Plocamium Halogen compounds

One of the more thoroughly studied rhodophyte genera is Plocamium (Plocamiaceae), from which highly halogenated cyclic and acyclic compounds have been... 

New cyclic halogen-containing monoterpenoids include plocamene C (74)" (c/. Vol. 6, p. 33). No structural details were available in the abstract. This compound is closely related to violacene 2 (75) which was isolated from Plocamium violaceum the structure, determined by X-ray analysis, was inadvertently omitted from last year s Report." Chondrococcus hornemanni has also yielded chondrocole C (76), and the related tentative structure (77) has been assigned to a second component." ... 

One of the metabolites isolated from the red alga Plocamium costatum is a halogenated cyclized norgeraniolene, costatolide (170), ° and this has been synthesized. It has also been converted to the Cxo-compound costatone (171), isolated from the same alga, ° and placed here instead of in the pyran section because of the relationship with costatolide. In a synthesis of the latter, the (Z)-orientation of the vinyl chloride group could not be assured by chlorination... 

DDT (trace A) and its metabolites DDE and DDD (trace B), and traces F and G are the commercial polychlorinated biphenyl (PCB) mixtures Arochlor 1242 (trace F) and Arochlor 1254 (trace G). As is illustrated, extracts of local Laurencia species (traces C and D), and the extract of a halogenating bacterium Chromobacterium sp. (trace E), contain compounds of similar retention time to DDT and its metabolites. Traces H and J were produced from extracts of Plocamium cartilagineum and Chondria californica, two locally abundant red algae, and trace I was produced from a species unidentified sponge of the genus Verongia. In this case mixtures of halogenated natural compounds fall within the limits of detectability of the PCBs. 

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