Isolation and Synthesis of 4-Bromopyrrole-2-carboxyarginine and 4-Bromopyrrole-2-carboxy-N(ε)-lysine from the Marine Sponge Stylissa caribica

Two new bromopyrrole alkaloids were isolated from the Caribbean sponge Stylissa caribica. The new natural products, 4-bromopyrrole-2-carboxyarginine (1) and 4-bromopyrrole-2-carboxy-N(epsilon)-lysine (2), are derivatives of amino acids linked with a 4-bromopyrrole-2-carboxylic acid. The structures were elucidated on the basis of NMR and MS/MS data and their absolute configurations assigned via synthesis.