A. V. Il’yasov

Dimephosphone analogs: a pharmacological aspect

We studied some pharmacological properties of dimephosphone P—C and aza analogs, viz., dimethyl (2-methyl-4-oxopent-2-yl)phosphonate, which is one of the first organophosphorus drugs having no anticholinesterase activity. Replacement of two P—O—C fragments in dialkyl (2-methyl-4-oxopent-2-yl)phosphonates with the P—C ones on going to dialkyl-(2-methyl-4-oxopent-2-yl)phosphine oxides results in a dramatic decrease in the acute toxicity of the latter to warmblooded animals. The toxicities of dimephosphone aza analogs and (γ-oxoalkyl)phosphine oxides under study depend on the nature of aza fragment introduced instead of the oxygen atom. Dimephosphone pyridinoylhydrazones were found to exhibit a high antiinflammatory activity, which increases the interest for this type compounds as promising tuberculostatics.

129Xe NMR in study of tissues and plants

The high sensitivity of the129Xe nuclear magnetic resonance (NMR) chemical shift to the environment was used for characterization of biological tissues and plants. The xenon gas was dissolved under moderate pressure by means of a special device in small pieces of human and animal tissues (heart, muscle, lung, kidney, liver, spleen, brain, sinew, cartilage and hypodermic fat) or plants (leaves, stems, grains, fruits) and the NMR parameters were measured in vitro. The observed line with the chemical shift ∼ 180 ppm was attributed to the xenon located in various cellular structures such as lipid shells, intracellular formations. A xenon spectrum in the lungs obtained in vitro coincides with that in the lungs of a mouse measured in vivo by other investigators. The NMR parameters were found to reveal noticeable distinctions between normal and tumour-affected tissues. The analysis of the129Xe NMR spectra of the sinew and the cartilage revealed the dependence of the magnetic parameters on the age of the substance. This fact could be accounted for by the changes of the absorption ability of a biological system due to age transformations. The results obtained in comparison with biochemical data reveal the promissory outlook of129Xe NMR for the investigation of the state of biological tissues and for medical diagnostics.

WIN-DAISY: Application to oriented molecules. Analysis and simulation of NEMA-NMR spectra

The1H-NMR spectra of 3-methyl-3-cyano-cyclopropene and19F-NMR spectra of bis-trifluoromethyl-mercury have been measured in nematic liquid crystal EBBA and in mixture of EBBA+M MBBA, respectively. The novel program systemWIN-DAISY was used for automated analysis and simulation of NMR spectra, and optimised parameters for dipolar coupling constants extracted.

Simultaneous electrochemical and electron paramagnetic resonance studies of fullerene anion radicals C 60 1− and C 60 3−

Simultaneous electrochemical and electron paramagnetic resonance experiments have been carried out on the reduced C60 fullerene to examine theg-factor assignment of the radical species. C601− and C603− show the following EPR characteristics at room temperature: C601−:g1−=2.0002±0.0001, 2ΔB1s=0.17 mT, and C603−:g3−=2.0008±0.0002, 2ΔB1s=0.07 mT. EPR linewidths are apparently narrower compared to those in most of the spectra previously reported. Variable temperature EPR study on solution containing C601− has shown thatg1− value is not while the linewidth is only slightly temperature dependent.

ESR parameters and transformations of the products of reduction of methanofullerenes

Paramagnetic products of chemical (by diazabicycloene derivatives) and electrochemical reduction of the dicarbethoxy derivative and phosphorylated methane[60]fullerenes were studied by ESR. In all cases, one-electron reduction affords radical anions (g = 1.9998—1.9999, ΔH = 0.20—0.28 mT), and further reduction produces the secondary radicals (g = 2.0004—2.0010, ΔH = 0.020—0.028 mT). The rate constants for formation and decay of the radical anions in chemical reduction depend slightly on the nature of the reducing agent and substituents in the methanofullerenes. The retro-Bingel reaction occurs during two-electron reduction.

Investigation of electron transfer processes in organic molecules and metal complexes by means of electrolysis-EPR

Kinetics of electrochemical reduction of trialkylphosphates, slow homogeneous electron transfer reaction with the participation of paramagnetic intermediates and multispin Co(II)-, Cu(II)-, Zn(II),-nitroxyde radical systems reduction processes are studied with the help of combining electrochemical method and EPR.

Dimephosphone analogs: II. Dialkyl(diaryl)-(2-methyl-4-oxopent-2-yl)phosphine oxide oximes: Synthesis, structure, and generation of iminoxyl radicals

Dialkyl(diaryl)-(2-methyl-4-oxopent-2-yl)phosphine oxide oximes have been synthesized for the first time. According to the X-ray diffraction data, these compounds in crystal exist as a single E isomer. Their structure in solution and the E/Z isomer ratio were determined by 1H and 13C NMR spectroscopy.

ESR study of some iminoxy free radicals generated from phosphorylated oximes and dioximes

The new type of phosphoniminoxy free radicals was generated electrochemically or by chemical oxidation of oximes. It was established the strong difference of ESR parameters for isomeric Z and E forms of the radicals. The spin distribution and its correlation with electronic and spatial characteristics of molecules as well as with intramolecular interactions are discussed.

Measurement of the coefficient of translational diffusion in liquid solutions by means of EPR

A new method of diffusion coefficient measurement in liquids under electrolysis is considered. It is shown that the diffusion parameters can be correctly determined from the dependence on the electrolysis time of the EPR signal intensity of the ion radicals formed.

N-alkyl-2-halo- and 2,2-dihaloaldimines in the Pudovik reaction

The use of N-alkyl-2-haloaldimines in the imine version of the Pudovik reaction, namely, in the reaction of imines with acid esters of phosphorus acids, much extended the synthetic potential of this reaction due to the fact that the primary addition and protonation product, having quite a mobile single hylogen atom, can undergo both spontaneous transformations and transformations involving other reagents. The reduction of the С–Hlg bond in N-alkyl-2-halo- and -2,2-dihaloaldiminium salts with О,О-dialkyl phosphorodithioic acids was observed for the first time.