Aerothionin synthesis

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). 

Yamamura and coworkers have used a thallium trifluoroacetate mediated oxidative cyclization in their synthesis of aerothionin and related products and also in the synthesis of bastadin-6, a 28-membered ring lactone. 

Adamantyl haUdes, reactions of 677 p-(l-Adamantyl)phenols, synthesis of 606, 607 Aerophobin-1, biosynthesis of 1315, 1316 Aeroplysinin-1, synthesis of 1327, 1328 Aerothionin, biosynthesis of 1315, 1316 Ageing, free-radical theory of 140, 141 Agent Orange 12... 

Ogamino T, Obata R, Nishiyama S (2006) Symmetric synthesis of aerothionin, a marine dimeric spiroisoxazoline natural product, employing optically active spiroisoxa-zoline derivative. Tetrahedron Lett 47 727... 

Nishiyama S, Yamamura S (1985) Total synthesis of (+/-)-aerothionin, (+/-)-homo-aerothionin, and (-i-)-aerophobin-l. Bull Chem Soc Jpn 58 3453... 

A rather different phenolic oxidation, that of the oxime (154) with thallium(III) trifluroacetate to give the isoxazole (155), followed by zinc borohydride reduction, has been used to give (156) which is a versatile intermediate for the synthesis of the sponge metabolites ( )-aerothionin (157a), ( )-homoaerothionin (157b), and ( )-aerophobin-1 (158). ... 

Nishiyama, S. and Yamamura, S. (1983) Total synthesis of ( )-aerothionin and ( )-homo-aerofhionin. Tetrahedron Lett., 24, 3351-3352. 

Quite surprisingly, the first attempt to demonstrate the conversion of tyrosine into bromotyrosine derivatives was unsuccessful (175). In that experiment, Verongia aerophoba failed to incorporate radioactivity from U- " C -L-tyrosine into aerothionin (68), aeroplysinin-1 (14) and the dienone 1. Inactive aerothionin (68) was also isolated when the sponge was fed with U- C -L-ornithine and CH3- C methionine. However, the sponge utihzed these amino acids for the synthesis of fatty acids. A very slow rate of biosynthesis might account for these results. 

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