89). 9-Isocyano-pupukeanone (273) is a recent example of a marine sesquiterpenoid isolated from a... 

Further additions to the ever-increasing number of marine sesquiterpenoids of unusual structure are brasilenol (672) and epibrasilenol (673). These two compounds were isolated from the digestive glands of the sea hare Aplysia brasiliana. It has been established that they are also metabolites of the alga... 

This compound must arise from bromonium ion cyclization of the 6,7-bromohydrin of farnesol acetate. Hydrolysis of the acetate group in (47) and sequential treatment with phosphorus tribromide and water gave obtusenol (46). Other syntheses of marine sesquiterpenoids include those of pallescensin-E (48),30 furoventalene (49),81 and dactyloxene-B (50) and -C (51).32 The last mentioned established the absolute configurations of the two dactyloxenes. A second synthesis of ancistrofuran (53) and its C-2 epimer has been recorded starting from the lactone (52) which is derived from homogeranic acid (Scheme 3).33... 

Lucas, R., Giannini, C., D auria, M. V., and Paya, M. (2003). Modulatory effect of bolinaqui-none, a marine sesquiterpenoid, on acute and chronic inflammatory processes. /. Pharmacol. Exp. Ther. 304,1172-1180. 

Full details of the structural determination of nigakialcohol (24) have been published. Co-occurring with aplysistatin (25) in Laurencia cf. palisada Yamada are the marine sesquiterpenoids palisadin A (26) and B (27), 5-acetoxypalisadin B (28), 12-hydroxypalisadin B (29), and palisol (30). 3/3-Bromo-8-epi-caparrapi oxide (32) has been synthesized by a procedure which... 

A second synthesis of the marine sesquiterpenoid pallescensin A (49) has been achieved by acid-catalysed cyclization of the furanodiene (48). Continued... 

A synthesis of the unique marine sesquiterpenoid sinularene (212) has been achieved by a route which closely parallels the methodology used by Money et to synthesize copacamphor and ylangocamphor (Scheme 25). Full details of the very interesting synthesis of cyclosativene (215) have been published. As shown in Scheme 26, the critical synthetic step involves the solvolysis of the bicyclic tosylate (213) which proceeds by intramolecular capture of the cyclo-propylcarbinyl cation by the pendant acetylene group to afford (214). 

The group of Metz employed the proline-derived catalyst 159 in combinatiOTi with co-catalyst 160 to catalyze additions of (/ )- and (S )-citronellal (157) to 158 for the selective syntheses of the diastereomeric keto aldehydes 174 and 175. These intermediates could then be used to synthesize the marine sesquiterpenoids (—)-clavukerin A (176) (starting from (S )-157) and ( )-isoclavukerin A (177) (derived from (/ )-157) (Scheme 41) 162). 

Photochemical oxa-di-jt-methane rearrangement of bicyclo[3.2.1]octa-noid scaffolds affords multifunctional, donor-acceptor cyclopropanes (34). Application of this reaction to bicyclo[2.2.2]octenones has been used as a key step in the total synthesis the hirsutane-type sesquiterpenes (-)-connatusin A (35), (+)-connatusin B (36), and the marine sesquiterpenoid 2-isocyanoallopupukeanane (37). ... 

The Et2Zn-promoted umpolung methodology has been applied to the total synthesis of ( )-erythrodiene, a marine sesquiterpenoid (Scheme 23). Thus, the... 

Cao S, Gao Z, Thomas SJ, Hecht SM, Lazo JS, Kingston DG (2004) Marine sesquiterpenoids that inhibit the lyase activity of DNA polymerase p. J Nat Prod 67 1716 1718... 

Rosini, G., Laffi, E., Marotta, E., Pagani, I., and Righi, P. (1998) Total synthesis of the marine sesquiterpenoid raikovenal tiirough a novel utilization of the bicydo[3.2.0]heptenone approach. J. Org. Chem., 63, 2389-2391. 

Iwashima, M., Terada, 1., Igudii, K., and Yamori, T. (2002) New biologically active marine sesquiterpenoid and steroid from the Okinawan sponge of the genus Axinyssa. Chem. Pharm. Bull., 50, 1286-1289. 

Iguchi, K., Mori, K., Matsushima, M., and Yamada, Y. (1987b) Spirotubipolide, a new marine sesquiterpenoid from the stolonifer Tubipora musica Linnaeus. Chem. Pharm. Butt., 35, 3531-3533. 

Lewis, M.L. and de Meijere, A. (1997) Total synthesis of marine sesquiterpenoids containing a primnatriene skeleton. Synlett, 261-262. 

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