Pinna muricata, pinnaic acid

Three novel related marine alkaloids, halichlorine (1148) from the sponge Halichondria okadai (1177, 1178) and pinnaic acid (1149) and tauropinnaic acid (1150) from the bivalve Pinna muricata (1179), have been the objects of much synthetic interest in view of their pronounced biological activity (inhibition of the vascular cell adhesion molecule-1) (1180). Synthesis of these alkaloids led to both revision and confirmation of the original structures (1181,1182). The syntheses of the previously known chlorine-containing cylindricines have been reviewed (1183). 

Chou T, Kuramoto M, Otani Y, Shikano M, Yazawa K, Uemura D (1996) Pinnaic Acid and Tauropinnaic Acid Two Novel Fatty Acids Composing a 6-Azaspiro[4.5]decane Unit from the Okinawan Bivalve Pinna muricata. Tetrahedron Lett 37 3871... 

Tong, C., Kuramoto, M., Otani, Y, Shikano, M., Yazawa, K. and Uemura, D, 1996. Pinnaic acid and tauropinnaic acid two novel fatty acids composing a 6-azaspiro[4.5]decane unit from the Okinawan bivalve Pinna muricata.. Tetrahedron Lett 37, 3871-3874. 

The same research group also explored a transannular nitrone-olefin [3 + 2] dipolar cycloaddition approach to the spirocyclic core of pinnaic acid, an inhibitor of phospholipase A2 (CPLA2) that was isolated from the Okinawan bivalve Pinna muricata The nitrone 34 was prepared by acidic hydrolysis of the ethylene ketal and the oxaziridine of 32 to generate transiently the keto... 

Pinna muricata has also yielded the two original acids pinnaic add and tauropinnaic add, which have the same 6-azaspiro-[4,5]-decane system. These two derivatives... 

---