Fluorinated dioxolanes. 3. Nucleophilic reactions of perfluoro-4-methyl-1,3-dioxolanes

Conclusions Perfluoro-2,4-dimethyl-2-fluorocarbonyl-1,3-dioxolane reacts with sodium carbonate to give perfluoro-2-methylene-2-methyl-1,3-dioxolane. Under the reaction conditions, the latter dimerizes to perfluoro-2-(2,4-dimethyl-1,3-dioxolan-2-ylmethylene)-4-methyl-1,3-dioxolane, and on treatment with CsF is converted into perfluoromethyl-(1,3-dioxolany-2-yl)ketone.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 938–942, April, 1989.     

Composition of lipids of the grain of opaque-2 maize

It has been established that the change in the composition of the total lipids and the fall in the fatty acid content depend on the initial maize genotype. A decrease in the amount of unsaponifiable substances in the grain of mutants is accompanied by qualitative changes in the composition regardless of the nature of the genotype.Scientific-Research Institute of Biology Dnepropetrovsk State university. Translated from Khimiya Prirodnykh Soedinenii. No. 3. pp. 360–363. May–June, 1988.     

The mass spectra of 1,1,1-trichloro-2,4-pentanedione and its Al(III), Cr(III), Fe(III), Mn(II), Co(II) and Cu(II) complexes

The compounds 1,1,1-trichloro-2,4-pentanedione, Cu(II)tca₂, Co(II)tca₂, Mn(II)tca₂, Al(III)tca₃, Cr(III)tca₃ and Fe(III)tca₃ (tca?1,1,1-trichloro-2,4-pentanedionato, [CCl₃COCHCOCH₃]^?) have been prepared and their mass spectra have been obtained. The mass spectral results have been compared with findings for comparable fluorinated and nonhalogenated compounds. Comparisons are made in terms of internal redox reactions and hard and soft acid base theory. Rearrangement of chloride from ligand to metal accompanied by the elimination of CO or other neutral even electron fragments emerges as an important reaction for the ions of these compounds. While the internal redox reactions characteristic of all previous β-diketonate complex mass spectra still occur, their importance appears reduced to some degree by the facility of the chlorine rearrangement.     

Chemistry of heteroanalogs of isoflavones

Condensation of 2-pyridylacetonitrile with polyphenols gave the corresponding -(2-pyridyl)-acetophenones, which were converted to the pyridine analogs of natural isoflavones and to 3-pyridylchromones with methyl, trifluoromethyl, and ethoxycarbonyl groups in the 2 position. The antimicrobial activity of 3-pyridylchromones and their reaction with alkylating and acylating agents and phosphorus pentasulfide were investigated.See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1180–1185, September, 1977.     

Novel polymer-bound chiral selenium electrophiles

[reaction: see text]. Polymer-bound chiral electrophilic selenium reagents have been developed and applied to stereoselective selenenylation reactions of various alkenes. Different cleavage protocols allow further functionalization of the addition products leading to improvements in selenium-based solid-phase chemistry.     

Coprecipitation/accumulation/distribution of manganese and iron, and electrochemical characteristics of Mn in calcareous seawater

A study of managanese and iron associated with particulate matter in seawaters derived from the English Channel (and North Sea). Sequential extraction procedures have been used to identify geochemical processes that govern Mn and Fe coprecipitation/accumulation/distribution in different particulate phases (carbonate; Fe-Mn(hydr)oxides; organic matter and residual phase). The oxidation states of Mn and Fe, some mechanisms of bonding and the magnetic characteristics of particles have been investigated by Mössbauer spectroscopy, electron spin resonance(ESR) spectroscopy, and mass susceptibility balance. The effect of pH and redox potential on stability of different dissolved and particulate Mn species was also examined. In the these calcareous seawaters, manganese (II) is predominantly bound to the carbonate phase (calcite) in the form of Mn_xCa_1-xCO₃. However the persistent occurrence of Mn in oxidation states > 2 in these particles has suggested the existence of manganese(III) in the polymeric FeOOH structures as an intermediate entity during Mn(II) oxidation in the sea. The activity coefficient of the entity MnOOH in FeOOH has been evaluated and p-pH diagrams of Mn have been proposed under marine conditions.     

Flavonoids of the peel of the fruit ofCitrus unshiu

Institute of Biochemistry, Academy of Sciences of the Georgian Republic, Tbilisi, and Samara Medical Institute, Russia. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 821–822, November–December, 1994.     

Use of cyclotron-produced isotopes for analytical investigation: Determination of vanadium in gallium

The extraction of the V(V)-BPHA complex into chloroform and benzene was investigated using⁴⁸V tracer produced from the⁴⁵V reaction using the Variable Energy Cyclotron, Calcutta. A neutron activation analysis procedure for the estimation of vanadium in gallium metal samples based on the extraction of V(V)-BPHA complex into benzene is given.     

Structure of phenolic stabilizers for polymers VIII. Crystal structure of 2,2′-methylenebis(4-methyl-6-ter-butylphenol) monoacrylate

L. Ya. Karpov Scientific-Research Physicochemical Institute. Scientific-Research Institute of Rubber and Latex Goods. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 5, pp. 162–164, September–October, 1991.     

Topological incremental scheme for calculating13C NMR chemical shifts in polysubstituted benzenes with substituents of one kind

A new topological approach to predicting the¹³C NMR chemical shifts of polysubstituted benzenes has been proposed (in the example case of compounds with substituents of one kind of the type C₆H_6–nX_n). The collective interactions of several substituents X [X=CH₃, C₂H₅, iso-C₃H₇, CF₃, COOH, f, Cl, Br, Si(CH₃)₃] have been expressed in the framework of a regression treatment in terms of two-particle increments. The chemical shift of each carbon atom has been represented in the form of an equation containing 17 parameters. The calculation scheme can be transformed and expanded for use even in the calculation of the spectra of compounds not previously studied. The calculated shifts for some previously investigated compounds and some compounds not previously investigated have been presented. The error in reproducing chemical shifts is equal to 0.2–0.3 ppm (and may be as high as 0.8 ppm for only a few measurements).V. I. Vernadskii Institute of Geochemistry and Analytical Chemistry, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 2, pp. 62–71, March–April, 1991.