Aspergillines A-E (1-5) are highly oxygenated cyclopiazonic acid (CPA)-derived alkaloids bearing a rigid and sterically congested hexacyclic indole-tetrahydrofuran-tetramate scaffold, isolated from the endophytic fungus Aspergillus vesicolor. Apergillines A-C represent a new subclass of CPA-derived alkaloids, and aspergillines B and E possess a butanoic acid methyl ester moiety. The structures, including absolute configuration, were elucidated by interpretation of the NMR, X-ray crystallographic, and circular dichroism data. All compounds displayed anti-TMV and cytotoxic activities.
Fistulains A and B (1 and 2), two novel bischromones with unique coupling patterns, alone with their biosynthetic related compound 3, were isolated from the bark of Cassia fistula. Fistulain A represents a new type of dimeric chromone alkaloid biogenetically derived from a chromone and a tricyclic alkaloid through an unusual C-14-N linkage. Fistulain B has a new carbon skeleton with a C-14-C-5' linkage formed between two different chromone units. Fistulain A displayed anti-TMV activity, and both 1 and 2 showed weak cytotoxicities.
Two new flavones, siameflavones A and B (1 and 2), together with five known flavones (3-7) were isolated from the stem of Cassia siamea. Their structures were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Compounds 1-5 were evaluated for their anti-tobacco mosaic virus (Anti-TMV) activity. The results showed that compounds 1-5 showed weak anti-TMV activity with inhibition rates in the range of 11.6-18.5%.
A new phenolic compound, (E)-7-(3,7-dimethylocta-2,6-dienyl)-4-methoxybenzofuran-2(3H)-one (1), was isolated from the stems of flue-cured tobacco (a variety of Nicotiana tabacum L). Its structure was elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compound 1 was tested for its anti-tobacco mosaic virus (anti-TMV) activity and it shows potential anti-tobacco mosaic virus activity with inhibition rates of 12.5 %.
Four novel manganese(II) binuclear complexes have been prepared and characterized, namely [Mn2(TCPHTA)(L)J-(C104)2 [where L is 2,2'-bipyridyl (bipy), 1,10-phenanthroline (phen), 4,4'-dimethyl-2,2'-bipyridyl (Me2bipy) or 5-nitro-l,10-phenanthroline (NO2-phen) and TCPHTA is the tetrachlorophthalate dianion]. Based on i.r. spectra, elemental analyses, conductivity measurements, extended tetrachlorophthalato-bridged structures consisting of two manganese(II) ions in which each manganese(II) ion has a distorted octahedral environment are proposed for these structures. The temperature dependence of the magnetic susceptibility for [Mn2(TCPHTA)(phen)4]-(C104)2.H20 was measured over the 4--300 K range and the observed data were successfully simulated by an equafionbased on the spin Hamiltonian operator (H = -2JS1 "$2), giving the exchange integral J = -1.05 cm-1.This result is indication of a weak antiferromagnetic spin exchange interaction between the metal ions.
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