Novel pteridine alkaloids from the sponge Clathria sp.

Three novel pteridine alkaloids, pseudoanchynazines A–C () have been isolated from the sponge Clathria sp. collected by trawling (−100 m) in a commercial clam fishery near the coasts of Rio Negro, Argentina, and their structures determined by a combination of chemical and spectroscopic techniques, with emphasis in 2D NMR and tandem mass spectrometry. Compounds have two pteridine units and a tryptophan core with a methyl carbamate substituent.