Plant polysaccharides. IX. Isolation and anticoagulant activity of the polysaccharides ofLagochilus usunachmaticus

A polysaccharide possessing pronounced direct-action anticoagulant activity has been isolated from the epigeal part ofLagochilus usunachmaticus.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 40 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 690–692, September–October, 1997.     

Heterocyclization of compounds containing diazo and cyano groups. 3. Two pathways in the cyclization of 2-diazo-2-cyanoacetic acid derivatives under the influence of bases

1,2,3-Triazol-5-olates are formed in the reaction of diazomalonodiamide and 2-diazo-2-cyanoacetic acid amide and N-methylamide with sodium ethoxide, triethylamine, and ammonia. The products of the reaction of 2-diazo-2-cyanoacetamide with primary amines are mixtures of 4-cyano-1,2,3-triazol-5-olates and 5-amino-1-alkyl-1,2,3-triazole-4-carboxamides.See [1] for communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 926–931, July, 1986.     

Isomerization of 3-aryl-4-sulfolenes and their reaction with some nucleophilic reagents

Bases convert 3-(4-substituted phenyl)-4-sulfolenes to 3-aryl-3-sulfolenes, which are subsequently isomerized to 3-aryl-2-sulfolenes. The ratios of the products depend on the character of the substituent in the phenyl ring, and electron-acceptor substituents accelerate the isomerization.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1072–1077, August, 1975.     

Validation of a screening method for corticosteroids in doping analysis by liquid chromatography/tandem mass spectrometry

A selective and sensitive method for the screening of nine corticosteroids in human urine has been validated. Analyses were performed using an ion trap instrument equipped with an electrospray ionisation (ESI) interface. All corticosteroids were separated in less than 20 min after liquid/liquid extraction with diethyl ether. The limit of detection for all substances was 4 ng/mL or lower. The method was applied to detect betamethasone after the intramuscular injection of Diprophos. Betamethasone could be detected for up to 12 days after administration. Validation of the chromatographic separation and mass spectrometric identification of mixtures of betamethasone and dexamethasone are also presented.     

Tetrazoles: L. Microwave-activated alkylation of 5-aryltetrazoles and 1-substituted tetrazole-5-thiones with 1,3-dibromo-2,2-bis(bromomethyl)propane

Alkylation of 5-aryltetrazoles and 1-substituted tetrazole-5-thiones with 1,3-dibromo-2,2-bis(bromomethyl)propane in dimethylformamide in the presence of sodium hydroxide leads to the formation of tetrakis(5-aryltetrazol-2-ylmethyl)methanes and tetrakis(1-R-tetrazol-5-ylsulfanylmethyl)methanes, respectively. Microwave activation considerably shortens the reaction time and increases the yield.     

Second-order nonlinear optical properties of the Ag(111)/electrolyte interface in the presence of self-assembled monolayers containing conjugated pi systems. I. Alpha-functionalized terthiophene films on Ag(111)

The nonlinear optical properties of self-assembled monolayers obtained from bonding two different alpha-functionalized terthiophenes (alpha-T3) to (111) silver electrode surfaces have been investigated using second harmonic generation (SHG). The two (alpha-T3) compounds used were functionalized with alkane chains of different lengths (C8 and C4), and each was terminated with a thiol anchoring group. A nitrile group was attached to the terminal thiophene ring of the (alpha-T3) compound with the C4 chain. The orientation of the polarization of the incident beam was changed systematically and gradually between "p" and "s" orientation and the SH signal (isotropic and anisotropic contributions) analyzed in both directions ("P" and "S"). The symmetry of the system was reduced by the presence of the adlayers from C3v to C3. The dependence on the applied potential and the incident wavelength has also been studied. The relative magnitudes and phases of the various second-order tensor elements have been estimated and compared with the values for a bare surface. A resonance process in the (alpha-T3) pi moiety has been investigated, and from this, the effective "band-gap" energies of the organic semiconductor SAMs (i.e., the energy difference between the pi-pi bands) have been estimated.     

Synthesis and Structure of Cytisinyl(β-chloro-β-phenylvinyl)phosphinic Esters

2-Propynyl, ethyl, and isopropyl cytisinyl(β-chloro-β-phenylvinyl)phosphinates were synthesized, and their structure was determined by X-ray analysis.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 6, 2005, pp. 917–919.Original Russian Text Copyright © 2005 by Zhivotova, Gazaliev, Fazylov, Karimova, D. Turdybekov, K. Turdybekov.     

Structural aspect of the adduct formation mechanism of metal β-diketonate complexes with macrocyclic polyethers. The structure of the intermediate—The 1:1 guest-host complex of calcium nitrate with 18-crown-6

We compare the structures of intermediate and final products in adduct formation of metal β-diketonate complexes with macrocyclic polyethers using [Ca(NO₃)₂(18C6)] (I) and [Ca(HFA)₂(18C6)] (II), where 18C6 is 18-crown-6 and HFA is hexafluoroacetylacetone. Adduct formation occurs by replacement of nitrate groups in I by HFA ligands with preservation of the coordination number of calcium and the conformation of the macrocycle but with variation in the coordination polyhedron of calcium. Both structures have the same packing mode: the centers of the complexes (Ca atoms) are located in the nodes of planar nets (Shlafly symbol 4⁴) forming two stories parallel to the shortest translations of the monoclinic cell in the same space group C2/c. Because of great size and nonisometricity of HFA ligands as compared to the nitrate group, the planar nets in (II) are well separated, and the tetragons are substantially distorted as compared to those in (I). This structural mechanism of adduct formation is supposed to be true for other complex-forming metals and β-diketonate ligands. X-ray structural analysis and interpretation of results. Synthesis of single crystals. Instute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 3, pp. 56–66, May–June, 1994. Translated by T. Yudanova     

Crystal structure of 2-nitropyridine

The crystal structure of 2-nitropyridine has been determined by x-ray diffraction analysis. The influence of the nitro group on the geometric parameters of the molecule was evaluated, as well as its influence on the molecular parameters of other nitropyridines, depending on the position of this group in the pyridine ring. Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090. E-mail: gatilov@nioch.nsc.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1367–1371, October, 1998.