Search

Four new alicyclic monoterpenes based on the 1-(2-chlorovinyl)-2,4,5-trichloro-1,5-dimethylcyclohexane skeleton were isolated from Plocamium cartilagineum from the Chilean coast, together with four known cyclic monoterpenes. The structure of the new compounds were determined by comparison of the spectral data with those of known compounds. The insecticide/acaricide and fungicide activities of some of the isolated monoterpenes were determined.

Meroditerpenoids, 2-[2'(E)-3',7',11',15'-tetramethylhexadec-2-en-1'-yl]-6-methyl-1,4-benzohydroquinone diacetate and 4'-chlorostypotriol triacetate, along with eight known compounds isolated from the dichloromethane extract of the brown alga Stypopodium flabelliforme after peracetylation are reported. One of them, 2-(1-oxo-hexadecyl)-1,3,5-trihydroxybenzene, is described for the first time within this genus. Structural elucidation was carried out on the basis of spectroscopic data and theoretical studies using GIAO/DFT analysis at B3LYP/6-31G(d) and mPW1PW91/6-31G(d) levels of theory for 4'-chlorostypotriol. This isomer is the first metabolite from the Stypopodium genus possessing one halogen atom.

Pacifenol, a halogenated sesquiterpene was isolated from Laurencia claviformis . The effects of pacifenol and two derivatives on survival and feeding behaviour of the aphid Schizaphis graminum were studied. Toxicity of pacifenol was lower than the other compounds, and the dibromo derivative was more toxic than pacifidiene. At concentrations higher than 250 and 750 ppm, respectively, both compounds acted as antifeedants on aphids.

A new diterpenoid of mixed biogenesis; isoepitaondiol, has been isolated together with known diterpenoids and two chromones from the alga Stypopodium flabelliforme collected at Easter Island.

ent -4α-Hydroxy-19-norbeyer-15-ene, ent -beyer-15-en-17,19-diol, apigenin and two new diterpenes, ent -beyer-15-en-18,19-diol and 15β,16β-epoxide- ent -beyeran-18-ol were isolated from Baccharis tola .

Three new neo-clerodane diterpenoids were isolated together with other known clerodanes from Baccharis rhomboidalis . Their structures were established by spectroscopic methods.

Tropine, a pair of diastereoisomeric hygrolines and two new tropane alkaloids; 3α-senecioyloxytropan-6β-ol and 6β-angeloyloxytropan-3α-ol, were isolated from roots of Schizanthus hookeri .