Absolute configuration of seco-eudesmanolide inuloxin D from experimental and predicted chiroptical studies of its 4-O-acetyl derivative.

Sesquitepenoids inuloxins A-D, belonging to different subgroups, were isolated from Dittrichia viscosa and showed potential biocontrol of some parasitic plants as Pelipanche, Orobanche, and Cuscuta species. The absolute configurations of the first three inuloxins A-C were previously determined by using experimental and computational chiroptical spectroscopic methods. The absolute configuration of inuloxin D remains to be established.

Phaseocyclopentenones A and B, Phytotoxic Penta- and Tetrasubstituted Cyclopentenones Produced by , the Causal Agent of Charcoal Rot of Soybean in Argentina.

Two new penta- and tetrasubstituted cyclopentenones, named phaseocyclopentenones A and B ( and ), together with guignardone A (), were isolated from cultures. The phytopathogenic fungus was isolated from infected soybean tissues showing charcoal rot symptoms in Argentina. Charcoal rot is a devastating disease considering that soybean is one of the main legumes cultivated in the world.

Drophiobiolins A and B, Bioactive Ophiobolan Sestertepenoids Produced by .

Two new bioactive ophiobolan sestertepenoids, named drophiobiolins A and B ( and ) were isolated from , a fungus proposed as a mycoherbicide for biocontrol of They were isolated together with ophiobolin A, the main metabolite, 6--ophiobolin A, 3-anhydro-6--ophiobolin A, and ophiobolin I. Drophiobolins A and B were characterized by NMR, HRESIMS, and chemical methods as 7-hydroxy-7-(6-hydroxy-6-methylheptan-2-yl)-1,9a-dimethyl-3-oxo-3,3a,6,6a,7,8,9,9a,10,10a-decahydrodicyclopenta [][8]annulene-4-carbaldehyde and 6-(hydroxymethyl)-3',9,10a-trimethyl-5'-(2-methylprop-1-en-1-yl)-3a,4,4',5',10,10a-hexahydro-1,3'-spiro[dicyclopenta[,] [8]annulene-3,2'-furan]-5,7(2,9a)-dione. The relative configuration of drophiobolins A and B, which did not afford crystals suitable for X-ray analysis, was determined by NOESY experiments, while the absolute configuration was assigned by comparison of their experimental and TDDFT calculated electronic circular dichroism (ECD) spectra.

Inuloxin E, a New Seco-Eudesmanolide Isolated from , Stimulating Seed Germination.

A new sesquiterpenoid belonging to the subgroup seco-eudesmanolides and named inuloxin E was isolated from , together with the already known sesquiterpenoids inuloxins A-D and α-costic acid. Inuloxin E was characterized by spectroscopic data (essentially NMR and ESI MS) as 3-methylene-6-(1-methyl-4-oxo-pentyl)-3a,4,7,7a-tetrahydro-3-benzofuran-2-one. Its relative configuration was determined by comparison with the closely related inuloxin D and chemical conversion of inuloxin E into inuloxin D and by the observed significant correlation in the NOESY spectrum.