Reactions of 1,2,4-Triazines with Nucleophiles. 6. Use of SNH Methodology for the Direct Introduction of Cyclic Diketone Residue into the 1,2,4-Triazine Ring FORENAME = D. N.

3-R-6-Phenyl-1,2,4-triazine 4-oxides react with cyclic h00173701q230175/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-diketones (dimethylbarbituric acid, dimedone, and indan) in both acidic (substrate activation) and basic conditions (nucleophile activation) with formation of h00173701q230175/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">^H-adducts, intermediates in the nucleophilic substitution of hydrogen (S_N ^H) in 3-R-5-Nu-4-hydroxy-6-phenyl-4,5-dihydro-1,2,4-triazines. Oxidative aromatisation of these intermediates or auto-aromatisation of acylated (benzoyl chloride) at the NOH h00173701q230175/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">-adducts with elimination of benzoic acid gave the corresponding substituted 1,2,4-triazine 4-oxides or 1,2,4-triazines.     

The complexation of 2,3-anthracenedicarboxylate by β- and γ-cyclodextrins in mixed solvent systems as studied by induced circular dichroism. The role of cosolvent hydrophobicity

The complexation of 2,3-anthracenedicarboxylate (ADC) byh523l5155502l8j2/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">- andh523l5155502l8j2/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-cyclodextrins in water containing an organic solvent has been studied by induced circular dichroism. It has been shown that an increase of organic solvent ratio causes the degradation of the 1:1 ADC:h523l5155502l8j2/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-CD complex and the liberation of one guest molecule from the 2:1 ADC:h523l5155502l8j2/xxlarge947.gif" alt="gamma" align="MIDDLE" BORDER="0">-CD complex in water. The higher the hydrophobicity of the cosolvent, the weaker the complexation of ADC byh523l5155502l8j2/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-CD.     

2-氨基-3-氰基-4-(4-氟苯基)-4H-苯并[h]苯并吡喃的合成和晶体结构

标题化合物与N,N-二甲基甲酰胺(DMF)形成的1:1混合结晶物C20H23FN2OC3H7NO由对氟苯甲醛、丙二腈、-萘酚在六氢吡啶存在下合成并经DMF与水的混合溶剂重结晶而得, 其结构通过元素分析、IR 和1H NMR对化合物进行了表征,用X-射线单晶衍射法测定了该化合物的晶体结构。结果表明,晶体属于单斜晶系,P21/n空间群,a = 6.365(1), b = 10.620(2), c = 29.122(6) ? b = 92.00(1), V = 1967.3(6) ?, Mr = 389.42, Z = 4, Dc = 1.315 g/cm3, m (MoKa) = 0.092 mm-1, F(000) = 816。晶体结构用直接法解出,经全矩阵最小二乘法修正,最终偏离因子R = 0.047, wR = 0.1053。化合物分子中,原子C(1), C(2), C(3), C(4), C(5) 和O(1)形成1个六员环,该六员环中C(1)C(2)键长为1.346(3) 牛砻魑肆被肺焦瓜蟆?     

A thermodynamic and structural study of the interactions of pyridino- and diketopyridino-18-crown-6 ligands with some primary organic ammonium cations

Equilibrium constant (K), enthalpy change (h0731n9365160315/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">H), and entropy change (h0731n9365160315/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">S) values have been determined calorimetrically at 25°C in 90%MeOH 10%H₂O (v/v) for the interactions of pyridino-18-crown-6 (P18C6) and diketopyridino-18-crown-6 (K₂P18C6) with perchlorate salts of ammonium, benzylammonium,h0731n9365160315/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-phenylethylammonium,h0731n9365160315/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-phenylethylammonium, andh0731n9365160315/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-(1-naphthyl)ethyl-ammonium cations. The crystal structure of the complex of P18C6 with benzylammonium perchlorate was determined by X-ray crystallography. The¹H 1D and 2D NMR spectra of some of these complexes were used to elucidate their structural features in solution. The logK values for the interaction of the ammonium cations with P18C6 are larger than those with K₂P18C6, probably due to the higher degree of structural flexibility of P18C6. Ligand K₂P18C6 displays appreciable h0731n9365160315/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-h0731n9365160315/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0"> interaction with theh0731n9365160315/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-(1-naphthyl)ethylammonium cation, but not with theh0731n9365160315/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-phenylethylammonium cation.h0731n9365160315/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-h0731n9365160315/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0"> interaction between ligand and cationSupplementary Data relating to this article are deposited with the British Library as Supplementary Publication No SUP 00000 (22 pages)     

Quantum-chemical study of manifestations of conjugation in molecules containing conjugated C=C and C=O bonds

Based on the MNDO calculations of the electronic structure of the molecules of acrolein, glyoxal, and butadiene, possible mechanisms of the conjugation in systems containing conjugated C=C and C=O bonds have been analyzed. In the electronic ground state ofs-trans-acrolein, the h3221t/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">, h3221t/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-conjugation is very small, whereas in the first excited electronic state, the conjugation is substantial, In the ground state ofs-trans-glyoxal, the h3221t/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">,h3221t/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-conjugation should manifest itself clearly but should be weaker than in butadiene, whereas in the first excited electronic state, this conjugation should be more pronounced, Alternation of double and single bonds in the classic structural formula of a molecule does not ensure that this molecule exhibits the properties of a h3221t/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">-conjugated system even in planar conformations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1648–1652, July, 1996.     

Development of a competitive liposome-based lateral flow assay for the rapid detection of the allergenic peanut protein Ara h1

A competitive lateral flow assay for detecting the major peanut allergen, Ara h1, has been developed. The detector reagents are Ara h1-tagged liposomes, and the capture reagents are anti-Ara h1 polyclonal antibodies. Two types of rabbit polyclonal antibodies were raised either against the entire Ara h1 molecules (anti-Ara h1 Ab) or against an immunodominant epitope on Ara h1 (anti-peptide Ab). All of them reacted specifically with Ara h1 in Western Blot against crude peanut proteins. Moreover, the anti-Ara h1 Ab was chosen for this assay development because of its highest immunoactivity to Ara h1-tagged liposomes in the lateral flow assay. The calculated limit of detection (LOD) of this assay is 0.45 g mL^–1 of Ara h1 with a dynamic range between 0.1 and 10 g mL^–1 of Ara h1 in buffer. Additionally, the visually determined detection range is from 1 to 10 g mL^–1 of Ara h1 in buffer. Results using this assay can be obtained within 30 min without the need of sophisticated equipment or techniques; therefore, this lateral flow assay has the potential to be a cost-effective, fast, simple, and sensitive method for on-site screening of peanut allergens.     

About a minimax theorem of Matthies,Strang and Christiansen

We give a new minisup theorem for noncompact strategy sets. Our result is of the type of the Matthies-Strang-Christiansen minimax theorem where the hyperplane should be replaced by any closed convex set. As an application, we derive a slight generalization of the Matthies-Strang-Christiansen minimax theorem.     

Adsorptive stripping voltammetric determination of traces of molybdenum in natural water in the presence ofα-benzoinoxime

The electrochemical behavior of the molybdenum complex of h86463700nl3804h/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-benzoinoxime was investigated using cyclic voltammetry and linear scan voltammetry, after adsorptive accumulation of the complex onto a hanging mercury drop electrode (HMDE). The signal corresponds to the reduction of molybdenum in the complex adsorbed at the HMDE surface. Under optimal conditions, the adsorptive stripping voltammetric procedure gave an extremely low detection limit of 0.1 nM (9.6ng/l) Mo(VI) following stirred accumulation for 5 min at 0.0 V (vs. Ag/AgCl). The reduction cur rent-[Mo(VI)] relationships were linear up to 25 and 100 nM. Repetitive determinations of 10 nM solutions gave relative standard deviations of 2.2 and 3.5%, for 1 and 5-min accumulation periods, respectively. Most of the ions investigated did not interfere with the determination of molybdenum, except for tungsten. Excellent selectivity against copper was observed. The proposed procedure was applied to the direct determination of molybdenum in natural water.     

Inter-ring η6⇌η5 haptotropic rearrangements of 18ē and 19ē (η5-pentamethylcyclopentadienyl)(η6-9-methylfluorenyl)iron complexes

New cationic complexes [(h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁶-C₁₃H₁₀)Fe(h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁵-Cp^*)]PF₆ and [(h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁶-9-CH₃-C₁₃H₉)Fe(h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁵-Cp^*)]PF₆ were obtained by the reaction of Cp^*Fe(CO)₂Br with fluorene and 9-methylfluorene, respectively. Deprotonation of these complexes byt-BuOK in THF affords zwitter-ionic compounds (h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁶-C₁₃H₉)Fe(h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁵-Cp^*) and (h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁶-9-CH₃-C₁₃H₈)Fe(h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁵-Cp^*) (A). WhenA is heated in nonane at 150 °C it undergoes h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁶h217p6414k4439vn/xxlarge8652.gif" alt="rlhar" align="MIDDLE" BORDER="0">h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁵ inter-ring rearrangement with the formation of hexamethyldibenzoferrocene (B). The electrochemical behavior ofA andB was studied by cyclic voltammetry. One-electron reduction ofA andB to the corresponding radical anions induces inter-ring haptotropic rearrangementA ^.–h217p6414k4439vn/xxlarge8652.gif" alt="rlhar" align="MIDDLE" BORDER="0">h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">B ^.–. The equilibrium in the 19h217p6414k4439vn/xxlarge275.gif" alt="emacr" align="BASELINE" BORDER="0"> state is shifted to the h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁶-isomeric radical anionA ^.–, while in the 18h217p6414k4439vn/xxlarge275.gif" alt="emacr" align="BASELINE" BORDER="0"> precursors, it shifts to the h217p6414k4439vn/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0">⁵-isomerB.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 319–324, February, 1994.The authors are grateful to D. V. Zagorevskii (A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences) for recording and interpreting the mass spectra, and to A. A. Borisenko (Moscow State University) for recording the NMR spectra.This work was financially supported by the Russian Foundation for Basic Research (Grant 93-03-5209).     

Transformed steroids

A preparative method for 9a-hydroxylation of h556764284k51191/xxlarge916.gif" alt="Delta" align="BASELINE" BORDER="0">⁵-3h556764284k51191/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-hydroxysteroids using the fungi ofCircinella sp. 10Kh-1220 not capable of modifying theA ring has been developed. It is established that the yields of the main and the side products greatly depend on the transformation conditions, mycelium age, and the structure of the steroid substrate. Under the optimal transformation conditions novel 9h556764284k51191/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-hydroxysubstituted derivatives of androstenolone, pregnenolone, 16-dehydro-16h556764284k51191/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">,17h556764284k51191/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-epoxy-, and-16h556764284k51191/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-methoxypregnenolone have been obtained in 36–80 % yields.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 737–743, April, 1994.