Ceratinadins A-C, new bromotyrosine alkaloids from an Okinawan marine sponge Pseudoceratina sp.

Three new bromotyrosine alkaloids, ceratinadins A-C (1-3), were isolated from an Okinawan marine sponge Pseudoceratina sp. and the structures of 1-3 were elucidated on the basis of spectroscopic data. Ceratinadin A (1) was a novel bromotyrosine alkaloid possessing an N-imidazolyl-quinolinone moiety.