Synthesis of ammonium salts ofO-substitutedN-nitrohydroxylamines

Ammonium salts ofO-substitutedN-nitrohydroxylamines were synthesized by nitration ofO-substitutedN-benzoyl- orp-nitrobenzoy1hydroxylamines followed by treatment of the reaction products with an alcohol solution of ammonia.Translated fromIzvestiya Akadernii Nauk. Seriya Khimicheskaya, No. 1, pp. 132–134, January, 1996.     

Unexpected transformations ofO-vinylacetophenone oxime in the system ButOK-THF

Transformation ofO-vinylacetophenone oxime in the system Bu^tOK-THF was studied. The reaction at 60–65 °C was shown to afford not the anticipated 2-phenylpyrrole, but, instead, 2,4-diphenylpyrrole (21% yield) and oligomer products (40% yield). The latter have the same elemental composition as the startingO-vinyl oxime but do not contain vinyloxy groups or pyrrole fragments. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 615–617, March, 1997.     

Reaction of Chloro(chlorodimethyl)dimethylsilane with O-Silylurethanes and Nicotinic Hydrazide in the Presence of Hexamethyldisilazane

The reaction of chloro(chlorodimethyl)dimethylsilane and hexamethyldisilazane with O-silylurethanes and nicotinic hydrazide gives rise to products whose structure is determined by the composition, structure, and basicity of intermediate compounds. The reaction allowed synthesis of previously unknown linear and heterocyclic compounds.     

Synthesis and studies of organic nitrates of the heterofunctional series

N-Nicotinoyltris(hydroxymethy)aminomethane trinitrate hydronitrate, an analog ofN-nicotinoylethanolamine nitrate (the active principle of the antianginal drug nicorandil), was prepared byO-nitration of the corresponding triol with concentrated HNO₃. The structure of the reaction product was established by X-ray structural analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2224–2227, December, 1997.     

Preparation ofN-nitrohydroxylamines by direct nitration

The possibilities for stabilization of compounds with the A-B-NO₂ fragment, where A is an atom containing a lone electron pair, were examined. It was shown thatN-methyl-O-2,4-dinitro- and 2,4,6-trinitrophenylhydroxylamines undergo nitration with nitronium tetrafluoroborate or with a mixture of nitric acid and acetic anhydride to give the correspondingN-nitrohydroxylamines in high yields.N-Nitro-2,4-dinitrohydroxylamine that contains no methyl group at the nitrogen atom is unstable and forms a product ofO-alkylation upon reaction with diazomethane.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2276–2278, November, 1995.The work was supported by the International Science Foundation (Grant NGN 000).     

Über Darstellung und Reaktivität von 2,4-Diazabicyclo[3.3.1]nonan-3-onen

The 2-cyclohexenones1 a andd resp. react with urea in HCl/EtOH to give 1-hydroxy-4-methyl-7-phenyl- and 1-hydroxy-2,4-diazabicyclo[3.3.1]nonane-3-ones3a and3d resp., whereas the 2-cyclohexenones1b andc resp. transformed by urea to 1,7-dimethyl- and 1-methyl-4-ureido-2,4-diazabicyclo[3.3.1]nonan-3-ones9b andc resp. In the condensation of isophorone1e with urea a product C₁₃H₂₈N₈O₄ of indisdinct structure was formed, whereas the bicyclus3e could not be isolated.Reaction ofAcOAc with3a yielded the 5-methyl-3-oxo-7-phenyl-2,4-diazabicyclo[3.3.1]non-1-ylacetate (15); on heating of3a with acids decomposition to1a and urea took place. NoWagner-Meerwein-rearrangement was observed. The MS-spectra of3a andd are discussed; NMR- and IR-data are reported.No significant herbicidal, fungicidal or insecticidal activity was found in screening-tests on3a.

     

Destruction ofB-polyfluorosubstitutedo-carboranes into anions ofB-fluorosubstitutednido-7,8-dicarbaundecaborates by the action of ethanolic alkali and amines

The destruction ofB-polyfluorosubstitutedo-carboranes by the action of ethanolic alkali and amines was studied. The destraction of trifluoro-o-carborane was found to occur regioselectively. The nature of the amine was shown to affect the stereochemistry of the destruction of trifluoro-o-carborane. The intermediate of the reaction of tetrafiuoro-o-carborane with diethylamine was detected.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1141–1145, June, 1995.     

Hydrogenation of 2- tert -butylphenol over Ni catalyst

The hydrogenation of 2-tert-butylphenol was studied in regard to possibilities of influencing selectivity, namely the ratio ofcis- andtrans-isomers of 2-tert-butylcyclohexanol in the final reaction mixture. The hydrogenation reactions were carried out using the catalyst Ni/Al₂O₃. During the hydrogenations, a higher content of thecis-isomer was attained, when simultaneously the final reaction mixture contained 2-tert-butylcyclohexanone. The content of this intermediate, which primarily hydrogenated to thecis-isomer, increased with a decreased pressure and after the addition of acetic acid into the reaction mixture.     

Darstellung von Organoquecksilber—Stickstoffverbindungen durch Synproportionierung

The exchange reaction ofR ₂Hg and >N–Hg–N< compounds yielding organomercury—nitrogen compounds may be widely applied, as shown here in the synthesis ofN-phenylmercury-amides,-imides,-heterocycles and-triazenes.

     

Synthesis and stereochemical nonrigidity of isomeric Zn(ii)bis-[N-isopropyloxy(mercapto)naphthaldiminates]

Kinetics and reaction mechanisms governing inversion of the tetrahedral configuration at the metal center in the series ofbis-chelate Zn(II) complexes of 3,2-, 1,2-, and 2,1-oxy(mercapto)naphthaldimines, respectively4–6, have been studied with the use of dynamic¹H NMR spectroscopy. A polytopal rearrangement of the diagonal twist type has been found to be an energetically preferable pathway of the inversion reaction for complexes4 and5 with a ZnN₂O₂ coordination site, whereas the inversion reaction for complexes with a ZnN₂S₂ coordination site occurs by an intramolecular dissociation-recombination pathway that involves cleavage of a Zn-N coordination bond. In the case of complexes6, the inversion reaction is governed mainly by intramolecular degenerate ligand exchange reactions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11. pp. 2261–2265, November, 1995.This work was supported by the Russian Foundation for Basic Research (project No. 93-03-18692) and the International Science Foundation (grant No. RNJ 000).     

Dipole moments and molecular conformations ofO-vinyl- andO-ethylacetoximes in solutions

Dipole moments of the molecules ofO-vinyl- andO-ethylacetoximes in octane and THF were measured at different temperatures. In octane, the equilibrium mixture of stableO-vinylacetoxime conformers consists of forms with different polarity. Polarity of these conformers, which are due to rotation about the C−O and N−O bonds, is mainly determined by the relative position of the lone electron pairs of nitrogen and oxygen atoms. The fraction of the polar conformer increases as temperature increases, as well as on going from octane to THF. Saturation of the vinyl group in theO-vinylacetoxime molecule nearly halves the molecular dipole moment in the nonpolar medium, which radically differentiates this compound from vinyl ethers. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1685–1690, September, 1999.     

Studies on the cracking ofn-hexane over H-ZSM-48

The influence of various reaction parameters such as temperature, WHSV and H₂ ton-C₆ molar ratio onn-hexane cracking at atmospheric pressure over ZSM-48 has been studied. The influence of SiO₂/Al₂O₃ variations and isomorphous substitution by Ga and Fe has also been investigated. A linear relationship between the specific catalytic activity for the cracking ofn-hexane and the concentration of strong acid sites has been found.     

Flavonoid glycosides fromThalictrum squarrosum St. ex Willd. andThalictrum minus L.

Two flavonoid allose diglycosides were found in the terrestrial part ofThalictrum squarrosum St. ex Willd. andT. minus L. (Ranunculaceae). 7,4′-Di-O-β-allopyranosylapigenin was isolated fromT. minus. InT. squarrosum, its monoacetate was also found and characterized as 7-O-(6-O-acetyl-β-allopyranosyl)-4′-O-(β-allopyranosyl)apigenin. The sites of attachment of the carbohydrate residues were determined by HMBC; the location of the acetate group was identified by ROESY. Both substances were isolated from these plants for the first time. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 392–394, February, 1999.     

The effect of anions in the coordination spherè of Mg complexes ofN-acetyldehydrophenylalanyl-(S)-valine on the diastereoselectivity of hydrogenation

Diastereoselective hydrogenation in ethanol over Pd/C ofN-acetyldehydrophenylalanyl-(S)-valine (1) as complexes with Mg salts of strong acids gives predominantlyN-acetyl-(S)-phenylalanyl-(S)-valine (de up to 60%). In the case of complexes of1 with Mg salts of weak acids, the sign of asymmetric induction changes. Data of¹⁹F NMR spectroscopy ofN-acetyldehydro(p-fluorophenylalanyl)-(S)-valine indicate that in the former case, the anion of a strong acid does not enter the coordination sphere of the complex, whereas in the larter case, the anion of the weak acid does. The nature of the solvent also influences the reaction stereoselectivity. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1704–1706, September, 1999.     

Kinetic studies on the aminolysis of someO-aryl oximes in benzene

Pyrrolidinolysis and piperidinolysis ofO-aryl oximes show third order dependence on amine with no uncatalytic route. The effect of temperature on separate routes and overall rate is reported and explained.     

Cetylpyridinium bromide-based oil-in-water microemulsions as a medium for hydrolysis of esters of phosphorus acids in the presence of primary amines

High-resolution ¹H NMR technique with Fourier-transform and pulsed-gradient spin-echo was used to study the structure of oil-in-water microemulsions based on cetylpyridinium bromide. The sizes of microdrops and the distribution of components between the disperse and continuous phases were found. It was shown for the hydrolytic decomposition of O,O-bis-(p-nitrophenyl) methyl phosphonate in the presence of amines that the microemulsion medium can affect both the rate and mechanism of hydrolysis. The reaction rate constants depend on the structure of microdrops.     

Rapid hydrogen peroxide release in cell suspensions ofCapsicum spp. elicited by fungal preparations

The release of H₂O₂ by plant cell suspensions elicited with crude hyphal wall preparations has been studied in a complex of plant genotypes (two cvs ofCapsicum annuum and one of C.frutescens) and fungus species(Phytophthora capsici, Ph. parasitica andVerticillium dahliae), representing several combinations of compatibility and both host and nonhost resistance. Production of H₂O₂ was revealed as peroxidasedependent and catalase-inhibited fluorescence quenching of an extracellular probe (Pyranine). All the plant genotypes responded to at least one elicitor, but the cell sensitivity showed a great age-dependent variability. Riboflavine and Mn²⁺ added in the incubation medium acted to some extent as primers for activated cell response, as well as a high Na⁺ concentration. Cell rest condition, however, was not removed. Some quantitative features of responsive plant/elicitor combinations (dose-response relation and lasting time) have been recorded. The complex PO/H₂O₂ of elicited cells could perform detectable lignin-like polymerization of an exogenous natural substrate (coniferyl alcohol). The time-course of pyranine oxidation and lignin-like polymer formation could be recorded by adopting a fluorimetric procedure that allowed sequential observations on the same cell sample. In one instance, the cell reaction seemed associated with thein planta host/parasite incompatibility.     

Phosphorylation ofN-trimethylsilyllactams

Treatment ofN-trimethylsilyllactams with phosphoryl chlorides results in mixtures of products, whose formation can be explained by competition betweenN- andO-phosphorylation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1644–1648, September, 1994.     

Strukturelle Abwandlungen anN-Acetylneuraminsäure, 4. Mitt. Transformationen am Diethyl-dithioketal desN-Acetylneuraminsäure-γ-lactons

Partial protection of diethyldithioketal ofN-acetylneuraminic acid--lactone using one or two equivalents oft-butyldimethylchlorosilane leads to the 9-O-silyletherderivative7 and the 8,9-bis-O-silylderivative5, resp. The reaction of1 as well as7 with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane (TIPSiCl₂) yields selectively the protected products4 and9. The 9,8,7,6-tetra-O-acetyl-N-acetylneuraminic acid--lactone derivative3 is formed by the oxidative desulfurazation of the peracteylated form of1 (i. e.2) by means ofNBS. By reaction of5 withTPPDEAD the 6,7-carbonato compound6 arises instead of the expected 6,7-epoxyderivative. The analogous carbonate8 is formed by treating7 with bisimidazolylcarbonate.

     

Preparation ofN-nitrohydroxylamines by substitutive nitration

Interaction of Na- or K-salts ofN-acetyl-N-methylhydroxylamines with aryl or aryl halides results in correspondingO-substitutedN-acetyl-N-methylhydroxylamines. Nitration of these compounds by nitronium salts or dinitrogen pentoxide results inO-substitutedN-methyl-N-nitrohydroxylamines.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 239–241, January, 1996.