NOVEL MARINE SPONGE DERIVED AMINO-ACIDS .13. ADDITIONAL PSAMMAPLIN DERIVATIVES FROM PSAMMAPLYSILLA-PURPUREA

An investigation of a sponge rich in psammaplin derivatives provides some insight into the biogenesis of this group of amino acid derivatives. Accompanying psammaplin A (1) were a new cysteine dimer, prepsammaplin A (2), and three new bromotyrosine-cysteine derivatives, psammaplins B (3), C (4), and D (5). Two other compounds were isolated including (3-bromo-4-hydroxy) benzaldehyde (6) and (3-bromo-4-hydroxyphenyl)-acetonitrile (7) which appear to be bromotyrosine derivatives. Psammaplin D (5) showed antimicrobial and mild tyrosine kinase inhibition activity.