Synthesis of ω- and (ω – 1)-acetylenic acids from five-, six-, or seven-membered cycloalkanones

A convenient method for the synthesis of - and ( – 1)-acetylenic acids involves free-radical oxidative scission of cycloalkanones containing five-, six, or seven-membered cycles to give the corresponding -olefinic acids followed by bromination of the latter and subsequent dehydrobromination under the action of alkalis.     

Thermal polymerization of acrylamide during the formation of the structures of acrylamide complexes with metal nitrates

The effects of the composition of Mn^II, Co^II or Ni^II nitrate hydrate — acrylamide (AAM) mixtures and of the duration of their aging at ambient temperature on the structurization of acrylamide complexes and on the character of their thermal polymerization have been studied by scanning and isothermic differential calorimetry. Structurization is a rather prolonged step in the synthesis of acrylamide complexes. The peculiarities and rate of this step are determined by the composition of the mixture and by the nature of the complexforming compound; it yields several structural modifications of the AAM complexes. The thermal polymerization of those structural forms of acrylamide complexes that polymerize at low temperatures may be formally described as polymerization in an acrylamide-nitrate-water mixture. The effective activation energy of the polymerization of acrylamide mixed with Mn^II nitrate hydrate is 45 kJ mol^–1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 679–683, April, 1995.This work was carried out with financial support from the Russian Foundation for Basic Research, Project No. 93-03-4162.     

Detection and assessment of citrus tristeza virus antigens by computer-aided scanning densitometry

Citrus tristeza virus (CTV) extracted from Etrog citron (C.medica L.) was immunoprecipitated. The immunoprecipitate was fractionated by SDS-PAGE and western blotted onto nitrocellulose. The CTV antigens were determined by immunoblot analysis using rabbit anti-CTV IgG, and the protein-band pattern exhibited on the nitrocellulose was assessed by soft-laser scanning densitometry. The densitometric tracing revealed the presence of bands that were not visible to the naked eye. Using the superimposition mode of the instrument, it was also revealed that the protein-band patterns of different CTV samples were not identical. Computer-aided soft-laser scanning densitometry proved to be a powerful approach in the detection and assessment of protein bands revealed on nitrocellulose immunoblots, which we were previously unable to do employing conventional methods.     

Synthesis of 1,2,4-substituted hexahydropyridazines and X-ray structural investigation of 4-hydroxyimino-2-methyl-1-phenethylhexahydropyridazine

A series of new 1,2,4-substituted hexahydropyridazines was prepared in order to evaluate qualitatively and quantitatively the role and influence of substituents on the biological activity of this system. An X-ray structural investigation of 4-hydroxyimino-2-methyl-1-phenethylhexahydropyridazine was performed. The compounds considered exhibit moderate local anesthetic, antihistaminic, and anticonvulsive activity.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 539–541, March, 1993.     

Image analysis in the electron microscopy of cellulose protofibrils II. Digital correlation methods

Electron micrographs of parallel arrays of negatively stained ramie cellulose protofibrils were analyzed using the two-dimensional digital autocorrelation function (ACF). The method is based upon the statistical analysis of images in real space. The ACF shows strong parallel streaks of high correlation, and the lateral distance between adjacent streaks allows the mean interfibrillar distance to be estimated as 3.7 nm. The intensity profile along the streaks shows a weak modulation with peaks occurring at integral multiples of 3 or 6 nm. These results provide direct evidence that there is a regular axial texture in the protofibrils, and corroborate the conclusions previously drawn from optical diffraction analysis. Using the difference vectors found in the ACF it has been possible to reduce the picture noise level by linear integration, thereby obtaining an enhanced image. A preliminary result obtained in this way suggests that the projected protofibril morphology associated with the observed axial periodicity is a ribbon-like zigzag structure. Possible applications of the method for future work are discussed.     

Gas chromatographic system equipped with a mass detector and a selective nitrogen-phosphorous detector operating simulataneously in the analysis of pesticide residues

The possibility to perform gas chromatographic analysis using both a mass detector and a selective nitrogen-phosphorous detector will enable highly sensitive analytical results and an optimal identification reliability. In this work we describe an easily workable technical solution, which has been accomplished in our laboratory and the application of the above system to analytical procedures for the detection and determination of nitrogenous herbicides in drinking water and phosphorylated pesticides in agricultural products is discussed.     

Synthesis ofS-(+)-hydroprene

A novel path toS-(+)-hydroprene (1) starting from the technical gradeS-(+)-dihydromyrcene (2, e.e. 50%) is proposed. The latter was selectively transformed intoS-3,7-dimethyloctanal (5) in three steps including hydroalumination. The reactions of5 with allyl- or methallylmagnesium chloride followed, respectively, either by oxygenation in the presence of PdCl₂/CuCl or by ozonolysis, affordS,E-6,10-dimethyl-3-undecen-2-one (7) which was treated with ethoxyethynylmagnesium bromide to give the title juvenile hormone analogue in 23% overall yield.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No 1, pp. 110–112, January, 1993.     

Electron kinetics of collision dominated r.f. bulk plasma in CO: The role of second-kind collisions

Electron energy distribution functions (EEDF) and related properties in the bulk region of the rf CO plasma at the reduced rf field frequency /p₀=×10⁷ sec^–1 torr^–1 have been calculated by solving the time-dependent spatially homogeneous Boltzmann equation in the presence of second-kind collisions and have been interpreted on a microphysical basis. The results show that second-kind collisions (vibrational and electronic) strongly affect the temporal evolution of EEDF, of the mean energy, and of the mean collision frequencies for vibrational and electronic excitation processes, as well as for ionization. In particular, second-kind collisions in the CO rf bulk plasma strongly decrease the modulation of the mean ionization frequency during its periodical alteration in the rf field. Furthermore, the effect of second-kind collisions on an approximate determination of the time-averaged EEDF in the rf bulk plasma using the so-called effective-field appriximation has been estimated.     

一类2(1H)-喹喔啉衍生物的电子轰击质谱分析

以邻苯二胺为原料合成表征了一类喹喔啉衍生物；1-烷基-3-甲基-2（1H）-喹喔啉-2-酮（1-alkyl-3-methly-2(1H)-quinoxalin-2-one，简称AMQ，其中alky=H、CH3、Et、n-C3H5、n-C5H11、n-C16H33)。用电子轰击电离质谱（EI-MS）和核磁共振谱图（^1H-NMR)鉴定了AMQ，研究了不同取代基对这类化合物EI-MS谱图的影响，分析得到一些裂解规律。结果表明：所有样品谱图中均有芳香化合物的特征CnHn^ 系列峰m/z78，65，52，39和（或）m/z77、76、64、63、51、50、38、37。对于末取代的样品及低级烷烃取代的样品，谱图中的基峰为分子离子峰，对于取代基中碳数大于等于3的样品。谱图中的基峰不是分子离子峰，分子离子峰强度随着碳数的增加而降低。这些样品一般容易发生骨架重排，丢失一分子CO，生成1-烷基-2-甲基苯并哒唑正离子。此外，还讨论了谱图中其它的一些碎片离子峰。这对于研究和指导喹喔啉衍生物 的合成，探讨它们在药效及结构特征与生理活性的关系等方面具有重要的应用价值和理论意义。