Investigation of the structure of a melt and molecular dynamics of ortho- and pyrophosphates by Raman spectroscopy

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 4, pp. 535–540, October, 1991.     

Electromechanical properties of Pb<Subscript>3</Subscript>Ga<Subscript>2</Subscript>Ge<Subscript>4</Subscript>O<Subscript>14</Subscript> piezoelectric crystals grown from solution in a melt

Single crystals of lead gallium germanate Pb₃Ga₂Ge₄O₁₄ are grown from their own solution melts. The propagation of bulk acoustic waves is investigated, and the elastic, piezoelectric, and dielectric constants are calculated. The temperature dependences of the dielectric constants of this compound are analyzed.     

Acetylene weak bands at 2.5 μm from intracavity Cr:ZnSe laser absorption observed with time-resolved Fourier transform spectroscopy

The spectral dynamics of a mid-infrared multimode Cr(2+):ZnSe laser located in a vacuum sealed chamber containing acetylene at low pressure is analyzed by a stepping-mode high-resolution time-resolved Fourier transform interferometer. Doppler-limited absorption spectra of C(2)H(2) in natural isotopic abundance are recorded around 4000 cm(-1) with kilometric absorption path lengths and sensitivities better than 3 10(-8) cm(-1). Two cold bands are newly identified and assigned to the ν(1)+ν(4) (1) and ν(3)+ν(5) (1) transitions of (12)C(13)CH(2). The ν(1)+ν(5) (1) band of (12)C(2)HD and fourteen (12)C(2)H(2) bands are observed, among which for the first time ν(2)+2ν(4) (2)+ν(5) (-1).     

Structure and reactivity of 2-methyl-9-hydroxy-4H-pyrido[1,2-a]pyrimidin-4-one

It has been shown that the alkylation of 2-methyl-9-hydroxy-4H-pyrido[1,2-a]pyrimidin-4-one takes place at the oxygen atom, but electrophilic substitution takes place mainly at position 8 of the molecule (the ortho position relative to the hydroxy group).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1660–1666, December, 1992.     

Application of Gas Chromatography and Gas Chromatography–Mass Spectrometry to the Detection of γ-Hydroxybutyric Acid and Its Precursors in Various Materials

Modified procedures were developed for the detection of -hydroxybutyric acid and 1,4-butanediol (its metabolic precursor) in foods, food additives, and urine using gas chromatography and gas chromatography–mass spectrometry. The analytical range was 0.1–20 wt %.     

Synthesis and 13C NMR spectra of 5-alkyl-1,4-diaza- and 5-alkyl-1-aza-4-oxabicyclo [3.3.0]octan-8-ones

A group of previously unreported 5-alkyl-1,4-diaza- and 5-alkyl-1-aza-4-oxabicyclo[3.3.0]octan-8-ones have been synthesized from the ethyl esters of -ketocarboxylic acids and ethylenediamine or ethanolamine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1405–1408, October, 1987.     

Phase equilibria and thermodynamics of coexisting phases in rare-earth element-iron-oxygen systems. II. The praseodymium-iron-oxygen system

The phase equilibria and the thermodynamics of coexisting phases in the PrFeO system have been studied using static and dynamic methods for attaining equilibrium with subsequent annealing and identification of the condensed phases by X-ray analysis. Equilibrium phase diagrams have been constructed to define the changes that take place in the PrFeO system on variation of the partial oxygen pressure, the temperature, and the composition of the initial mixture of oxides. An isothermal cross section at 1300°K and equilibrium diagrams of the type P_O2 = f(composition) with with one composition parameter fixed and T = f(composition) with P_O2 = constant have been constructed. It has been shown in the PrFeO system that only one ternary compound with perovskite structure, PrFeO₃, is formed, and furthermore, it is stable no matter how high the partial oxygen pressure.     

(Z)-3-p-tolylsulfinylacrylonitrile as a chiral dienophile: diels-alder reactions with furan and acyclic dienes

The behavior of (Z)-3-p-tolylsulfinylacrylonitrile (1) as a chiral dienophile has been evaluated from its reactions with furan and acyclic dienes. Electrostatic interactions of the cyano group with the sulfinyl one restrict the conformational mobility around the C-S bond, thus controlling the pi-facial selectivity, which is almost complete in all cases, the approach of the diene from the less-hindered face of the dienophile (that bearing the lone electron pair) in the predominant rotamer being the favored one. The regioselectivity is also completely controlled by the cyano group. Additionally, the reactivity of compound 1 as well as its endo-selectivity are both higher than those observed for the corresponding (Z)-3-sulfinylacrylates, thus proving the potential of sulfinylnitriles as chiral dienophiles.     

Negative ion mass spectra and structure of 4-substituted 1-phenyl-3-methyl-5-pyrazolones

This is the first study of the electron capture dissociative resonance (ECDR) mass spectra of 4-substituted 1-phenyl-3-methyl-5=pyrazolones. The major features of the fragmentation of these compounds under ECDR. conditions were found relative to their substituent properties. After loss of the methyl group from the nitrogen atom, the pyrazolone ring isomerizes to a pyrazole ring with localization of the negative charge on the oxygen atom of the carbonyl group. The intensity of the [M - Ch₃]^– fragment depends on the substituent properties.Communication 5 in the series on the Mass Spectroscopy of Biologically Active Compounds, For Communication 4, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1663–1670, December, 1985.