Thermodynamic study of the system cadmium - zinc,cadmium - lead,cadmium - tin,bismuth - cadmium,tin - zinc,and lead - tin

Russian Chemical Bulletin -     

Synthesis of 4-, 5-, 6-, and 7-azidotryptamines

Synthesis of azidotryptamines from commercially available nitroindoles via the corresponding amino tryptamines in good overall yields (15-38%) is presented.     

Deformed phthalocyanines: synthesis and characterization of zinc phthalocyanines bearing phenyl substituents at the 1-, 4-, 8-, 11-, 15-, 18-, 22-, and/or 25-positions

The synthesis of a series of zinc phthalocyanines partially phenyl-substituted at the 1-, 4-, 8-, 11-, 15-, 18-, 22-, and/or 25-positions (the so-called alpha-positions) is reported. Macrocycle formation based on 3,6-diphenylphthalonitrile, o-phthalonitrile, and zinc acetate predominantly yielded the near-planar disubstituted complex and opposite tetrasubstituted isomer, while the lithium method yielded the sterically hindered hexasubstituted complex and adjacent tetrasubstituted isomer. All compounds have been characterized by 1H NMR, MALDI-TOF-MS, and elemental analysis methods. In addition, crystal structures have been solved for the di-, hexa-, and octasubstituted complexes and the adjacent tetrasubstituted isomer. DFT geometry optimization calculations predict more highly deformed structures than those observed in the crystals. The packing force of the crystals cannot therefore be ignored, particularly for the less phenyl-substituted derivatives. The crystal structures have revealed that overlap of the phenyl groups causes substantial deformation of the phthalocyanine (Pc) ligands within the crystals, while strong pi-pi stacking in the remainder of the Pc moiety lacking phenyl substituents can suppress the impact of the deformation. Absorption spectra show sizable red shifts of the Q-band with increasing number of phenyl groups. Analysis of the results of absorption spectra and electrochemical measurements reveals that a substantial portion of the red shift is attributable to the ring deformations. Molecular orbital calculations lend further support to this conclusion. A moderately intense absorption band emerging at around 430 nm for highly deformed octaphenyl-substituted zinc Pc can be assigned to the HOMO-->LUMO+3 transition, which is parity-forbidden for planar Pcs, but becomes allowed since the ring deformations remove the center of symmetry.     

First comprehensive bakkane approach: stereoselective and efficient dichloroketene-based total syntheses of (+/-)- and (-)-9-acetoxyfukinanolide, (+/-)- and (+)-bakkenolide A, (-)-bakkenolides III,B, C,H, L,V, and X, (+/-)- and (-)-homogynolide A, (+/-)-homogynolide B,and (+/-)-palmosalide C

Cycloaddition of dichloroketene with dimethylcyclohexenes has been used as the key reaction in an efficient, general approach to the bakkanes. New methods and methodologies that have been developed in this work include spiro beta-methylene-gamma-butyrolactonizations, a vicinal dicarboxylation, an angelic ester preparation, a transesterification, an epoxy ketone double reduction, and a retro aldol-aldol approach to low-energy aldol isomers.     

2-芳氧基-5-苯基-1,3,4-噁二唑类化合物的合成

本文通过芳氧基负离子在2—甲磺酰基—苯基—1,3,4—噁二唑环2—位上的亲核取代反应制得9个新的2—芳氧基—5—苯基—l,3,4—噁二唑衍生物。所有化合物的结构经元素分析,IR,~1H NMR和MS确认。初步抗菌实验表明这些化合物具有一定的抑制枯草芽孢杆菌繁殖的活性。 2,5—二取代l,3,4—噁二唑衍生物具有广泛的生物活性,如抗菌,抗黄球菌,除草杀棉花牙虫等。Madhavan等曾通过芳胺在2— 甲磺酰基—5—芳基1,3,4—噁二唑环上的亲核取代反应,制得了2—芳氨基—5—芳基—l,3,4—噁二唑衍生物,我们也曾通过酰肼等亲核试剂在2—甲磺酰基—5—(3,4,5—三甲氧基苯基)—1,3,4—噁二唑环上的亲核取代反应,得到了2—取代酰肼基—5—(3,4,5—三甲氧基苯基)—l,3,4—噁二唑衍生物。在此基础上,我们拟通过Aro在2—甲磺酰基     

Syntheses of 1-, 2-, 3- and 4-acridinecarbaldehydes

The four acridinecarbaldehydes, namely, acridine-1-carbaldehyde, acridine-2-carbaldehyde, acridine-3-carbaldehyde, and acridine-4-carbaldehyde have been synthesized for the first time.     

Huge (14-, 21-, 28-, 35-, 56- and 70-membered ring) macrocyclic lactams--a novel family of carbopeptoid-cyclodextrins

Hydrogenation of linear ω-azido-pentafluorophenyl esters gives cyclic peptides containing 14-, 21-, 28-, 35-, 56- and 70-membered ring lactams from oligomers derived from ε-amino acids in excellent to moderate yields with a lack of racemisation during the cyclisation step.     

2-, 10-, and 2,10-phosphorylated phenothiazines

Russian Chemical Bulletin -     

Conformational behavior of 2-, 2,3-, 2,5-, and 2,3,5-alkyl-substituted 1,3,2-oxazaborinanes

The molecules of 2- and 2,3-substituted 1,3,2-oxazaborinanes exist in a state of interconversion of the heterocycle that is rapid on the NMR time scale; the molecules of 2,5- and 2,3,5-substituted 1,3,2-oxazaborinanes exist primarily in the sofa conformation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1424–1427, October, 1990.     

Aromaticity and antiaromaticity in 4-, 6-, 8-, and 10-membered conjugated hydrocarbon rings

Recently, we presented a molecular orbital (MO) model of aromaticity that explains, in terms of simple orbital-overlap arguments, why benzene (C(6)H(6)) has a regular structure with delocalized double bonds whereas the geometry of 1,3-cyclobutadiene (C(4)H(4)) is distorted with localized double bonds. Here, we show that the same model and the same type of orbital-overlap arguments also account for the irregular and regular structures of 1,3,5,7-cyclooctatetraene (C(8)H(8)) and 1,3,5,7,9-cyclodecapentaene (C(10)H(10)), respectively. Our MO model is based on accurate Kohn-Sham DFT analyses of the bonding in C(4)H(4), C(6)H(6), C(8)H(8), and C(10)H(10) and how the bonding mechanism is affected if these molecules undergo geometrical deformations between regular, delocalized ring structures and distorted ones with localized double bonds. The propensity of the pi electrons is always to localize the double bonds, against the delocalizing force of the sigma electrons. Importantly, we show that the pi electrons nevertheless determine the localization (in C(4)H(4) and C(8)H(8)) or delocalization (in C(6)H(6) and C(10)H(10)) of the double bonds.     

Metal-free inorganic ligands for colloidal nanocrystals: S2-, HS-, Se2-, HSe-, Te2-, HTe-, TeS3(2-), OH-, and NH2- as surface ligands

All-inorganic colloidal nanocrystals were synthesized by replacing organic capping ligands on chemically synthesized nanocrystals with metal-free inorganic ions such as S(2-), HS(-), Se(2-), HSe(-), Te(2-), HTe(-), TeS(3)(2-), OH(-) and NH(2)(-). These simple ligands adhered to the NC surface and provided colloidal stability in polar solvents. The versatility of such ligand exchange has been demonstrated for various semiconductor and metal nanocrystals of different size and shape. We showed that the key aspects of Pearson's hard and soft acids and bases (HSAB) principle, originally developed for metal coordination compounds, can be applied to the bonding of molecular species to the nanocrystal surface. The use of small inorganic ligands instead of traditional ligands with long hydrocarbon tails facilitated the charge transport between individual nanocrystals and opened up interesting opportunities for device integration of colloidal nanostructures.     

1,2,5-, 1,3,4- and 1,2,4-Oxadiazoles

Discrepancies found for some oxygen-containing compounds in a recent VESCF study of dipole moments have been further investigated by studying in detail furan, oxazole, isoxazole, and three isomeric oxadiazoles. In a preliminary geometrical study it was found that the method described previously for estimating ring angles and bond lengths satisfactorily accounted for observed geometries. However in those compounds where more than one ring atom carries lone pair -electrons, the electrostatic forces originating in these lone-pair dipoles have a considerable influence on ring geometry. When this is incorporated in the geometrical treatment, good agreement with known geometries is obtained.The effect of using Burns' rules for orbital exponents rather than Slater's rules to derive lone pair moments and the effect of including lone pair potentials in the hamiltonian have been studied. The best agreement between calculated and observed dipole moments (within 0.2 D) is obtained by using the BJ method that was used in the previous study but with revised values for some of the basic resonance integrals. The revised values are shown to be more in keeping with the relevant bond lengths and atomic numbers than the values previously used.

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Zusammenfassung Die in einer VESCF- (PPP mit Elektronegativitäts-Variation) Untersuchung über Dipolmomente aufgetretenen Abweichungen bei einigen O-haltigen Ringen wurden untersucht. Bei Ringen, die mehrere einsame Elektronenpaare tragen, muß die kürzlich angegebene einfache Methode zur Bestimmung der Geometrie durch zusätzliche Berücksichtigung der elektrostatischen Kräfte zwischen diesen Elektronenpaaren erweitert werden. Die Burnsschen Orbitalexponenten führen bei den einsamen Elektronenpaaren zu besseren Ergebnissen, als die Slaterschen. Die besten Dipolmomente werden mit der sog. BJ-Methode erhalten (Fehler < 0,2 D); allerdings wurden einige Resonanzintegrale gegenüber früheren Rechnungen abgeändert. Diese Resonanzintegrale entsprechen auch besser den Bindungslängen und Kernladungen.

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Résumé On a réétudié les contradictions trouvées pour certains composés oxygénés dans une étude récente des moments dipolaires par la méthode VESCF, en examinant en détail le furane, l'oxazole, l'isoxazole et trois oxadiazoles isomères. La méthode précédemment décrite pour l'estimation des angles du cycle et des longueurs de liaison rend compte de façon satisfaisante des géometries observées. Cependant dans les composés où plus d'un atome du cycle porte des paires libres d'électrons , les forces électrostatiques provenant de ces dipôles ont une influence considérable sur la géométrie du cycle. Lorsque l'on tient compte de cela dans le traitement de la géométrie, un bon accord est obtenu avec l'expérience.On a étudié l'effet provoqué par l'usage des règles de Burns plutôt que celles de Slater pour les exposants orbitaux pour l'obtention des moments des paires libres ainsi que l'effet de l'inclusion des potentiels des paires libres dans l'hamiltonien. Le meilleur accord entre moments dipolaires calculés et observés (á 0,2 D. près) est obtenu en utilisant la méthode BJ utilisée dans l'étude précédente mais avec des valeurs révisées pour certaines intégrales de résonance fondamentales. Ces nouvelles valeurs sont plus consistances avec les longueurs de liaison et les nombres atomiques que celles précédemment utilisées.

     

Reissert compound studies. XXXVI. Observations on 1,7-, 4,6-, 4,7-, and 1,10-phenanthrolines

Reissert compounds have been prepared from 1,7-, 4,6-, and 4,7-phenanthrolines. In the case of 4,7-phenanthroline, both mono- and di-Reissert compounds have been prepared. A number of Reissert analogs have also been prepared in this series. 1,10-Phenanthroline fails to give a Reissert compound.     

1,4,7,10-N,N,N,N.四(2-(4-(2-乙酰硫基乙氧基)苯氧基)乙基)-1,4,7,10-四氮杂环十二烷的合成研究

以对苄氧基苯酚为原料,经3步反应合成不对称的对苯二酚烷氧基化合物,并以此为原料,合成乙酰硫基修饰的cyclen四取代氢醌醚链化合物.该路线不仅反应条件温和,操作易行,且收率高,克服了文献报道的合成路线重复性差、收率低的缺点.关键中间体及目标化合物经~1H NMR、~(13)C NMR、MS、IR和元素分析表征.     

Synthesis,spectroscopic, biological,and theoretical studies of new complexes from (E)-3-(2-(5, 6- diphenyl-1,2,4- triazin-3- yl)hydrazono)butan-2- one oxime

New mononuclear Fe (III), Cu (II), Ag (I), ZrO ( IV) and UO₂(VI) complexes were synthesized by the reaction of metal ions with (E)-3-(2-(5, 6- diphenyl-1,2,4- triazin-3- yl)hydrazono)butan-2- one oxime. The structures of the metal complexes were characterized using analytical, spectral (infrared, electronic, ¹H NMR, electron spin resonance (ESR), and mass), magnetic moment, molar conductance, thermal gravimetric analysis, and powder X-ray diffraction (XRD) measurements. All complexes have octahedral geometries except the Cu (II) complex, which has square planar geometry, and the UO₂(VI) complex, in which the coordination number is seven. The ligand acts as a (neutral, monoanionic or dianionic) tridentate with N₂O coordinating sites: N-azomethine, N-triazine, and O-oxime. Fluorescence spectral studies were carried out in solid state and in dimethylformamide (DMF). The kinetic parameters of the thermal decomposition stages were calculated using Coats–Redfern equations. The morphological structures of the ligand and some complexes were determined using XRD. The molecular orbital calculations were carried out for the ligand and metal complexes using the Hyperchem 7.52 program on the basis of the PM3 level. The antimicrobial activities of the ligand and its complexes were investigated towards the microorganisms S. aureus and B. subtilis as Gram-positive bacteria, S. typhimurium and E. coli as Gram-negative bacteria, C. albicans, and A. fumigatus. The ligand and its complexes showed antitumor activity against Hep G-2 cell lines, where Cu (II) and Ag (I) complexes seem to be promising as they showed IC₅₀ values that are lower than and comparable to that of the antitumor drug doxorubicin.     

Syntheses of 3-, 4-, and 5-O-feruloylquinic acids

The efficient synthesis of 3-, 4-, and 5-O-feruloylquinic acids starting from d-(?)-quinic acid is described. Esterification of suitably protected quinic acid derivatives with 3-(4-acetoxy-3-methoxyphenyl)-acryloyl chloride and subsequent hydrolysis of all the protecting groups afforded the title products in overall yields of 33%, 15%, and 45%, respectively, (from quinic acid).