Phosphorus, Sulfur, and Silicon and the Related Elements最新文献

A series of new 8-decylthio-10-methylthio-pyrimido[5,4-e][1,2,4]triazolo[1,5-c]pyrimidine derivatives was prepared and characterized by FTIR, ¹H NMR, ¹³C NMR, and HRMS. The bioassay results revealed that the title compounds had moderate to excellent insecticidal activities against Aphis fabae at a concentration of 500 mg/L. Among them, 8-(decylthio)-2-((4-chlorophenoxy)methyl)-5-propyl-10-(methylthio)-5,6-dihydropyrimido[5,4-e][1,2,4]triazolo[1,5-c]pyrimidine (4l) exhibited the highest insecticidal activity, with 95% mortality. Moreover, 8-(decylthio)-2-((2,4-dichlorophenoxy)methyl)-5-propyl-10-(methylthio)-5,6-dihydropyrimido[5,4-e][1,2,4]triazolo[1,5-c]pyrimidine (4i) showed broad-spectrum postemergence herbicidal activities against Abutilon theophrasti, Amaranthus spinosus, Chenopodium album, Digitaria sanguinalis, Echinochloa crusgalli, and Setaria viridis, which were equivalent to the positive control flumetsulam. However, all new synthesized compounds displayed weak fungicidal activity against four kinds of phytopathogenic fungi including Botrytis cinerea, phytophythora capsici, Elsinoe fewcetti, and Diaporthe medusaea. Compound 4l with remarkable insecticidal activity, and compound 4i with excellent herbicidal activity could be promising lead compounds for further investigation.

Potassium salts (KA, A = anion) that catalyzed the oxidative coupling of alkanethiols (RSH) to dialkyl disulfide (R₂S₂) were investigated by using sulfur as oxidant and 18-crown-6 ether as phase transfer agent under solvent-free conditions at atmospheric pressure. Crown ether (15-crown-5 ether, 18-crown-6 ether, dibenzo-18-crown-6 ether) showed excellent solid-liquid phase transfer effect in solid KA catalyzed reaction. RS⁻ is the key active species of the KA catalyzed reaction. The catalytic activity of KA is affected by the pKa of conjugated acid (HA) of anion A⁻ in KA. The larger the pKa of the corresponding HA, the more active for KA to activate RSH to generate RS⁻. Among the KA investigated, the yield of (n-C₈H₁₇)₂S₂ for the K₂CO₃, K₃PO₄·3H₂O and K₂SnO₃·3H₂O catalyzed reaction reached more than 98.0%. The yield of R₂S₂ can reach more than 95.0% by 0.1 mol% 18-C-6 (based on sulfur) and 0.1 mol% K₂CO₃ (based on sulfur) catalyzed the oxidative coupling of different alkanethiols.

A fast, safe and accessible multicomponent reaction procedure is reported for the synthesis of symmetric and nonsymmetric benzyl-bisphosphoramidate derivatives. Our key reagents were 1,3-phenylenedimethanamine 3 conjointly with the five different phosphorous chlorides, O, O′-diethyl chlorothiophosphate 1, diphenyl phosphoryl chloride 2, diethyl chlorophosphate 5, N, N, N ′, N′-tetramethylphosphorodiamidic chloride 7 and O, O′-dimethyl chlorothiophosphate 9. A total of seven products were obtained, five of them none reported before. As far as we know, our work constitutes the first approach for the synthesis of nonsymmetric benzyl-bisphosphoramidate derivatives. The presence of our adducts were always confirmed by NMR spectroscopy (¹H, ¹³C and ³¹P) and mass spectrometry.

The present work deals with a practically efficient protocol designed for the synthesis of 2,7-dibromoxanthenediones using N-bromosuccinimide (NBS) in the presence of p-toluene sulfonic acid (PTSA). A combination of NBS and PTSA in chloroform is an efficient system for selective α-bromination of xanthenediones under mild reaction conditions. The main advantage of this method is short reaction duration, mild reaction conditions, easy work up and in addition the method provides excellent yields. All the compounds synthesized were characterized by spectroscopic techniques.

Acrylic acid (AA) nanocomposite hydrogels (NCH) containing different kinds of SiO₂ nanoparticles were prepared by way of free radical polymerization. The polymerization conditions were optimized considering the initiator and monomer concentrations in the mixture, as well as the reaction temperature and time. SiO₂ nanoparticles were used in original (neutral), NH₂ modified (hydrophilic) and perlite forms. Nanocomposite hydrogels that contain NH₂ modified nano-SiO₂ were found to present swelling values higher than those of the original acrylic acid nanocomposite hydrogel and the nanocomposite hydrogel that contain original SiO₂. AA-perlite nanocomposite hydrogels were used to achieve the best thermal stability, although the perlite-doped hydrogels exhibit less swelling due to the large particle size of perlite and its lower SiO₂ content. FESEM and mapping analyses were conducted to verify the incorporation of SiO₂ nanoparticles into the hydrogel structure. Amorphous structures were determined by an XRD analysis. Thermal stability of hydrogels was measured by TG-DTA. The thermal stabilities of NH₂-modified SiO₂- and perlite-doped nanocomposite hydrogels were found to be higher than those of plain hydrogel and original SiO₂-doped nanocomposite hydrogels.

Tert-butyl-λ⁵-phosphanedione was generated by flash vacuum thermolysis (FVT) of trimethylsilyl tert-butyl phosphonohalidates. The structure of tert-butyl-λ⁵-phosphanedione was confirmed by chemical reactions. Tert-butyl-λ⁵-phosphandione readily undergoes trimerization, enters into the [2 + 3] - cycloaddition reaction with 2-phenyloxirane and adds alcohols.

A preparatively convenient one-pot method for the synthesis of new 7-thioxo[1,3]thiazolo[3,2-c]pyrimidine derivatives 3a–3l by the cyclocondensation of 5-methyl(1,3-thiazolidin-2-ylidene)ketones 1a–1c with aroyl 2a–2d and 2-thienyl 2e isothiocyanates for 6–10 h boiling in acetone has been developed. Studies of the antimicrobial and antioxidant activities potential of the obtained compounds revealed that [2-methyl-5-(4-nitrophenyl)-7-thioxo-2,3-dihydro-7H-[1,3]thiazolo[3,2-c]pyrimidine-8-yl](phenyl)methanone 3k, effect on the test culture of M. luteum at a concentration of 0.5% is close to the control drug vancomycin. Moreover, [5-(4-bromophenyl)-2-methyl-7-thioxo-2,3-dihydro-7H-[1,3]thiazolo[3,2-c]pyrimidin-8-yl](phenyl)methanone 3j has an antibacterial effect on the specified test culture at a minimum inhibitory concentration of 15.6 μg/mL. In turn, 1-(2-methyl-5-(thiophen-2-yl)-7-thioxo-2,3-dihydro-7H-[1,3]thiazolo[3,2-c]pyrimidin-8-yl]ethanone 3d can be considered promising for further structural modification to enhance the antioxidant effect. The structure of all synthesized substances was established by spectral analysis (¹H and ¹³C NMR, LC–MS, and FT-IR). Additionally, the structure of compound 3i was confirmed by X-ray diffraction analysis.

Phosphate glasses are characterized by properties distinguished by comparison with those of others such as borates, silicates, and tellurides that can be used in many fields such as optics, electronics, medicine, environmental protection, etc. This study aims to discover the effect of the europium dopant on the structural properties of glasses with 65% P₂O₅ – (35-x) % SrO – x% Eu₃O₂ (where x = 0.5, 1, 1.5, 2 mol at. %) using molecular dynamics simulations. The density of simulated glasses was found to increase from 2.784 to 2.860 g/cm³ according to the gradual increase in the europium content. The Eu-O distances and coordination numbers are found to be in the ranges of 2.18–2.21 Å and 6.59–6.79, respectively. The Sr-O coordination numbers were found to decrease from 7.30 to 6.55 with an increase in the europium content in the phosphate glasses. The coordination of the Eu-Eu pair increases from 0.07 to 0.23 with increasing europium concentration in phosphate glasses, but it remains weak, which is a sign of good solubility of europium in the glass matrix, as expected by experiments and the literature. Studies of the cluster statistics in the simulated glasses demonstrate that most europium atoms are found isolated or in a doublet.

The regioselectivity of halogenation of terminal and internal thioethers of 7-(trifluoromethyl)quinazolin-4(3H)-ones was investigated. It is proven that the direction of halocyclization of allyl thioethers depends on the presence of a substituent at the terminal carbon atom of the allyl moiety. The cyclization of allyl, methallyl and prenyl thioethers leads to the annulation of thiazole cycle with the formation of thiazolo[3,2-a]quinazolinium trihalides while cyclization of cinnamyl thioether forms thiazino[3,2-a]quinazolinium trihalides with the additional thiazine cycle.

In this article, we show that tribromide heterogenized on the surface of silica-coated magnetic nanoparticles modified with N²,N4,N⁶-tris(aminomethyl)-1,3,5-triazine-2,4,6-triamine [Fe₃O₄@SiO₂-tris(triazine-triamine)-Br₃] is a novel and efficient reusable nanocatalyst for the oxidation of sulfides to sulfoxides and oxidative coupling of thiols to disulfides using hydrogen peroxide as green oxidant. The structure of the as-fabricated Fe₃O₄@SiO₂-tris(triazine-triamine)-Br₃ was characterized by a series of spectroscopic techniques including FT-IR spectroscopy, SEM, TEM, EDX, VSM, XRD and TGA techniques. TEM and SEM analysis confirmed that the typical silica shell thickness was assessed to be around 20 nm. Recycling studies revealed that the Fe₃O₄@SiO₂-tris(triazine-triamine)-Br₃ could be easily recovered by a simple magnetic separation and recycled at least 6 times without deterioration in catalytic activity.