The synthesis of bis(mercaptomethyl)phosphonic acid

Conclusions The reaction of bis(chloromethyl)phosphonic acid with thiourea gave the hydrochloride of bis(thio-ureylmethyl)phosphonic acid, the alkaline decomposition of which gave bis(mercaptomethyl)phosphonic acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1625–1626, July, 1968.     

Radical arylation of acetyl-substituted thioureas

Conclusions The reaction of N-acetylthiourea with phenyl and p-tolyl radicals leads to diaryl disulfides and 2-methyl -4-thioaryl-6-acetamido-s-triazines.A scheme was proposed for the formation of substituted s-triazines by the successive transformation of the intermediate radicals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2591–2593, November, 1982.     

Shed plane leaves as a source ofα-tocopherol

A natural source of -tocopherol — shed plane leaves — has been found. The dynamics of the accumulation of a-tocopherol over the vegetation period of the plant has been studied, and a method has been developed for its isolation and quantitative determination.Deceased.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 372–374, May–June, 1995. Original article     

Spectrum of a scalar field in a Gödel cosmological model

A study is made of the spectrum of a scalar field for the general case of a causal metric of the Gödel type. Its substantial difference from the spectrum of a noncausal metric is demonstrated. In a causal metric, the spectrum of scalar particles is divided into three regions: 1) a region of low energy and a discrete spectrum; 2) a region of intermediate energy and a continuous spectrum, with the same dispersion relation; 3) a region of high energy and likewise a continuous spectrum, but with a different dispersion relation. In the latter case, the dispersion relation is symmetrical with respect to a sign change of the particle energy , whereas in the first two cases symmetry is conserved only for a simultaneous sign change of both and the projection of the orbital moment onto the z axis. For nonzero mass and a quite low z component of the particle momentum, the upper and lower continua of the states merge, and the energy gap disappears.St. Petersburg University of Economics and Finance. Translated from Izvestiya Vysshikh Zavedenii, Fizika, No.9, pp. 39–43, September, 1993.     

Concentration dependence of the surface tension of ternary systems

A surface tension isotherm equation for ternary systems was derived based on general thermodynamic expressions with consideration for the concentration dependence of the molar surface area. Within the experimental errors, the equation describes the properties of ternary systems with smooth surface tension isotherms.     

Determination of the elemental composition of cyanobacteria cells and cell fractions by atomic emission and atomic absorption spectrometry

An approach to studying the elemental composition of cyanobacteria Spirulina platensis and Nostoc commune using a set of complementary analytical methods (ICP-AES, PAAS, and ETAAS) is proposed. The procedures were adapted for the determination of macro- and microelements (Na, K, Mg, Ca, Fe, Mn, Cu, Mo, Zn, B, and Se) in the biomass of cyanobacteria and separated cell fractions (chloroform and water-methanol extracts and precipitates). The conditions for the mineralization of biological materials were optimized for autoclave and microwave sample preparation procedures. The evaporation and atomization of Se and Mo in a graphite furnace in the presence of chloroform and methanol were studied. The use of combined analytical methods and the interpretation of analytical results allow one to draw conclusions about the ability of cyanobacteria to accumulate biologically important microelements (B, Mo, Se, and Zn) and to optimize technological processes for manufacturing biologically active substances.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 1, 2005, pp. 35–40.Original Russian Text Copyright © 2005 by Sedykh, Lyabusheva, Tambiev, Bannykh.     

The rotational mobility of fulleropyrrolineoxyl in toluene solution

The rotational mobility of a stable fullerene-based nitroxyl radical (fulleropyrrolineoxyl) in toluene was studied. The rotational correlation time of fulleropyrrolineoxyl was found to be about eight times longer than that of 4-oxy-2,2,6,6-tetramethylpiperidine-1-oxyl. The activation energy of the rotational motion of both probes was determined and their hydrodynamic radii estimated.     

Theoretical conformational analysis of some agonists of the H1- and H2-receptors of histamine

The conformational equilibrium of -(aminoethyl)pyridines has been studied by molecular-mechanics using the geometry optimization. It has been determined that the equilibrium is characterized by the nearly statistical distribution of the ap- and sc-conformers about the bond. Substitution of the dimethylamino-group for the amino-group results in a slight shift of the equilibrium toward the ap-rotamers. The global minimum in -(ammoniumethyl)pyridines corresponds to the conformation with the +sc-orientation about the central C-C bond and the -sc-orientation (in the case of the dimethylammonium derivatives) about the bond. In the latter conformation, the bond of the ammonium group is oriented toward the pyridine cycle. For charged compounds, the regular orthogonal conformation of the aromatic-ring plate is distorted (the vicinal C-C bond becomes eclipsed).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1833–1840, August, 1991.The authors are grateful to P. P. Shagidullin and A. Kh. Plyamovatyi for their interest in this work and for fruitful discussions.     

Alkaloids of Liriodendron tulipifera

Tashkent Agricultural Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 587–588, July–August, 1991.     

Inhomogeneous Minkowski conjecture (letter to the editor)

The author corrects errors which occurred in his papers published in J. Sov. Math.,23, No. 2 (1983). A new bound of the inhomogeneous minimum Mn is given: forn?200 $$M_n \leqslant 2^{ - \tfrac{n}{2}} \left( {4.4455 + \tfrac{{1.3545}}{{n - 1}}} \right).$$ This is stronger than Davenport's result forn?200.