Laurencia perforata

Perforatone (46) and perforenones A (47 R = OH) and B (47 R = Cl) have been discovered in the marine alga Laurencia perforata.78 It is suggested that (46) and (47) are formed from a chamigrene cation (48), and this hypothesis provides a full rationale for the biosynthesis of the wide variety of sesquiterpenoids that have been isolated from Laurencia species. 

Further investigation of the seaweed species Laurencia perforata has revealed the presence of two new metabolites, perforenone (185) and perforenone-C (183) (c/. Vol. 6, p. 65 Vol. 7, p. 70). These compounds are further examples of a comparatively new structural type of sesquiterpenoid whose carbon skeleton is presumably derived by rearrangement of a chamigrene precursor (c/. Vol. 6, p. 65 Vol. 7 p. 70). Structures (183) and (185) were established by chemical correlation with perforatone (182), a previously reported constituent of L. perforata, and by the synthetic sequence outlined in Scheme 16. 

The structure of the photo-product of d(TpT) (11) in aqueous solution has been established by 220 MHz n.m.r. spectroscopy. The spectrum is consistent with the structure (11) having a cis-syn-cyclobutane ring. A new sesquiterpenoid containing a cyclobutane ring has been isolated from the algae Laurencia perforata. The structure of the compound, perforatone (12), was elucidated by chemical transformation and by the use of the lanthanide shift reagent [Eu(fod)3] to simplify the n.m.r. spectrum of the corresponding alcohol. 

An unusual sesquiterpene with a rearranged tenerane" carbon skeleton was identified in an Australian Laurencia perforata along with perforane derivatives (Wright, GocHk, and Konig, 2003). 

Aplysia kurodai Yamamura and Terada, 1977 Laurencia perforata Gonzalez et ai., 1985b... 

Gonzalez, A.G., Aguiar, J.M., Martin, J.D., and Norte, M. (1975b) Three new sesquiterpenoids from the marine alga Laurencia perforata. Tetrahedron Lett., 16, 2499-2502. 

The food chain between the Japanese species Aplysia kurodai and Laurencia concinna (Ceramiales) and Laurencia perforata yielded three closely related brominated diter-penes aplysin-20 was found only in the sea hare (Matsuda et al, 1967) isoaplysin-20 was identified in the mollusk and in Laurencia perforata and concinndiol was isolated only from Laurencia concinna. These three structures and their biosynthetic patterns are presented in Chapter 13. More recently, the food chain between the species Aplysia parvula and the red alga Laurencia filiformis, harvested in Tasmania, has led to similar comments (Jongaramruong et al, 2002). Other examples of brominated diterpenes found in Aplysia and Laurencia are presented in Chapter 13 (see also Komprobst and Al Easa, 2003). 

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