Plakohypaphorines

Campagnuolo C, Fattorusso E, Taglialatela-Scafati O (2003) Plakohypaphorines A-C, Iodine-Containing Alkaloids from the Caribbean Sponge Plakortis simplex. Eur J Org Chem 284... 

Scheme 32 Microwave-assisted selective dehalogenation of Plakohypaphorine F...

Another interesting application of microwave irradiation is found in the selective dehalogenation of the iodinated indole alkaloid Plakohypaphorine F, described by E. Fattorusso et al. [117,118] (Scheme 32). The bis-halogenated compound was treated with potassium formate and palladium acetate under controlled microwave irradiation, resulting in selective deiodination. The choice of the solvent, in this case DMSO, was found to be crucial. 

Plakohypaphorins A-F are the first iodinated indolic derivatives from homosclerophorid sponges. They are betaines derived from tryptophan that have been isolated from Plakortis simplex harvested in the Caribbean (Campagnuolo, Fattorusso, and Tagliatela-Scafati, 2003a Borrelli et al., 2004). The antihistaminic activity of these derivatives seems to be related to the number of atoms of iodine, with diiodine derivatives being the most active. 

Borrelli, F., Campagnuolo, C., Capasso, R., Fattomsso, E., and Taglialatella-Scafati, O. (2004) lodinated indole alkaloids from Plakortis simplex new plakohypaphorines and an evaluation of their antihistamine activity. Eur. J. Org. Chem., 3227-3232. 

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