Tropical Marine Algae. I. New Halogenated Monoterpenes From Chondrococcus hornemannii (Rhodophyta, Gigartinales, Rhizophyllidaceae)

Abstract

Four linear halogenated monoterpenes: (2Z,6E)-1,8-dichloro-3-chloromethyl-7-methylocta- 2,6-diene (1), (E)-1,2-dibromo-3-chloromethylene-7-methyloct-6-ene (2), (Z)-1-chloro-3-chloromethyl-7-methylocta-2,6-diene (3) and (Z)-1,6-dichloro-3-chloromethyl-7-methylocta-2,7- diene (4), and two epimeric bicyclic monoterpenes (2R*,3(8) E,4S*,6R*)-6-bromo-2-chloro-1,4- oxido-3(8)- ochtodene (5) and (2S*,3(8)E,4S*,6R*)-6-bromo-2-chloro-1,4-oxido-3(8)- ochtodene (6) have been isolated from the red alga Chondrococcus hornernannii collected on the Great Barrier Reef, Australia. The structures were assigned on the basis of 1H and 13C n.m.r. spectroscopic studies, and provide another example of the co-occurrence of cyclized and linear halogenated monoterpenes in the same species.