TWO NEW ISOMERS OF DOMOIC ACID FROM A RED ALGA, CHONDRIA ARMATA

摘要

Isodomoic acids G and H, two new isomers of the neurotoxin domoic acid, along with isodomoic acids A, B, E and F, were isolated from a red alga, Chondria in armata, collected at the southern tip of Kyushu Island. The structures of two of these were deduced to be (E, E) and (Z, E) isomers of 2-carboxy-4-(5-carboxy-1-methyl-2-hexenylidene)-3-pyrrolidineacetic acid, based on electrospray ionization mass and [H-1]nuclear magnetic resonance spectral analyses including [H-1-H-1]correlation spectroscopy and nuclear Overhauser effect correlation spectroscopy. (C) 1997 Elsevier Science Ltd. [References: 10]