Reaction of benzylidene-2-naphthylamine with the ethyl ester of 3-pyridyl-β-oxopropionic acid

The reaction of benzylidene-2-naphthylamine with ethyl -(3-ethyl)--oxopropionate under various conditions gave the ethyl ester of -(2-naphthylamino)benzyl--(3-pyridyl)--oxopropionic acid, 1-(3-pyridyl)-3 phenylbenzo[f]quinoline, ethyl ester of 1-(3-pyridyl)-3-phenylbenzo[f]quinoline-2-carboxylic acid, and N-(2-naphthyl)amide of -(3-pyridyl)--oxopropionic acid. The IR, UV, and mass spectra of the products were studied and the pathways for their formation were discussed.Institute of Physical Organic Chemistry, Belorussian Academy of Sciences, Minsk 220603. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 807–810, June, 1996. Original article submitted December 30, 1995.     

Quantitative electron-probe microanalysis of light elements: Determination ofa-Si∶C∶N∶O∶H insulating films

Amorphous SiCNOH films (1–3 m) are studied by EPMA after deposition of gold (1–5 nm) as a conductive coating. Its influence on thek-ratios (X-ray intensity relative to an uncoated standard) of silicon, carbon, nitrogen and oxygen is described as a linear function of the simultaneously determinedk-ratio of gold. Thek-ratios representing the uncoated specimen are obtained by extrapolation and, in combination with the PAP matrix correction model, quantitative EPMA can be performed with an analytical error of 2–5%, as it is demonstrated by samples of SiC, Si₃N₄ and SiO₂. No systematic shift of the concentrations is observed for layers ofa-SiCNOH determined at various electron energies of 5–12.5 keV. Hydrogen is calculated by difference and the concentrations prove to be a useful estimate in agreement with the results of chemical analysis. Si-K/Si-K spectra recorded on organo-silicon films and binary silicon compounds point out significant differences concerning the formation of Si-C, Si-N and Si-O chemical bonds.     

Triterpene Glycosides of Astragalus and Their Genins. LXI. Occurrence of Cycloartane 6-O-Monodesmosides

Cyclosiversigenin 6-O--L-rhamnopyranoside and 6-O--D-glucopyranoside were isolated fromAstragalus coluteocarpusBoiss. (Leguminosae) andAstragalus dissectusB. Fedtsch. et N. Ivanova, respectively. Cyclosiversigenin 5-O--L-rhamnopyranoside was shown to be an artifact forAstragalus coluteocarpus.Thus, the cyclosiversigenin 6-O--D-glucopyranoside that was isolated from certainAstragalusspecies is hypothesized also to be an artifact. Glycosylation of the 6 -hydroxyl group of cycloartanes by D-glucose and D-xylose, in contrast with other substituents, does not change the low-field position of the PMR signal of the 4-CH ₃ group (1.65 2.01 ppm) that is caused by the influence of deuteropyridine directly on the 6 -hydroxyl. Obviously one of the hydroxyls of the -D-glucopyranoside or -D-xylopyranoside residues has the same effect in this instance.     

Potentiometric investigation of ternary complexes of nickel(II), zinc(II) and cadmium(II) ions with β-alaninehydroxamic acid and ethylenediamine

Summary The formation constants of mixed ligand complexes of M^II (M = Ni, Zn or Cd) with -alaninehydroxamic acid (-Alaha) as primary ligand (A) and ethylenediamine (en) as secondary ligand (B) have been determined potentiometrically [298 K, = 0.2 (KCl)]. The formation constants for binary systems of -alaninehydroxamic acid and ethylenediamine were determined under identical experimental conditions. The pH-titration data were analysed using the SUPERQUAD computer program. The relative stability of each ternary complex was compared to that of its corresponding binary complex in terms of log X values.     

Crystal and Molecular Structure of 5,7,12,14-Tetramethyl-1,4,8,11-tetraaza-4,6,11,13-tetraenatogold(III) Bromide [Au(C14H22N4)]Br

The crystal and molecular structure of [Au(C₁₄H₂₂N₄)]Br has been determined. Monoclinic crystals, a=12.592(2), b=6.309(1), c=19.628(2) ; =98.00(1)°, V=1544.1(4) ³, Z=4, d_calc=2.251 g/cm³, space group C2/c. The structure consists of virtually planar centrosymmetric [Au(C₁₄H₂₂N₄)]⁺ cations and Br^- anions. The coordination sphere of the gold atom involves four nitrogen atoms of the ligands, forming a planar square. The Au–N bond lengths are equal (the mean length is 1.982(7) ). The C–C and C–N bonds inside the -diiminate rings are delocalized. The parameters of the -diiminate rings of the [Au(C₁₄H₂₂N₄)]⁺ cation are compared with the parameters of the related complexes.     

Über die neutralen Sesqui- und Triterpene des Weihrauchs

Zusammenfassung Aus Weihrauch konnte neben den bekannten Säuren 11-Keto--boswellinsäure-acetat isoliert werden. Der Neutralteil enthältepi-- undepi--Amyrin und deren Acetate, - und -Amyrenon, sowie Viridiflorol. Die Anwesenheit von Triterpenen mit 9(11), 12-Dien-Struktur konnte nachgewiesen werden. Einige chemische Reaktionen dieser Substanzen werden beschrieben.

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From incense 11-keto--boswellic acid acetate could be isolated amongst other known acids. The neutral fraction containsepi-- undepi--amyrin and their acetates, - and -amyrenone, and viridiflorol. The presence of triterpenoids with 9(11), 12-diene structure could be proven. Some chemical reactions of these substances are described.

     

Synthesis of a branched tetrasaccharide-2-acetamido-4-o-β-d-galactopyranosyl-6-o-[o-β-galactopyranosyl-(l→4)-β-d-glucopyranosyl]-2-desoxy-d-glucose

Conclusions The branched heterooligosaccharide, 2-acetamido-4-O--D-galactopyranosyl-6-O-[O--D-galactopyranosyl (1 4)--D-glucopyranosyl]-2-desoxy-D-glucose, was obtained by a combination of the orthoester and diphenylcyelopropenyl methods of glycoside synthesis.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1421–1423, June, 1976.     

Crystal structure and characterization of the bis(n-benzyl-benzotriazole-n3)-dichloro Co(II) complex: CoCl2(C6H4N3CH2Ph)2

The structure of [CoCl₂(C₆H₄N₃CH₂Ph)₂] has been determined by X-ray crystallography. It is also characterized by elemental analysis, IR and electronic spectroscopy, and by thermogravimetric differential thermal analysis. It crystallizes in the monoclinic system, space group C2/c, with lattice parameters a = 16.133(3) , b = 11.355(2) , c = 15.637(3) , = 117.22(3)°, and Z = 8. The crystal structure of the title compound consists of monomeric molecules of [CoCl₂(C₆H₄N₃CH₂Ph)₂] with slightly distorted tetrahedron geometry for the CoCl₂N₂ chromophore. The thermal gravimetry (TG) data indicate that there are four decomposition steps with five endothermic peaks. The final product of the thermal decomposition is CoCl₂. Elemental analysis and the electronic and IR spectra are in agreement with the structural data.Original Russian Text Copyright © 2004 by F. Jian, H. Wang, and H. XiaoTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 723–728, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Indole derivatives

It has been established that the cyclization of arylhydrazones of 3-(-ethoxycarbonylethyl)1-methylpiperidin-4-one is accompanied by a rearrangement and leads to a 1,2,3,4-tetrahydropyrimido[3,4-a]indole derivative [1], The cyclization of arylhydrazones of 2-(-methoxycarbonylethyl)cyclohexanone under the same conditions forms indole and 3H-indole derivatives.For Communication XXXI, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 7, pp. 927–930, July, 1970.     

Physicochemical characterization of boro- and gallo-silicate isomorphs ofβ-zeolite

The crystalline isomorphs of-zeolite containing boron or gallium in the framework positions have been synthesized and the products characterized by comparing them with Al- zeolite. Evidence for the presence of B or Ga in the zeolite lattice framework has been confirmed by spectroscopic (XRD, IR and²⁹Si,²⁷Al and¹¹B MASNMR), DTA/TG, ion exchange, sorption and catalytic activity results. Chemical analysis and NMR confirm the absence of any significant amount of Al in the zeolite (SiO₂/Al₂O₃=2000). The XRD pattern of the as-synthesized B- and Ga- compounds matched well with that of Al- zeolite. Lattice B and Ga leads to a change in the X-rayd values. Framework and bridging hydroxyl stretching IR bands of-zeolite are shifted due to incorporation of gallium and boron into the zeolitic framework. MASNMR spectra of¹¹B and²⁹Si also suggest the presence of tetrahedrally coordinated B(III) or Ga(III) ions in the-zeolite framework. B and Ga-zeolites exhibit significant ion exchange capacity and catalytic activity in them-xylene isomerization reaction. The shifts in the IR bands towards higher frequency in B- and lower frequency in Ga-, the observed ion exchange capacities and catalytic properties, indicate the presence of B³⁺ or Ga³⁺ ions in the framework of-zeolite.     

Substituted 1,2-Thiazetidine 1,1-Dioxides. Synthesis of (<Emphasis Type="Italic">RS</Emphasis>)- and (<Emphasis Type="Italic">S</Emphasis>)-1,2-Thiazetidine-3-acetic Acid 1,1-Dioxide and its Reactions with Amino Acids and Dipeptides

Summary. (RS)-2-tert-Butyldimethylsilyl-1,2-thiazetidine-3-acetic acid 1,1-dioxide prepared from (RS)-S-benzyl--homocysteine was condensed via DCC/NHS with various L-amino acid esters or dipeptide esters yielding N-silylated -sultam peptides. A -sultam active ester was isolated as an intermediate. Desilylation with TBAF in THF yielded stable N-unsubstituted products, and deprotection of the benzyl esters was achieved by catalytic hydrogenation. (S)-S-Benzyl--homocysteine was obtained by fractional crystallization of the brucine salt of the racemate and transformed into benzyl (S)-1,2-thiazetidine-3-acetate, which was on the other hand synthesized by an enantiospecific route from -benzyl Boc-L-aspartate. Some -sultam peptides were prepared from the (S)-enantiomer, and finally some -sultam peptides containing D-Ala units were obtained.     

Octahedral and tetrahedral configuration changes of nickel(II) chloro complexes from spectrophotometric studies in aprotic solvents

Four NiII chloro complexes were identified spectrophotometrically in aprotic media such as DMSO, DMF and propylene carbonate for the first time. An original multiwavelength numerical treatment, based on a Marquardt method, results in the determination of the individual electronic spectra of the mononuclear chloro complexes and of their stability constants, the values of which indicate the presence of rather weak complexes in DMSO and DMF, much stronger in the less solvating propylene carbonate solvent. The overall stability constants calculated for the NiII chloro complexes are: 1=52, 2=140, 3=160, 4=210 in DMSO, 1=60, 2=110, 3=900, 4=15000 in DMF, 1=1.6×109, 2=6.4×1015, 3=2.7×1021, 4= 5.1×1026 in PC.The solvent effect is discussed in terms of the quantitative results obtained from this spectrophotometric study and reveals that the stability of the complexes is an inverse function of the donor properties of the solvent. This result illustrates the general behavior of complex formation in dipolar aprotic solvents, i.e. the substitution of one solvent molecule in the inner coordination sphere by the ligand is easier if the solvation strength of the solvent is lower. The solvent effect is also described in terms of the variation of shifts of the calculated absorption maxima for the individual electronic spectra of the chloro complexes. This result is used to identify clearly at which step of coordination the octahedral configuration of the nickel ion changes to the tetrahedral configuration, by comparison with the well-known structural properties of these complexes in the solid state.     

Spectroscopic and thermodynamic studies on solvatochromic nickel(II) complexes

Summary The solvatochromic and thermochromic behaviour of a series of mixed Ni(II) complexes with unsubstituted and substituted -diketones and diamines in the solvents 1,2-dichloroethane (DCE), acetonitrile (An), acetone (AC),n-butanol (n-BuOH), formamide (FA), N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO) and pyridine (PY) has been studied and characterized on the basis of electronic spectra. Spectrophotometric methods have been used to evaluate equilibrium constants and their enthalpic and entropic terms for the formation of Ni(-dik)(diam)L ⁺ and Ni(-dik)(diam)L ₂ ⁺ . Increasing donor strength of the donor-solvents (L) and (or) increasing electronwithdrawing parameters of the substituents at the -diketone and the diamine ligands lead to increasing formation constants, paralleled by relative increase in the stability of the five-coordinated species Ni(-dik)(diam)L ⁺. The results are discussed in terms of the extended donor-acceptor concept.On leave of absence from the Faculty of Education, Ain Schams University, Roxy, Cairo, Egypt     

A radioactive method for the localization and estimation of sitosterol on paper chromatograms

Summary A new method is described for the localization and estimation of sitosterols on a radiochromatogram. The method depends upon the addition of rado-iodine at the double bond of sitosterol on the developed paper chromatogram. It denotes the presence of - and -sitosterol in the two materials investigated with new R_f values in a new developing system.

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Zusammenfassung Eine radiochemische Methode wird beschrieben zur Lokalisierung und Bestimmung von Sitosterinen auf Papierchromatogrammen. Das Verfahren beruht auf der Addition von radioaktivem Jod an die Doppelbindung des Sitosterols auf dem entwickelten Chromatogramm. In zwei untersuchten Substanzen konnten mit einem neuen Lösungsmittelsystem - und -Sitosterin nachgewiesen werden.

     

Synthesis ofN-chioroacetyl-β-glycopyranosylamines,derivatives of monosaccharides and lactose

N-Chloroacetyl--glycopyranosylimines were synthesized from various monosaccharide (hexoses, pentoses, deoxysugars, uronic acids, and sugar phosphates) and a disaccharide (lactose) byN-acylation of the corresponding -glycosylamines with chloroacetic anhydride in DMF In some cases, treatment of rnonosacc harides with NH₃ in the presence of (NH₄)₂CO₃ in MeOH or aqueous MeOH was more efficient than the methods previously described, as it gave -glycosylarnines in higher yields.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1848–1851, July, 1996.     

Synthesis and properties of some chromium(III) β-diketonate complexes

Summary Equimolar quantities of CrCl₃ · 3THF and-diketones, -dkH, react to yield CrCl₂(-dk) · 2THF and CrCl₂(-dk) · THF complexes in coordinating and noncoordinating solvents respectively. For 1 : 2 and 1 : 3 molar ratios of reactants, derivatives of general formulae CrCl(-dk)₂ and Cr(-dk)₃ (where-dkH = acerylacetrrnc, benzoylacetonc and dibenzoylmethane) have been isolated. All complexes have been characterized by elemental analysis, molecular weights and by i.r. spectra.     

Synthesis of macrolide antibiotics Communication 3. Synthesis of the C9-C13 fragments of oleandonolide and erythronolide B

Conclusions Using Cp₂Zr(H)Cl, 1,6-anhydro-2-desoxy-2-C-methyl-3-O-benzyl-4-methylene--D-xylohexapyranose has been reduced with a high degree of stereospecificity to 1,6-anhydro-2,4-didesoxy-2,4-di-C-methyl-3-Obenzyl--D-galactopyranose, which was then converted into the C⁹-C¹³ fragments of erythronolide Band oleandonolide.Short communication [1]; previous communication [2].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2568–2572, November, 1982.     

Alkyl-substituted dipyrrylmethenes and their oxa- and thia-analogs: “structure—solvation properties” correlations

New data on the spectral properties and solution enthalpies of unsymmetrically substituted 2-(alkyl-2-pyrrolylmethylidene)methylpyrrolium bromides (or ,-dipyrrylmethene hydrobromides), their ,-, ,-isomers, as well as their oxa and thia analogs, that is, 2-(2-furylmethylidene)- and 2-(2-thienylmethylidene)-3,4,5-trimethyl-1H-pyrrolium bromides, in solutions of organic solvents of different nature are presented. A decrease in the number of substituents, as well as replacement of the heteroatom (N) in one five-membered ring of the dipyrrylmetnehe by oxygen or sulfur atoms cause a monotonic hypsochromic shift of absorption bands in the electronic absorption spectrum and weakening of the chromophore properties of the compounds. The chromophore properties of isomers are weakened from the ,- to ,- and ,-dipyrrylmethenes. Main trends in the influence of structural factors on the specific features of thermooxidative destruction of the above-mentioned compounds were analyzed.     

Surface Plasmon Resonance to Determine Apparent Stability Constants for the Binding of Cyclodextrins to Small Immobilized Guests

Surface plasmon resonance (SPR) has been used to determine apparent stabilityconstants for the non-covalent interactions of cyclodextrin (CD) hosts with smallorganic guests. This technique allows detection of the molecular interactions bymonitoring changes in refractive index at gold surfaces on which the guests areimmobilized. The magnitude of an SPR response is proportional to the mass changeat a surface, and thus the technique has most commonly been used in the past to studylarge molecules such as proteins and DNA. Now SPR has been employed to study theinteractions of CD, CD, CD, per-2,6-dimethyl-CDand Molecusol^TM (hydroxypropyl-CD) with immobilizedN-(1-adamantylmethyl)-, N-octyl-, N-benzyl-, N-(4-methylbenzyl)-,N-(4-tert-butylbenzyl)- and N-(1-pyrenylmethyl)-amides. Methods areoutlined for obtaining high-quality, reproducible binding data. The magnitudes(10²–10⁴ M^-1) and trends in the apparent stability constants so observedare generally consistent with values reported for analogous solution-phase studies. Theresults show that SPR is suitable to study host–guest interactions of small molecules such as cyclodextrins.     

Komplexe des Nickels mit p-Methylbenzamidoxim

Zusammenfassung Die Komplexbildung des p-Methylbenzamidoxims (pMB) mit Ni²⁺ wurde in neutraler und alkalischer Lösung spektrophotometrisch untersucht. In neutraler Lösung wird ein grüner Komplex 11 gebildet, dessen Bildungskonstante ₁=1,12 ist. In alkalischer Lösung werden zwei Komplexe (11 und 12) gebildet mit Bildungskonstanten ₁=4·10⁵ und ₂=0,2.

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Nickel complexes with p-methyl benzamide oxime

The complex formation of p-methyl benzamidoxime with Ni²⁺ was studied spectrophotometrically in neutral and in alkaline solution. A green complex 11 is formed in neutral solution. Its formation constant is ₁=1.12. In alkaline solution two complexes (11 and 12) are formed. Their formation constants are ₁=4·10⁵ and ₂=0,2 resp.

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