ARNOAMINE-A AND ARNOAMINE-B, NEW CYTOTOXIC PENTACYCLIC PYRIDOACRIDINEALKALOIDS FROM THE ASCIDIAN CYSTODYTES SP

Two new cytotoxic pyridoacridine alkaloids, arnoamines A (1) and B (2) , have been isolated from the ascidian Cystodytes sp. collected in the vicinity of Arno Atoll, Republic of Marshall Islands. Compounds 1 and 2 are proposed to be the first members of a new class of pentacyclic pyridoacridine alkaloids possessing a pyrrole ring fused to the pyrido acridine ring system. The structures of 1 and 2 were proposed on the b asis of the interpretation of spectroscopic data, particularly those o btained from HMBC and NOE NMR experiments. The arnoamines were unexpec tedly found to incorporate deuterium at C-10 and C-11 of the pyrrole r ing when dissolved in CDCl3/TFA-d.