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  • Author: Zhi-Yu Ni x
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Abstract

Room-temperature ionic liquids (RTILs) have recently received increasing attention as solvent alternatives for possible application in spent fuel reprocessing, particularly in the extraction of metal ions from high-level radioactive aqueous waste, due to their unique physical and chemical properties. Herein, the solvent extraction of the uranyl ions (UO2 2+) was performed using N,N′-diethyl-N,N′-di(para)tolyl-dipicolinamide (Et(p)TDPA) as the extractant in a commonly used ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]). The effects of vortexing time, phase ratio and the concentration dependence of Et(p)TDPA, nitric acid and sodium nitrate on the extraction were studied in detail. The extraction mechanism was deduced based on the slope analysis and UV-vis measurement. The distribution ratio of U from 3 mol/L nitric acid by 0.3 mol/L EtTDPA/C4mimPF6 is found to be almost 100. Conventional log-log plot analysis of the extraction equilibrium data suggests that the ions are extracted as a complex in 2:3 ratio of UO2 2+ to extractant, and the extraction most likely occurs by a cation-exchange mode since the concentration of C4mim+ in the aqueous phase increases linearly with the percent extraction of UO2 2+ evidenced by UV-vis measurement. This work promises to provide new efficient media based on RTILs for separation of uranium from the radioactive aqueous waste.

Two new phytoecdysteroids with a 20,22-acetal group were identified for the first time from the needles of the Canadian yew, Taxus canadensis. Their structures were characterized as ponasterone A 20,22-p-hydroxybenzylidene acetal (1) and ponasterone A 20,22-acetonide (2) on the basis of 1D, 2D NMR evidence and high-resolution FABMS analysis

Diabietane ether (1), a new abietane dimer connected by an ether linkage, and two known abietane diterpenoids (2 and 3) were isolated from the needles of Taxus cuspidata.

Sinenxan H [2α,14β -diacetoxytaxa-4(20),11-diene-5α, 10β -diol, 1] was isolated from the heartwood of Taxus cuspidata, for the first time from natural sources. Compound 1 was found to be readily converted into 2α-acetoxytaxa-4(20),10,12(18),13-tetraen-5α-ol (2), the first example of a taxane with 10,11- and/or 13,14-double bond(s) and a conjugated triene system, in CDCl3.

Abstract

The genus Ajuga, a member of the Lamiaceae family, is comprised of more than 300 species of annual and perennial herbaceous flowering plants mainly distributed throughout the temperate regions of Asia, Europe, Australia, North America and Africa. These plants are used as folk medicines effective for rheumatic fevers, dysentery, malaria, hypertension, diabetes and gastrointestinal disorders, as well as anthelmintic, astringent, febrifuge diuretic, antifungal and anti-inflammatory agents. A variety of constituents has been isolated from these plants. This review summarizes the phytochemical progress of the genus Ajuga and lists the compounds isolated up to 2014.

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Eight sesquiterpene lactones were isolated from the roots of Inula helenium and fl owers of I. japonica. Among them, isoalantolactone () and santamarine (6) exhibited significant growth inhibitory activities against gynecologic cancer cell lines, while others weakly inhibited the growth of the cell lines (IC50 ≤ 100 μM). In addition, 3 significantly inhibited the tumour growth of S180 tumour-bearing mice. Compounds 3 and 6 were not toxic to human embryonic lung fibroblast cells in vitro. These results demonstrated that the antitumour activities are closely related to the structures of the compounds, that is, an α-exomethylene- γ-lactone ring is necessary for these activities.

Ten 1,10-secoguaianolides were isolated from the flowers of Achillea millefolium. Their structures were determined on the basis of spectroscopic methods. Three of them (millifolides A-C) including two dimeric sesquiterpenoids exhibit new skeletons. Seco-tanapartholide A exhibited moderate cell growth inhibitory activity against the human cancer cell line MCF7WT (IC50 = 5.51 μm) in vitro.