Calafianin

Naturally occurring dimeric spiroisoxazolines (+)-aerothionin (52) and (+)-calafianin (53) have been synthesized in enantiopure form and their configuration unambiguously assigned <06TL727 06OL927>. 

The synthesis of the spiroisoxazoline natural product (+ )-calafianin 447 has been reported, using asymmetric nucleophilic epoxidation and nitrile oxide cycloaddition as key steps. Syntheses and spectral analyses of all calafianin stereoisomers lead to unambiguous assignments of relative and absolute stereochemistry (494). 

The Mexican sponge Aplysina gerardogreeni contains calafianin (2106) (1880) (structure revised and confirmed by total synthesis, (1881-1883)), the known aerothionin, and the new phenylacetic acid 2107 (1880). These studies confirm that calafianin (2106) and aerothionin have the same absolute configuration (1883). Whereas aerothionin displays antibacterial activity against Mycobacterium tuberculosis, calafianin does not (1884). The Brazilian sponge Aplysina caissara contains the new caissarines A (2108) and B (2109) (1885). 

Encamacion RD, Sandoval E, Malmstr0m J, Christophersen C (2000) Calafianin, a Bromotyrosine Derivative from the Marine Sponge Aplysina gerardogreeni. J Nat Prod 63 874... 

Ogamino T, Nishiyama S (2005) Synthesis and Structure Revision of Calafianin, a Member of the Spiroisoxazole Family Isolated from the Marine Sponge, Aplysina gerardogreeni. Tetrahedron Lett 46 1083... 

Ogamino T, Obata R, Tomoda H, Nishiyama S (2006) Total Synthesis, Structure Revision, and Biological Evaluation of Calafianin, a Marine Spiroisoxazoline from the Sponge, Aplysina gerardogreeni. Bull Chem Soc Jpn 79 134... 

Bardhan S, Schmitt DC, Porco Jr. JA (2006) Total Synthesis and Stereochemical Assignment of the Spiroisoxazoline Natural Product (+)-Calafianin. Org Lett 8 927... 

A synthesis and structural revision of calafianin 49, a spiroisoxazoline isolated from the sponge Aphysina gerardogreene, was described. In particular, a trawi-relationship between the epoxy and isoxazoline oxygen atoms was established <05TL1083>. 

C. (2000) Calafianin, a bromotyrosine derivative from the marine sponge Aplysinagerardt reeni. J. Nat. Prod., 63, 874-875. 

Ogamino, T. and Nishiyama, S. (2005) Synthesis and structural revision of calafianin, a member of the sprroisoxazole family isolated from the marine sponge, Aplysina gerardogreeni. Tetrahedron Lett., 46, 1083-1086. 

Bardhan, S., Schmitt, D.C., and Porco, J.A. (2006) Total synthesis and stereochemical assignment of the spiroisoxazoline natural product (+)-calafianin. Org. Lett., 8, 927-930. 

Ogamino, T., Obata, R., Tomoda, H., and Nishiyama, S. (2006) Total synthesis, structural revision, and biological evaluation of calafianin, a marine spiroisoxazoline from the sponge, Aplysina gerardogreeni. Bull. Chem. Soc. Japan, 79,134—139. 

Calafianin (78), isolated from the Mexican sponge Aplysina gerardogreeni, is the only bromotyrosine derivative containing an epoxy group (30). 

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