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Lawesson’s reagent reacted with racemic diethyl malate to yield O-(1,2-bis(ethylcarboxylate)ethyl-1 4-methoxyphenyl dithiophosphonic acid. The acid formed pyridinium dithiophosphonate salts with 3-(hydroxymethyl)pyridine, pyridoxine, and (S)-(–)-nicotine. The salts revealed antifungal activity against Candida albicans. [ABSTRACT FROM AUTHOR]

Wind turbines and their associated parts are subjected to cyclical loads, such as bending, torque, longitudinal stresses, and twisting moments. The novel spatiotemporal reliability technique described in this research is especially useful for high-dimensional structural systems that are either measured or numerically simulated during representative observational time span. As this study demonstrates, it is possible to predict risks of dynamic system failure or damage given the in situ environmental load pattern. As an engineering example for this reliability, the authors have chosen 10-MW floating wind turbines and their dynamic responses, under environmental loadings, caused by wind and waves. The aim of this study was to benchmark a state-of-the-art approach suitable for the reliable study of offshore wind turbines. Existing reliability methods do not easily cope with dynamic system high dimensionality. The advocated reliability technique enables accurate and efficient assessment of dynamic system failure probability, accounting for system nonlinearities and high dimensionality as well as cross-correlations between different system components. [ABSTRACT FROM AUTHOR]

A new series of chiral carboxypyridinium dithiophosphates were synthesized by the reactions of nicotinic, isonicotinic, and picolinic acids with dithiophosphoric acid on the basis (1S)-endo-(–)-borneol in benzene or ethanol. 5,5-Dimethyl-2-mercapto-2-thiono-1,3,2-dioxaphosphorinane reacted with 3-hydroxypyridine or 3-pyridinemethanol in EtOH to afford the 3-hydroxypyridinium and 3-hydroxymethylpyridinium 5,5-dimethyl-2-mercapto-2-thiono-1,3,2-dioxaphosphorinanes which possessed antifungal activity against Candida albicans. [ABSTRACT FROM AUTHOR]

A novel methodology to accelerate annulation reactions leading to condensed selenium heterocycles was developed. The reactions of selenium dihalides with methyleugenol, allyl thymyl ether, allyl 1-naphthyl and 1-naphthyl propargyl ethers were carried out in the presence of alcohols, which considerably accelerated the annulation reactions. In solvent systems CH2Cl2/MeOH or CHCl3/MeOH, the reactions proceeded as annulation–methoxylation affording condensed methoxylated heterocycles. In the presence of isopropanol, the reactions were not accompanied by alkoxylation giving condensed halogen-containing products. The annulation reaction of selenium dihalides with 1-naphthyl propargyl ether included stereoselective anti-addition to the triple bond. The efficient selective synthesis of the first representatives of novel families of condensed selenium heterocycles with promising biological activity was developed. [ABSTRACT FROM AUTHOR]

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The ongoing growth and digitalization of Arctic shipping strengthen the relevance of the models for ship performance prediction. Most of existing models consider ice thickness, total concentration, and other geometrical parameters of ice, while the change of ice flexural strength is usually neglected. This article aims at answering the question of how the flexural strength of level ice depends on the season and region of the Arctic, and on how this variation influences the ice performance of a ship. For this purpose, we developed a method to estimate the properties of ice of a given thickness based on the data on natural conditions in a certain region. Sensitivity analysis of this method showed that seasonal and regional changes in the flexural strength of ice could be predicted using the data on air temperature and seawater salinity. The available climatic data allowed us to analyze a spatiotemporal variability of these two parameters in the Russian Arctic. To predict the performance of constructed ships in ice, we developed a resistance scaling approach. Its accuracy was examined using full-scale data, ice tank tests, and numerical model results for 21900M-type icebreakers. This study concludes that variation of ice properties significantly affects ice performance of a ship and should be considered when simulating year-round navigation in the Arctic. • Article proposes a method to estimate the mechanical properties of ice based on environmental parameters. • Seasonal and regional variation of ice strength may be predicted based on the data on air temperature and seawater salinity. • Change of ice properties depending on the region and season is significant and should be considered in simulation studies. • The developed resistance scaling approach allows making robust estimates of ice performance of constructed ships. [ABSTRACT FROM AUTHOR]

The regioselective synthesis of novel functionalized condensed organochalcogen compounds by chalcogenocyclofunctionalization reactions based on chalcogen halides and the natural products thymol and carvacrol has been developed. The reactions of selenium dibromide with allyl thymol and allyl carvacrol proceeded in methylene chloride at room temperature in the presence of NaHCO3 affording bis[(7-isopropyl-4-methyl-2,3-dihydro-1-benzofuran-2-yl)methyl] and bis[(4-isopropyl-7-methyl-2,3-dihydro-1-benzofuran-2-yl)methyl] selenides in 90–92% yield. Similar sulfides were obtained in 70–72% yields by the reaction of sulfur dichloride in chloroform under reflux. Trihalotellanes containing the same organic moieties were synthesized from allyl thymol, allyl carvacrol and tellurium tetrachloride or tetrabromide in quantitative yields. Corresponding functionalized ditellurides were prepared in 91–92% yields by the reduction of the trichlorotellanes with sodium metabisulfite in two-phase solvent system. The comparison of reactivity of sulfur, selenium and tellurium halides in chalcogenocyclofunctionalization and distinguishing features of each reaction were discussed. [ABSTRACT FROM AUTHOR]

The original goal of this research was to study stereochemistry of selenium dihalides addition to cycloalkenes and properties of obtained products. Remarkable alkene-to-alkene and alkene-to-alkyne transfer reactions of selenium dibromide and PhSeBr were discovered during this research. The adducts of selenium dibromide with alkenes or cycloalkenes easily exchange SeBr2 with other unsaturated compounds, including acetylenes, at room temperature, in acetonitrile. Similar alkene-to-alkene and alkene-to-alkyne transfer reactions of the PhSeBr adducts with alkenes or cycloalkenes take place. The supposed reaction pathway includes the selenium group transfer from seleniranium species to alkenes or alkynes. It was found that the efficient SeBr2 and PhSeBr transfer reagents are Se(CH2CH2Br)2 and PhSeCH2CH2Br, which liberate ethylene, leading to a shift in equilibrium. The regioselective and stereoselective synthesis of bis(E-2-bromovinyl) selenides and unsymmetrical E-2-bromovinyl selenides was developed based on the SeBr2 and PhSeBr transfer reactions which proceeded with higher selectivity compared to analogous addition reactions of SeBr2 and PhSeBr to alkynes under the same conditions. [ABSTRACT FROM AUTHOR]