Fluordiazadiphosphetidine, 17. Mitt.

The reactions of (CH₃NPF₃)₂ and F₃P(CH₃N)₂PF₂OCH₃ with lithium-1,1,1-trimethyl-N-(trimethylsilyl)-silanamide yield two new dispiro-compounds:XF₂P(CH₃N)₂PF(NSiCH₃)₂PF(CH₃N)₂PF₂ X withX=F, OCH₃. Synthesis, mass-spectra and X-ray structures are discussed.

Herrn Prof. Dr.K. L. Komarek zum 60. Geburtstag gewidmet.     

Fluordiazadiphosphetidine, 16. Mitt.

The reaction of (CH₃NPF₃)₂ with NH₃ and primary aliphatic and aromatic amines in the molar ratio 3:2 yields (CH₄NPF₄)₂ and the monoamino substituted fluordiaza-diphosphetidines. These react with N-Trimethylsilyl-methylamine to the mixed diamino substituted compounds.With 1,4-Diazabicyclo[2.2.2]octan as HF-acceptor a second step of nucleophilic substitution with NH₃ and primary amines is possible. In the case of ammonia a by- product has been identified as the 1:1 adduct of (CH₃NPF₂NH₂)₂ with 1,4-diazabicyclo[2.2.2]octan.

Herrn Prof. Dr.O. Hromatka zum 80. Geburtstag gewidmet.     

Conformational Analysis of Germacrane Sesquiterpene Lactones. 1(10)Z,4E- and 1(10)E,4Z-Germacranolides

Molecular mechanics was used to study the structures of 1(10)Z,4E- and 1(10)E,4Z-germacranolides. Possible conformers, their probabilities, and barriers to conformational transitions were determined     

Flow Injection Analysis of Benzoyl Peroxide Using N,N,N,N-Tetramethyl-p-phenylenediamine (TMPDA) and Surfactants

Abstract

The flow injection analysis of benzoyl peroxide using N,N,N,N-tetramethyl-p-phenylenediamine (TMPDA, also known as Wurster's reagent) and a solvent system including the surfactant sodium dodecyl sulfate (SDS) and cerium(IV) as a catalyst at pH 6.0 at 612 nm was investigated. The method was applied to the analysis of acne cream and flour. The study included a 26-metal-ion search for other possible methods of catalysis and a buffer study of SDS and cetyltrimethyl ammonium bromide (CTAB).     

A computational study of surface tension determination of dense fluids as benzene,toluene, methanol,ammonia, ethylene,and carbon monoxide

In this study, the parameters of linear isotherm regularity, which called LIR equation state used to compute the surface tension of some dense fluids as benzene, toluene, methanol, ammonia, ethylene, and carbon monoxide. An expression has derived for radial distribution function (RDF) at constant temperature, g (σ), for a real fluid by the use of LIR. This expression, which is related to intermolecular interaction, can be used to describe the temperature–density dependency of RDF at constant temperature, g (σ, ρ, T). In addition, we derive an expression for surface tension of dense fluids (CO, C₆H₆, C₆H₅CH₃, CH₃OH, NH₃, and C₂H₄) using the LIR and g (σ, ρ, T). Unlike previous models, it has shown that, surface tension can obtain without employing ΔH and ΔS. Only P-V-T experimental data have been used to calculate the surface tension. Comparison of the calculated values of surface tension by LIR with the values obtained experimentally show this method is not precise. This problem has led us to try to obtain the expression for surface tension using the extended parameters A, B (A and B are the temperature-dependent parameters which noticeably are depended on attraction and repulsion). The obtained result shows that the accuracy of this method is very high and quite admissible.     

Fluordiazadiphosphetidine, 20. Mitt. Die Dehydrofluorierung zwitterionischer und die Hydrofluorierung neutraler,hydrazinsubstituierter Fluordiazadiphosphetidine

In the presence ofEt ₃N·PF₅, F₄P^–(CH₃N)₂PF₂NHNH⁺(CH₃)₂ (I) looses one molecule of HF to yield F₃P(CH₃N)₂PF₂NHN(CH₃)₂ (II). The reaction ofI withDABCO (1,4-diazabicyclo[2.2.2]octane) yieldsDABCO·2H⁺⁺(CH₃NPF₄) ₂ ^–– (III) and [CH₃NPF₂NHN(CH₃)₂]₂ (IV). Even in the presence of CsF,II does not react with HF.

     

3-Ferrocenyl-3-(1-naphthyl)cyclopropene. Synthesis, structure, and chemical transformations

Crystalline 3-ferrocenyl-3-(1-naphthyl)cyclopropene was prepared by dehydrobromination ofZ- andE-2-bromo-1-ferrocenyl-1-(1-naphthyl)-cyclopropanes by Bu^tOK in DMSO. The resulting compound and the startingZ-monobromocyclopropane were characterized by X-ray diffraction analysis. The obtained cyclopropene reacts with 1,3-diphenylisobenzofuran to give a [4+2]-cycloadduct. The small ring opens upon treatment with HBF₄ etherate to afford isomericZ- andE-prop-1-enes and 1-ferrocenyl-3H-benzo[e]indene. Thermolysis of this cyclopropene results in the formation of 1-ferrocenyl-9bH-benzo[e]indene. In all cases, opening of the small ring is accompanied by exclusive alkylation of the naphthalene moiety. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 499–506, March, 1998.     

Synthesis and chemical transformations of silicon-containing derivatives ofN,N-dimethylhydrazine

Reactions of carbofunctional organosilicon compounds withN,N-dimethyl-N′-trimethylsilylhydrazine andN,N-dimethyl-N′,N′-bis(trimethylsilyl)hydrazine were studied. The composition and structure of the reaction products were found to be dependent on the reagent nature and the reaction conditions. 1,4-Dimethylamino-2,2,5,5-tetramethyl-1,4-diaza-2,5-disilacyclohexane, a first representative of a new type of 2,5-disilapiperazines, was synthesized. A scheme of its formation was proposed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 169–173, January, 1999.     

Synthesis,characterization, antibacterial,and thermal studies of unsymmetrical Schiff-base complexes of cobalt(II)

Cobalt(II) complexes of a new series of unsymmetrical Schiff bases have been synthesized and characterized by their elemental analyses, melting points, magnetic susceptibility, thermogravimetric analysis, differential scanning calorimetry, infrared (IR), and electronic spectral measurements. The purity of the ligands and the metal complexes are confirmed by microanalysis, while the unsymmetrical nature of the ligands was further corroborated by ¹H-NMR. Comparison of the IR spectra of the Schiff bases and their metal complexes confirm that the Schiff bases are tetradentate and coordinated via N₂O₂ chromophore. The magnetic moments and electronic spectral data support square-planar geometry for the cobalt(II) complexes. The complexes were thermally stable to 372.3°C and their thermal decomposition was generally via the partial loss of the organic moiety. The Schiff bases and their complexes were screened for in vitro antibacterial activities against 10 human pathogenic bacteria and their minimum inhibitory concentrations were determined. Both the free ligands and cobalt(II) complexes exhibit antibacterial activities against some strains of the microorganisms, which in a number of cases were comparable with, or higher than, that of chloramphenicol.     

STEREOCHEMISTRY OF COMPLEXES WITH N-ALKYLATED AMINO ACIDS. VIII. CRYSTAL STRUCTURE AND CONFORMATIONAL ANALYSIS OF AQUABIS(L-N,N-DIMETHYLTHREONINATO)COPPER(II) DIHYDRATE

Abstract

The structure of blue, monoclinic (space group P2₁) crystals of aquabis(L-N,N-dimethylthreoninato)copper(II) dihydrate was determined by X-ray diffraction and refined to R = 0.030. The coordination around the copper(II) atom is distorted square-pyramidal with threonine N and O atoms in trans orientations (Cu-O 1.930(3) and 1.926(3)Å, Cu-N 2.042(3) and 2.055(3)Å, O-Cu-O 163.9, N-Cu-N 164.0°) and apical water (Cu-O(W) 2.206 Å). The shape of the coordination polyhedron was reasonably well reproduced with molecular mechanics calculations, yielding root-mean-square deviations of ten valence angles around copper to 4.5°. The calculated strain energy of the crystal conformation is about 21 kJ mol^? higher than the energy of the most stable conformer. This was tentatively attributed to the additional stabilization of molecular conformation by intermolecular hydrogen bonds in the solid state.     

Lupane triterpenoids,antioxidant potential and antimicrobial activity of Myrciaria floribunda (H. West ex Willd.) O. Berg.

Chemical composition of the methanol extract of Myrciaria floribunda leaves was investigated. The nor-lupane triterpenoids platanic acid and messagenic I acid were identified, along with other known triterpenoids (betulinic aldehyde, ursolic acid acetate and betulinic acid), a new lupane triterpenoid (2α,6α,30-trihydroxybetulinic acid) and the flavonoids catechin, quercetrin and mirycitrin. The structures were determined by spectroscopic methods (NMR, LC-MS, GC-MS). The major isolated compound was betulinic acid. The methanol extract and 2α,6α,30-trihydroxybetulinic acid were evaluated for their DPPH scavenging potential. The tested triterpenoid was one hundred times more active than betulinic acid, but less active than the extract. Screening for antimicrobial activity showed that the methanol extract was active against Staphylococcus aureus and Escherichia coli, but inactive against Candida albicans and Candida krusei, while 2α,6α,30-trihydroxybetulinic acid was inactive to all tested microorganisms.     

Small-angle scattering of polarized light. IV. Isotropic to birefringent transition for spheres

The Rayleigh-Gans-Debye approximation is used to investigate the small-angle, cross-polarized light scattering by a sphere of radius a, birefringence Δμ and relative index μ. If θ_max is the polar scattering angle of the intensity maxima, the quantity Û_max = 4πa/λ × sin (θ_max/2) behaves in two different ways according to the signs of Δμ and μ ? 1. When Δμ > 0, μ > 1 or Δμ < 0, μ < 1, then Û_max varies from 2.8 to 4.1 as Δμ increases from zero. If Δμ < 0, μ > 1 or Δμ > 0, μ < 1, then Û_max goes from 2.8 to about 6, thereafter decreasing to 4.1. Another interesting result is that the value of Û_max for a highly briefringent sphere is 4.1 only for large diameters. It decreases to 4.0 when the diameter decreases.     

Metallderivate von Molekülverbindungen. VIII. catena-Poly[(2,5,8-trioxanonan-O2,O5) lithium-methylphosphanid] — eine Verbindung mit meso-Helix-Struktur

Metal Derivatives of Molecular Compounds. VIII. catena-Poly[(2,5,8-trioxanonane-O²,O⁵) lithium-methylphosphanide] — a Compound with a meso-Helix Structure Studies of Fritz et al. [10] showed methylphosphane to be lithiated at ?60°C in 1,2-dimethoxyethane or bis(2-methoxyethyl) ether solution by stoichiometric amounts of lithium n-butanide in n-hexane. After removing the hydrocarbons almost completely by distillation and cooling the solutions to ?60°C again, colourless square crystals of (1,2-dimethoxyethane-O,O′)lithium ( 1 ) and (2,5,8-trioxanonane-O²,O⁵)lithium methylphosphanide ( 2 ) precipitate. As shown by an X-ray structure determination (monoclinic, P2₁/n; a = 805.5(1); b = 1820.6(2); c = 851.5(1) pm; β = 116.76(1)° at ?100 ± 3°C; Z = 4 formula units; R = 0.034) complex 2 forms a polymer which has the shape of an up to now scarcely noted meso-helix. Four-coordinated lithium is bound to two phosphorus (P? Li 252.9 and 253.2 pm; P? Li? P 131.8°; Li? P? Li 132.1°) and to two oxygen atoms (Li? O 203.9 and 206.8; O …? O 270.7 pm; O? Li? O 82.5°) of the inherently tridentate 2,5,8-trioxanonane ligand. As compared to the standard value (185 pm) the P? C distance (187.4 pm) is slightly lengthened. Structure determinations of (2,5,8-trioxanonane-O²,O⁵,O⁸) lithium 1-(phenylsulfonyl)alkyl compounds published some years ago [26, 27], allow a comparison of molecular parameters characteristic for the twofold or threefold coordinating chelate ligand.     

Complex compounds of Cu(II) and Zn(II) withN,N-dimethylglycine andN,N-diethylglycine in water and in water—Methanol system

The complex equilibria of the systems: copper—N,N-dimethylglycine, zinc—N,N-dimethylglycine, copper—N,N-diethylglycine, and zinc—N,N-diethylglycine have been studied by computer analysis of potentiometric data. The stability constants of the complexes formed in these systems are reported. A discussion is presented about the influence of the substituent and the solvent on the dissociation constants of the amino acids and the stability constants of their complexes with metals.¹H NMR and IR studies indicate that both functional group of the ligands are involved in complex formation.

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Cu(II)- und Zn(II)-Komplexe mitN,N-Dimethylglycin undN,N-Diethylglycin in Wasser und Wasser—Methanol-Lösung

Zusammenfassung Anhand der Computer-Analyse von potentiometrischen Daten wurden die Bildungsgleichgewichte von Kupfer(II)- und Zink(II)-Komplexen mitN,N-Dimethylglycin undN,N-Diethylglycin untersucht. Die Beständigkeitskonstanten der gebildeten Komplexe wurden angegeben. Der Einfluß von Liganden und Lösungsmitteln auf Beständigkeit und Dissoziationskonstanten dieser Komplexe wurde diskutiert. Es wurde mittels¹H-NMR- und IR-Untersuchungen festgestellt, daß bei der Bildung der Komplexe beide funktionellen Gruppen der Liganden teilnehmen.

     

Bis(1,2-dimethoxyethan-O,O′)lithium-phosphanid, -arsanid und -chlorid – drei neue Vertreter des Bis(1,2-dimethoxyethan-O,O′)lithium-bromid-Typs

Metal Derivatives of Molecular Compounds. IX. Bis(1,2-dimethoxyethane- O,O′ )lithium Phosphanide, Arsanide, and Chloride – Three New Representatives of the Bis(1,2-dimethoxyethane- O,O′ )lithium Bromide Type Experiments to obtain thermally unstable lithium silylphosphanide at –60 °C from a 1,2-dimethoxyethane solution resulted in the isolation of its dismutation product bis(1,2-dimethoxyethane-O,O′)lithium phosphanide ( 1 ). The homologous arsanide 2 precipitated after a frozen solution of arsane in the same solvent had been treated with lithium n-butanide at –78 °C. Unexpectedly, too, the analogous chloride 3 and bromide 4 were formed in reactions of 1-chloro-2,2-bis(trimethylsilyl)-1λ³-phosphaethene with (1,2-dimethoxyethane-O,O′)lithium bis(trimethylsilyl)stibanide and of lithium 1,2,3,4,5-pentaphenyl-2,3-dihydro-1λ³-phosphol-3-ide with ω-bromostyrene, respectively. The monomeric complexes 1 {–100 ± 3 °C; a = 1391.1(4); b = 809.8(2); c = 1249.1(3) pm; β = 102.84(2)°}, 2 {–100 ± 3 °C; a = 1398.3(4); b = 819.8(3); c = 1258.5(4) pm; β = 103.35(2)°} and 3 {–100 ± 3 °C; a = 1308.4(2); b = 788.2(1); c = 1195.6(1) pm; β = 95.35(1)°} crystallize in the monoclinic space group C2/c with four solvated ion pairs in the unit cell; they are isotypic with bis(1,2-dimethoxyethane-O,O′)lithium bromide ( 4 ) {–73 ± 2 °C; a = 1319.0(2); b = 794.1(1); c = 1214.3(2) pm; β = 96.22(1)°}, already studied by Rogers et al. [13] at room temperature. The neutral complexes show a trigonal bipyramidal configuration of symmetry C₂, pnicogenanide or halide anions occupying equatorial sites {Li–P 260.4(4); Li–As 269.8(6); Li–Cl 238.6(7); Li–Br 256.3(10) pm} and the chelate ligands spanning equatorial and axial positions {Li–O_eq 205.4(4) to 207.4(4); Li–O_ax 208.9(3) to 215.5(2) pm}. The coordination within the (dme)₂Li fragment, the Li–X distances (X = P, As, Cl, Br), the structure of the chelate rings, and the packing of the neutral complexes are discussed in detail.     

Determination of the molecular weight and other physicochemical properties of poly(bubylene glycol) 1000 by gradient RPHPLC and measurement of the ELSD, UV, and fluorescence responses

Summary Molecular weight and other physicochemical data for poly(butylene glycol) 1000 (PBG 1000) have been determined by use of a new, highly efficient, gradient reversed-phase high-performance liquid-chromatographic (RPHPLC) procedure. Separation of the native material or its α, ω-bis(1-naphthylurethane) derivative was achieved on a C₁₈ stationary phase with a ternary acetonitrile-water-tetrahydrofuran mobile phase. Detection was achieved by measurement of the signal response from evaporative light scattering (ELSD), UV, and fluorescence (FD) detection. Proof that all the oligomers contained in the sample had been separated by the method was obtained by liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry (LC-ESI-TOFMS). It was also confirmed by this technique that di(butylene glycol) is the lowest homologue in the sample. Although the dimer was also observable in the HPLC-UV trace of the PBG 1000 α, ω-bis(1-naphthylurethane) derivative, it was obviously too valatile to be seen in the ELSD trace; tri(butylene glycol) was, nevertheless, still recognizable with sufficient signal intensity. Because all the homologues were separated to baseline, the method was used to calculate the number- and weight-average molecular weights,M _n andM _w, both from peak areas and from peak heights. The best fit to data obtained from end-group titration were obtained from calculations based on the HPLC-UV response;M _n values of 948 and 937 were obtained from peak heights and areas, respectively.M _n andM _w values calculated from the ELSD trace obtained from native PBG 1000 were substantially (ca 10%) lower that those calculated from the UV trace obtained from the α, ω-bis(1-naphthylurethane) derivative. Similar differences were also discovered by comparing theM _n andM _w values obtained from UV and FD-values were approximately 20% higher for FD. When the retention times of individual oligomers, from either ELSD of the native sample or from UV-FD of the α,ω-bis(1-naphthylurethane) derivative, were plotted against the number of repeat units,P, the ELSD curve approaches the UV-FD curve at values ofP of approximately 60. This observation can be explained by the pronounced contribution of the hydrophobic end-groups to the overall retention of PBG 1000; the effect of this decreases with increasing chain length and becomes nearly independent ofP only for a very high degree of polymerization. Papers dedicated to Professor Dr. Heinz Engelhardt on the Occasion of his 65th birthday     

Metalation of 2-Methyl-N-phenylbenzamide withn-butyllithium. Formation ofN,3-diphenyl-1-isoquinolinamine by subsequent reaction with benzonitrile

2-Methyl-N-phenylbenzamide was metalated with two equivalents ofn-butyllithium. Benzonitrile was allowed to react with the organometalic intermediate thus formed to yieldN,3-diphenyl-1-isoquinolinamine.

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Metallierung von 2-Methyl-N-phenyl-benzamid mitn-Butyllithium und Bildung vonN,3-Diphenyl-1-isochinolinamin durch anschließende Reaktion mit Benzonitril

Zusammenfassung Reaktion von Benzonitril mit der Di-Lithiumverbindung aus 2-Methyl-N-phenylbenzamid und 2 moln-Butyllithium liefertN,3-Diphenyl-1-isochinolinamin.

     

Facile Synthesis of (Z,E)-9,11-Hexadecadienal,the Major Sex Pheromone Component of the Sugarcane Borer Diatraea saccharalis: An Efficient Strategy for Synthesis of (Z,E)-Dienic Pheromones

Practical and improved procedures for the synthesis of 7-bromo-(Z,E)-4,6-heptadienal by Pd(II)-catalyzed coupling reaction were developed. Based on the improved method, an efficient and stereoselective synthesis of (Z,E)-9,11-hexadecadienal, the main pheromone component of the sugarcane borer, Diatraea saccharalis, was achieved in 38% overall yield, which more desirable then previously reported methods. The stereochemistry relied on cross-coupling between Grignard reagent and protected 7-bromo-(Z,E)-4,6-heptadienal. The concise and facile synthetic strategy described herein provided a generally synthetic approach to other (Z,E)-dienic compounds.     

Chain extension of polyesters PET and PBT with N,N′-bis (glycidyl ester) pyromellitimides. I

Three N,N′-bis (glycidyl ester imide) of pyromellitic acid (diepoxides) were prepared and were used as chain extenders for poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PBT). The typical reaction conditions for the coupling of the polyester macromolecules were heating with the chain extender under argon atmosphere above the melting temperature (280°C for PET and 250°C for PBT) for several minutes. The Characterization of the samples, obtained at variable residence times in the reactor, was based on solution viscosity measurements and carboxyl and hydroxyl end-group determinations. Two of the diepoxides used gave satisfactory results. Starting from a PET having intrinsic viscosity [η] = 0.60 dL/g, and carboxyl content CC = 42 eq/10⁶ g, one could obtain PET with [η] = 1.15 dL/g and CC = 16 eq/10⁶ g within 30 min at 280°C. Analogous results were observed for PBT. The hydroxyl content of polyester in all cases was increased. When the quantity of the chain extender used was higher than that theoretically required for its reaction with all carboxyl end groups of the polyester, this resulted in some gel formation indicative of crosslinking. © 1995 John Wiley & Sons, Inc.     

Immobilization,characterization, and laboratory-scale application of bovine liver arginase

Arginase isolated from beef liver was covalently attached to a polyacrylamide bead support bearing carboxylic groups activated by a water-soluble carbodiimide. The most favorable carbodiimide wasN-cyclohexyl-Nt’-(methyl-2-p-nitrophenyl-2-oxoethyl) aminopropyl carbodiimide methyl bromide, but for practical purposes,N-cyclohexyl-Nt’-morpholinoethyl carbodiimide methyl tosylate was used. The optimal conditions for the coupling procedure were determined. The catalytic activity of the immobilized arginase was 290–340 U/g solid or 2.9–3.4 U/mL wet gel. The pH optimum for the catalytic activity was pH 9.5, the apparent temperature maximum was at 60°C and K_mapp was calculated to be 0.37M L-arginine. Immobilization markedly improved the conformational stability of arginase. At 60°C, the pH for maximal stability was found to be 8.0. The immobilized arginase was used for the production of L-ornithine and D-arginine.