Sesterterpenes scalaranes

These types of compounds also showed other interesting properties, such as antineoplasic and cytotoxic activity reported from scalarane-type sesterterpenes of the Indian Ocean sponge Hyrtios erecta [109,110], and antituberculosis properties [111]. 

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-... 

Meroterpenes are fotmd almost exclusively in the genus Dysidea and they involve either a sesquiterpene of the drimane series, a sesterterpene of the scalarane series, with an aromatic moiety that is most often a hydroquinone or quinone, sometimes substituted with a taurine (the melemeleones of Dysidea amra). There are, however, some atypical structures of the dimeric type, containing an aminoquinone. Figures 19.98-19.104 present some examples of terpenes and meroterpenes of dendroceratid sponges some of these have been found, with or without... 

Sesterterpenes are major derivatives in the Dictyoceratida, in which there are about 200 structures of class D and nearly 160 other stmctures that do not have a scalarane or 20,22-bishomoscalarane skeleton. The main carbon skeletons of these sesterterpenes are presented in Figure 19.118. 

Figure 19.119 (a) Sesterterpenes of the scalarane family isolated from dictyoceratid sponges (b) Further sesterterpenes of the scalarane family... 

Jaspars, M., Jackson, E., Lobkovsky, E., Clardy J., Diaz, M.C., and Crews, P. (1997) Using scalarane sesterterpenes to examine a sponge taxonomic anomaly. /. Nat. Prod., 60, 556-561. 

Jimenez, J.I., Yoshida, W.Y, Scheuer, P.J., and Kelly, M. (2000b) Scalarane-based sesterterpenes from an Indonesian sponge Strepsichordaia aliena. J. Nat. Prod., 63,1388-1392. 

Youssef D.T.A., Shaala, L.A., and Emara, S. (2005) Antimycobacterial scalarane-based sesterterpenes from the Red Sea sponge Hyrtios erecta. J. Nat. Prod., 68, 1782-1784. 

Yu, Z.-G., Bi, K.-S., and Guo, Y.-W. (2005) Hyrtiosins A-E, five new scalarane sesterterpenes from the South China sea sponge Hyrtios erecta. Helv. Chim. Acta. 88,1004-1009. 

Kuldtki, V., Ungur, N., Gavagnin, M., Castelluccio, F., and Cimino, G. (2007) Ring B functionalization of scalarane sesterterpenes by radical relay halogenation. Tetrahedron, 63, 7617-7623. 

Most sesterterpenes isolated from nudibranchs possess the carbon skeleton of scalarane and 20-homoscalarane (C26), many examples of which were given in the account of dictyoceratid sponges (see Figure 19.72), and for several... 

Inorolides A and B are original sesterterpenes which were isolated from the Japanese species Chromodoris inor-nata with a third derivative, inorohde C, which has the carbon skeleton of cheilanthane. A further study of the same species by the same team yielded new examples of scalarane derivatives, and a hypothesis relating the carbon skeletons of sesterterpenes isolated from dictyoceratid sponges to those from nudibranchs has been proposed (Figure 23.23) (Miyamoto et al., 1992, 1999). 

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