5 NEW ALKALOIDS FROM THE TROPICAL ASCIDIAN, LISSOCLINUM SP - LISSOCLINOTOXIN-A IS CHIRAL

Five new alkaloids, lissoclin A (1), lissoclin B (2), Lissoclin C (3), lissoclinotoxin C (5), and the dimeric lissoclinotoxin D (6), were is olated along with the known compounds lissoclinotoxin A (4), 2-phenyle thylamine (11), and 6-bromotryptamine (12) from Lissoclinum sp. collec ted from the Great Barrier Reef, Australia. Lissoclin A (1) undergoes photorearrangement to a new benzo-l,and oxathiazoline 10. The C-13 NMR spectrum of 4 is reported for the first time and the structure indepe ndently assigned by conversion to the known varacin N-trinuoroacetamid e with diazomethane and [C-13]diazomethane. Compound 4 is chiral and e xhibits unusual stereoisomerism due to restricted inversion about the benzopentathiepin ring. Lissoclinotoxin A (4) and D (6) exhibit antifu ngal activity against Candida albicans.