Sorption of stable and radioactive Cs(I), Sr(II), Co(II) ions on Ti–Ca–Mg phosphates

Journal of Radioanalytical and Nuclear Chemistry - In this paper, we studied the features of stable and radioactive Cs(I), Sr(II) and Co(II) ions sorption on Ti–Ca–Mg phosphates. The...     

Humulene Diepoxides from the Australian Arid Zone Herb Dysphania: Assignment of Aged Hops Constituents

Dysphania is an abundant genus of plants, many of which are endemic to the Australian continent, occurring primarily in arid and temperate zones. Despite their prevalence, very few investigations into the phytochemistry of native Dysphania have been undertaken. Described herein, is the isolation and elucidation of two enantiomeric diastereomers of humulene diepoxide C from D. kalpari and D. rhadinostachya, of which unassigned diastereomers of humulene diepoxide C have been previously reported as components in beer brewed from aged hops. In addition, two (+)-humulene diepoxiols (humulene diepoxiol C-I and C-II) were isolated from D. rhadinostachya. Analysis of Chinook hops oil confirmed the presence of both humulene diepoxide C-I and C-II as trace components, and in turn enabled GC-MS peak assignment to the relative stereochemistry. Anticancer assays did not reveal any significant activity for the (+)-humulene diepoxides. Antifungal assays showed good activity against a drug-resistant strain of C. auris, with MIC₅₀ values of 8.53 and 4.91 μm obtained for (+)-humulene diepoxide C-I and C-II, respectively.     

A 14 Parameter Study of UHPLC’s for Method Development Transfer and Troubleshooting

Five ultra-high pressure liquid chromatography (UHPLC) instruments were compared to one another by examining the overall system performance and key functions of the system parts including: pump, auto-sampler, thermo-stated column compartment, and the detector. The five UHPLC systems used in this study were: ThermoFisher Vanquish, Agilent 1290 Infinity I, Agilent 1290 Infinity II, Waters Acquity I-Class, and Shimadzu Nexera X2. The identities of the systems were blinded in the results and discussion section to use this study for scientific purposes only rather than for competition and marketing. The following tests were performed to evaluate and compare the five UHPLC systems: injector linearity and precision, sample carryover, sample (autosampler) temperature accuracy, column temperature accuracy and precision, pressure ripple, pump mixing accuracy, flow rate accuracy, detector drift and noise, detector linearity, wavelength accuracy, extra-column volume, and dwell volume determination. This study presents an approach on how to test the performance of UHPLC systems along with potential problems that analysts may face when using the UHPLC systems, examples of such issues are: retention time irreproducibility, low sensitivity, method transfer failure, etc.     

Asymmetric Total Synthesis of (−)‐Erogorgiaene and Its C‐11 Epimer and Investigation of Their Antimycobacterial Activity

A short, nine‐step, highly enantioselective synthesis of (?)‐erogorgiaene and its C‐11 epimer is reported. The key stereochemistry controlling steps involve catalytic asymmetric crotylation, anionic oxy‐Cope rearrangement and cationic cyclisation. (?)‐Erogorgiaene exhibited promising antitubercular activity against multidrug‐resistant strains of Mycobacterium tuberculosis.     

Beyond the Dimer and Trimer: Tetraspiro[2.1.25.1.29.1.213.13] hexadecane‐1,3,5,7‐tetraone—the Cyclic Tetramer of Carbonylcyclopropane

Tetraspiro[2.1.2⁵.1.2⁹.1.2¹³.1³]hexadecane‐1,3,5,7‐tetraone 4 , a unique tetraketone containing a cyclooctane core and four spiroannelated cyclopropane moieties, represents the previously unknown cyclotetramer of carbonylcyclopropane. For this purpose oxidation of the parent polyspirocyclic hydrocarbon was examined under various oxidative conditions, and the reactivity of oxidants towards methylene groups of the eight‐membered cycle, activated by adjacent spirocyclopropane rings, was evaluated and contrasted. Whereas the treatment of tetraspirohexadecane with ozone resulted in monooxidation, its reaction with methyl(trifluoromethyl)dioxirane afforded the product of four‐fold oxidation, triketoalcohol 10 . Subsequent oxidation of the latter with Dess–Martin periodinane gave the target tetraketone 4 .     

Chemical Industry,the Environment,and Russian Provincial Society: The Case of the Kokshan Chemical Works (1850–1925)

This article explores interactions between the chemical industry, the environment, and Russian provincial society in the late nineteenth and early twentieth centuries, using the example of the Kokshan chemical works, in the Elabuga District, Viatka Province, Russian Empire (today Mendeleevsk District, Republic of Tatarstan, Russian Federation). The plant’s location facilitated its rapid development due to a number of factors, including a cheap labour force, the availability of raw materials, and the absence of local competition. However, the factory’s development came in conjunction with the deterioration of the environment and subsequent health problems for employees and the surrounding population. Conflicts connected with the Kokshan works illustrate differences between this case and similar examples in Russia and Europe. In Viatka Province, the local community remained mostly silent regarding these issues, and made no demands for improving sanitary control and working conditions or reducing pollution; rather, it was distant activists who personally suffered no harm who intervened in the interest of social justice. The history of the company reflects the contrast between the transfer of European technological innovations to Russia and laborious efforts to increase national wealth on the one hand, and the exploitation of the environment and endangerment of workers’ health on the other.