New unusual alkaloids from the ascidian Eudistoma vannamei.

The MeOH extract of the ascidian Eudistoma vannamei was found to contain three novel compounds, the adenine alkaloid derivatives 9-[N-(leucyl)-isoleucyl]- adenine (1) and 8-hydroxy-8-isopentyl-7,8-dihydroadenine (2), and the phenylalanine peptide derivative N-[N-(leucyl)-isoleucyl]phenethylamine (3). Other previously related compounds isolated from this extract include thymidine, 2'-deoxyuridine and phenylalanine. The structures of the new compounds were elucidated through the use of NMR and mass spectrometry.