The cymopols, a group of prenylated bromohydroquinones from the green calcareous alga Cympolia barbata

Abstract

Seven new hydroquinones have been isolated from the green alga Cymopolia barbata. These are cymopol [2-bromo-5-(3,7-dimethylocta-2,6-dienyl)hydroquinone] and its monomethyl ether, cyclocymopol [1-bromo-3-(4-bromo-2,5-dihydroxybenzyl)-2,2-dimethyl-4-methylenecyclohexane] and its monomethyl ether, cymopolone [(4-bromo-2,5-dihydroxyphenyl)trans-(2,6-dimethylhepta-1,5-dienyl) ketone], and its cis-isomer, and cymopochromenol [7-bromo-6-hydroxy-2-methyl-2-(4-methylpent-3-enyl)-2H-1-benzopyran]. The structure and absolute stereochemistry of cyclocymopol monomethyl ether acetate were established by X-ray crystallography.