Itampolins A and B, new brominated tyrosine derivatives from the sponge Iotrochota purpurea

Two new compounds, designated as itampolins A (1) and B (2) were isolated from the sponge Iotrochota purpurea collected at Itampolo, southwest of Tuléar, Madagascar. The structures of the compounds were elucidated mainly on the basis of 1D and 2D NMR and mass spectroscopic data and, in the case of 1, also by chemical degradation.