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.