Mass-spectrometric study of the sesquiterpene lactone grossmisin and its derivatives

Summary The dissociative ionization of grossmisin [O–D]grossmisin, and two of its derivatives have been studied. The appearance of the main fragments in the mass spectrum of grossmisin is due to the elimination by the M⁺ ion of H₂O and CO molecules and CH₃ and OH radicals in various sequences. The hypothesis has been put forward that in the splitting off of a CH₃COOH molecule by the M^+° ion of acetylgrossmisin a rearrangement of the lactone ring takes place with its reclosure at the C₆ carbon atom of the seven-membered ring.M. V. Lomonosov Moscow State University. Patrice Lumumba International Friendship University, Moscow. All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 344–349, May–June, 1977.     

Gas phase electron diffraction study of the hafnium perchlorate molecule

The structure of the Hf(ClO₄)₄ molecule was investigated by electron diffractometry in the gas phase. The model with D₄ symmetry is in best agreement with experimental data; it contains ClO₄ fragments in the form of distorted tetrahedra bridged by two oxygen atoms to the central Hf atom. Ivanovo Chemical Technological Academy. Moscow State University, Chemical Faculty. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 3, pp. 487–493, May-June, 1996.     

Hydrogenation of carbon monoxide over technetium catalysts

Supported Tc catalysts are active in CO hydrogenation, their activity depending on the nature of the support. The reaction proceeds predominantly toward methane formation. All catalysts studied yielded very little C₂ and C₃ hydrocarbons. The thermal desorption data indicate that the CO strongly bound to the substrate is responsible for CH₄ formation.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1507–1511, July, 1992.     

Reaction of substituted 7-cyclopropyl-1,4-benzodioxanes with dinitrogen tetraoxide

The reaction of 6-bromo-7-cyclopropyl-1,4-benzodioxane with N₂O₄ in methylene chloride does not affect the cyclopropane ring and forms the nitrodebrominated product (ipso-substitution). The same reaction of 6-nitro- and 5,6-dinitro-7-cyclopropyl-1,4-benzodioxanes produces only the products with an modified threemembered ring. The difference in the reaction paths of the studied cyclopropylbenzodioxanes with N₂O₄ is explained by the different ratio of substrate to one-electron oxidant, the nitrosyl cation.M. V. Lomonosov Moscow State University, Moscow 119899Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 324–329, March, 1999.     

Lactones ofFerula gigantea

The following substances have been isolated from an acetone extract ofFerula gigantea B. Fedtsch.: a coumarin — umbelliferone, C₉H₆O₂, mp 230–233°C; and sesquiterpene lactones — talassin A, C₂₅H₃₀O₇, mp 188–191°C; malaphyllinin, C₂₄H₂₄O₇, mp 231–235°C; malaphyll, C₂₉H₃₂O₉, mp 212–213°C; and malaphyllin, C₂₆H₂₈O₉, mp 216–218°C. Structures have been proposed for three new sesquiterpene lactones on the basis of an analysis of their spectral characteristics.All-Union Scientific-Research Institute of Medicinal Plants, Moscow. M. V. Lomonosov Moscow State University, Botanical Garden, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 490–495, July–August, 1979.     

Synthesis of trifluoromethyl derivatives of pyrazolidine- and 2-pyrazoline-1-carboxamides and pyrazolidine- and 1-pyrazoline-carbothioamides

The reactions of enones containing trifluoromethyl groups with semicarbazide in basic media proceed unequivocally to give pyrazolidine-1-carboxamides. The direction of the reactions of these enones with thiosemicarbazide depends on their structure; the reaction products are pyrazolidine- and 2-pyrazoline-1-carbothioamides. An enone containing a CF₃ group and an ethoxy group capable of replacement reacts with semicarbazide to give 2-pyrazoline-1-carboxamide and with thiosemicarbazide to give the double addition product, 5-(1-thiosemicarbazido)-2-pyrazoline-1-carbothiamide.M. V. Lomonosov Moscow State University, 119899 Moscow, Russia, N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 117907 Moscow, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 634–644, May, 1998.     

Synthesis of asymmetric secondary phosphines by the cross coupling of arylhalides with silylphosphines

The cross coupling of aryl halides with alkyl(trimethylsilyl)phosphines catalyzed by zero-valent palladium complexes yields secondary alkylarylphosphoranes containing both electron-donor and electron-withdrawing substituents in the aromatic ring. The reversible disproportionation of alkylsilylphosphines to give AlkPH₂ and AlkP(SiMe₃)₂ was observed for the first time during this reaction. This disproportionation does not affect the yield of AlkArPH, which are formed in virtually quantitative yield, due to the high rate of cross coupling with AlkP(SiMe₃)H₂ and the reversibility of the disproportionation process.M. V. Lomonosov Moscow State University, 119899 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1645–1648, July, 1992.     

Synthesis of N(1)-substituted 5-amino-3-methylpyrazoles

With the aim of preparing new biologically active compounds a series of N₍₁₎-substituted 5-amino-3-methylpyrazoles has been obtained from -aminocrotononitrile and mono-substituted hydrazines.K. A. Timiryazev Moscow Agricultural Academy, Moscow 127550, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, 342–344, March, 2000.     

Determination of immobilized digitonin with the aid of an anthrone reagent

A colorimetric method using an anthrone reagent has been developed for the direct quantitative determination of digitonin oxidized with NaIO₄ in solution and after immobilization on Aminosilochrome. The amounts of immobilized digitonin found agree with the results obtained by the sorption of cholesterol from blood serum.M. V. Lomonosov Moscow State University. N. I. Pirogov Second Moscow State Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 453–457, July–August, 1981. Original article submitted January 14, 1981.     

Synthesis, structure, spectral, and electrochemical properties of the Au(I) complex with 5-methoxy-8-(N-picrylamino)quinoline

The synthesis of a gold(I) chelate complex obtained from an autocomplex of the picryl series with a quinoline-containing donor fragment is described. The crystal structure was established by X-ray analysis, the spectral and electrochemical properties were studied. The molecules of the complex obtained have a conformation in which both o-NO₂ groups of the picryl fragment participate in intramolecular charge transfer by contact.M. V. Lomonosov Moscow State University, Moscow 119899, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1028–1035, August, 1999.     

15N NMR spectral parameters of compounds of the N-methylpyrazole series

The¹⁵N NMR chemical shifts and¹⁵N-¹H SSCCs are presented for substituted N-methylpyrazoles with substituents such as CH₃, NO₂, Br, Cl, NH₂, O=CNH₂, O=CPh, and COOH at the carbon atoms. The¹⁵N chemical shifts of the cyclic atoms of nitrogen and the nitro groups are discussed as well as the geminal and vicinal SSCCs of the ring nitrogen atoms with the hydrogen atoms of the CH and CH₃ fragments.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117334 Moscow. D. I. Mendeleev Chemico-Technological Institute, Moscow, Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2554–2561, November, 1992.     

On the determination of equilibrium geometries and potential functions of simple polyatomic molecules from electron diffraction

The degree to which current electron diffraction (ED) techniques allow reliable determination of equilibrium geometries and potential functions of simple molecular systems is studied. Special attention is paid to the choice of the model potential function in the diffraction analysis. The main calculations were performed using accurate diffraction data on SO₂ and SF₆ available from the literature. Routine electron diffraction data on PbCl₂ and PbBr₂ obtained at Moscow University were also treated and found to be reasonably informative regarding bond stretching anharmonicity. Compelling evidence has been presented that any unfavorable situation in the ED analysis of equilibrium geometries and force fields of molecules can be substantially improved by augmenting scattering observations with reliable inferences from vibrational spectroscopy data. This useful cooperation of techniques is shown to be most powerful in efforts to solve equilibrium geometries and molecular dynamics.In addition, numerical simulation experiments were carried out with CO₂ and SO₂ as samples. It is shown that the high-temperature and hot-molecule techniques of electron diffraction may yield valuable information on anharmonicity.     

Hetarenes with a bridge nitrogen atom. 6. Ambident properties of the oxazolo[3,2-a]pyridinium nucleus in reactions with nucleophiles: Prediction and experiment

We have studied the problem of ambident opening of five-membered and six-membered rings of the heteroaromatic oxazolo[3,2-a]pyridinium cation. A quantum chemical SINDO1 calculation of the energies of isomeric adducts of this cation with nucleophiles predicts preferential formation of the C₉-adduct in the case of OH and SH ions with opening of the oxazole fragment, while for nitrogen-containing nucleophiles (NH₂, NMe₂) attack at the C₍₅₎ atom is also likely with opening of the pyridine fragment. We have experimentally observed that this cation undergoes opening of the five-membered ring in reaction with NaSH, opening of the six-membered ring in reaction with piperidine, and opening of both rings in reaction with ammonia.For communication 5, see [1].M. V. Lomonosov Moscow State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 397–402, March, 1997.     

Complexes of cobalt(2+) chloride with hydrochlorides of N-(1,2,4-triazol-5-yl)- and N-(tetrazol-5-yl)benzamidines

We have synthesized complex compounds of Co(2+) chloride with hydrochlorides of N-(1,2,4-triazol-5-yl)benzamidine and N-(tetrazol-5-yl)benzamidine. According to magnetochemistry and electron spectroscopy data, the ligands are coordinated in a bidentate fashion with the N atom of the amidine group and the N atom of the heterocycle with formation of the tetrahedral chromophore CoN₂Cl₂.Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk. N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2311–2315, October, 1992.     

Stereoselectivity in the reduction of chiral indoles to indolines

The reduction of 2-alkylindoles containing a chiral substituent at the nitrogen atom by sodium cyanoborohydride in an acidic medium at -80°C is accompanied by the formation of indolines with S-configuration of the new chiral site at C(₂). An AMI quantum chemical calculation showed that the major diastereomer has greater thermodynamic stability. However, the high diastereoselectivity of this reduction may be attributed only to the relative stability of the different conformations of the intermediate indoleninium cations leading to different diastereomers.M. V. Lomonosov Moscow State University, 119899 Moscow Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1199–1208, September, 1996. Original article submitted August 30, 1996.     

Profile function modeling for fitting powder diffraction peaks

Powder diffraction patterns can be modeled using profile distributions determined from experimental data. This reduces the number of spectrum model parameters and hence enhances the reliability of the mathematical and physical interpretation. The present paper describes the cubic-spline approximation of the profile function. The calculations of Si and α-Al₂O₃ powder diffraction patterns give better residuals than those obtained by the ML and Pearson type VII approximations, which are widely used in the Rietveld method. M. V. Lomonosov Moscow State University. Translated fromZhurmal Strukturnoi Khimii, Vol. 36, No. 1, pp. 138–143, January–February, 1995. Translated by I. Izvekova     

Investigation of a Co-MgO-ZSM catalyst by temperature-programmed reduction,temperature-programmed desorption,and IR spectroscopy

The 32% Co-3% MgO-ZSM (SiO₂/Al₂O₃=38) system has been studied by means of temperature-programmed reduction, temperature-programmed desorption, and IR spectroscopy. The data from temperature-programmed reduction show that cobalt exists on the surface of the catalyst in the form of Co²⁺, CoO, Co₃O₄, and CoO·MgO solid solutions. Reduction of the sample results in the formation of a very inhomogeneous surface with four groups of sites.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. J. Heyrovsky Institute of Physical Chemistry and Electrochemistry, Czechoslovak Academy of Sciences, Prague. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 55–59, January, 1992.     

Synthesis of 4-trifluoromethyl-7-hydroxycoumarin derivatives. Structure of 3-cyano-4-trifluoromethyl-7-acetoxycoumarin

A method was developed for the production of derivatives of 4-trifluoromethyl-7-hydroxycoumarin with electron-withdrawing groups (CN, CF₃CO) at position 3. The structure of 3-cyano-4-trifluoromethyl-7-acetoxycoumarin was proved by x-ray crystallographic investigation. The effect of the substituents on the geometry of the molecule is discussed.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, 117813 Moscow. Institute of Biochemistry, Academy of Sciences of Armenia, 375044 Erevan. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1371–1375, June, 1992.     

2,3,4,5-Tetrahydropyridine 1-oxides. Synthesis and properties (review)

Published data on the synthesis and transformations of 2,3,4,5-tetrahydropyridine 1-oxides are summarized for the first time, classified, and analyzed.A. N. Kosygin Moscow State Textile Academy, Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 435–481, April, 1998.     

Electrophilic condensation of perfluorocyclobutene with fluoroolefins in presence of antimony pentafluoride

Conclusions Perfluorocyclobutene reacts with fluoroolefins in the presence of SbF₅ to give polyfluoroalkylperfluoro-cyclobutenes. Institute of Heteroorganic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2365–2366, October, 1976.