文摘
The isolation and structural determination of new marine ladder-frame polyethers, brevisulcatic acids-1 (1) and -4 (2) are reported. Brevisulcatic acids were isolated from the dinoflagellate Karenia brevisulcata, which was identified as the causative species of a major red tide event in New Zealand in 1998. The ether ring composition and a 尾-hydroxy, 纬-methylene valeric acid side chain of 1 and 2 are common, but 2 has a 纬-lactone as the 5-membered A-ring while 1 is the seco acid analogue. Compound 2 has structural and bioactivity similarities to brevetoxin A.