One‐Pot Synthesis of Tetraalkyl Benzene‐1,2,3,5‐tetracarboxylates from a Four‐Component Reaction of Alkyl Propiolates and Alkyl 2‐Nitroethanoates Promoted by Ph3P

Alkyl 2‐nitroethanoates react with alkyl propiolates in the presence of triphenylphosphine (Ph₃P) in a mechanistically unprecedented reaction to afford tetraalkyl benzene‐1,2,3,5‐tetracarboxylates in moderate yields (36–42%).     

Synthesis,single crystal structure determination,and solution behavior of an 8-hydroxyquinoline derivative of niobium(V) ethoxide

An 8-hydroxyquinoline derivative of niobium(V) ethoxide was synthesized and characterized by elemental analysis, mass spectrometry, infrared, electronic, and ¹H, ¹³C, and ⁹³NMR spectroscopies. Tetraethoxy(8-quinolinato)niobium(V), as shown by the single crystal structure determination, exists as an octahedral compound in the solid state in which the 8-quinolinato group chelates to the metal atom. In solution, this group partially becomes unidentate; the six-coordinate species is in equilibrium with the five-coordinate species, as shown by ⁹³Nb and variable-temperature ¹H NMR spectroscopy.     

An efficient synthesis of spiro[dibenzo[b,i]xanthene-13,3′-indoline]-pentaones and 5H-dibenzo[b,i]xanthene-tetraones

Spiro[dibenzo[b,i]xanthene-13,3′-indoline]-pentaones and 5H-dibenzo[b,i]xanthene-tetraones are synthesized from the condensation of 2-hydroxynaphthalene-1,4-dione with isatins or aldehydes.     

Electrodeposition of a copolymer nanocomposite for the headspace solid-phase microextraction of benzene,toluene, ethylbenzene and xylenes

In this study, polyaniline-co-poly(o-toluidine)/graphene oxide nanosheets composite was electrodeposited on the surface of a stainless steel wire as a new coating for headspace solid-phase microextraction of benzene, toluene, ethylbenzene and xylenes (BTEX) with gas chromatography–mass spectrometry. The characteristics of the new coating were evaluated by the scanning electron microscopy and Fourier transform infrared spectroscopy. To study the coating performance, the influence of various parameters such as deposition potential and time, concentration of the monomers and GONSs, desorption temperature and time, extraction temperature and time and ionic strength on BTEX extraction efficiency was investigated. At the optimum conditions, the linear ranges and detection limits (S/N?=?3) were found 0.01–50 and 0.001–0.05 ng mL^?1, respectively. The intra-day and inter-day relative standard deviations (RSDs) at 0.5 ng mL^?1 concentration level (n?=?5) using a single-fiber were from 5.4 to 8.3 and 7.5 to 10.3%, respectively. The fiber-to-fiber RSDs % (n?=?3) was between 8.4 and 12.5%. Finally, the development method was applied to the analysis of various real samples.     

Solvent‐Free Synthesis of Diphenyl [2‐(Aminocarbonyl)‐1,2‐dihydroisoquinolin‐1‐yl]phosphonates from Isoquinoline,Isocyanates, and Diphenyl Phosphonate

The 1 : 1 intermediates generated by addition of isoquinoline to isocyanates were trapped by diphenyl phosphonate to yield diphenyl [2‐(aminocarbonyl)‐1,2‐dihydroisoquinolin‐1‐yl]phosphonates in good yields under solvent‐free conditions.     

Effect of Sorbent Additives to Copper-Contaminated Soils on Seed Germination and Early Growth of Grass Seedlings

Heavy metal and metalloid-contaminated soil is a serious barrier to colonization for many plant species. The problem of the elimination of toxic waste accumulated in technogenous soils in many highly transformed regions is extremely important. Hence, another attempt was made to analyze the effect of the addition of sorbents (BCH—biochar, B—bentonite, ChM—chicken manure, OS—organo-zeolitic substrate) to contaminated copper soil on the germination and early growth of Eurasian common grass species (Agrostis capillaris, A. stolonifera, Festuca rubra and Poa pratensis), which could potentially be used in recultivation. This experiment was based on the laboratory sandwich method. Standard germination indexes, morphometry and biomass analysis were used. The percentage of germinating seeds was lower in each of the soil variants and sorbents used compared to the control. Dry mass was positively stimulated by all sorbents. The response to the addition of sorbents, expressed as the electrolyte leakage of seedlings, was different depending on the species and type of sorbent. Among all sorbents, the most positive effects on germination and growth were observed in the case of OS. Overall, the response to the addition of sorbents was different in the studied species, depending on their stage of development.