Synthesis and Reactivity of the First Stable λ5-Phosphaacetylene

Abstract

The synthesis and reactivity of he P-bis(diisopropylamino) trimethylsilylphosphaacetylene (bp 75–80°C/10^?2) is reported. Addition of trimethylsilyltriflate to this compound leads to a stable methylenephosphonium salt which has been characterized by an X-ray diffraction study.     

Preparation of acetylenic γ-diols,and some of their reactions

Summary Six acetylenic-diols were prepared for the first time from 3-butyn-2-ol and aliphatic ketones by the Favorskii reaction.     

Synthesis and Isolation of α-Oxo Sulfines

The synthesis of several α-oxo sulfines is discribed. Various α-oxo sulfines can be isolated as such. The Diels-Alder reaction of these sulfines with 1,3-dienes can be catalyzed by Lewis acids.     

Preparation and antibacterial activity of aromatic derivatives of β-aminopropionic and γ-aminobutyric acid

Ten aromatic derivatives of β-aminopropionic acid and γ-aminobutyric acid were prepared.Their compositions and structures were identified by elemental analysis,IR,and 1H NMR.They have been examined for their antibacterial action against Staphylococcua aurens and Escherichia coli.These compounds showed higher activity than the aromatic derivatives of ct-amino acid which were reported previously.The general conclusion to be drawn is that the distance between amino and carboxylic group in these molecules could affect their antibacterial activity.Furthermore,those compounds with p-methyl substituent in phenyl ring exhibit higher activity than the others,and all the compounds exhibit higher activity against Escherichia coli and against Staphylococcua aureus.     

Preparation of γ-Al_2O_3 composite membrane and examination of membrane defects

A boehmite sol with a narrow particle size distribution and most probable diameter of 35 nm was prepared by peptization of boehmite suspension with HNO3 An unsupported γ-Al2O3 membrane made from the above sol possessed a narrow pore size distribution,with an average pore size of 4.8 nm and 320 m2/g specific surface area.A supported y-Al2O3 membrane produced by repeating dipping-drying-calcination procedure twice was proven to be defect-free by gas permeation measurements and SEM.     

Reactivity of Various α-Halo Ketones in One-Pot Synthesis of γ-Iminolactones

The highly reactive 1:1 intermediate generated in the reaction of tert-butyl isocyanide and dialkyl acetylenedicarboxylate is trapped by α-halo ketones to produce halogenated iminolactones as the sole product in good yields.     

Preparation of Cationic Membrane of Polyethylene Film by γ-Irradiation

Grafting of acrylic acid onto PE film by a pre-irradiation method was studied. In order to prevent formation of homopolymer, Mohr salt (NH₄)₂Fe(SO₄)₂ · 6H₂O was used, and the reaction was carried out in the presence of a swelling agent, such as methanol. The influence of different factors, such as dose, dose rate, and temperature, on the kinetics of the reaction was studied. The infrared spectrum of the grafted acrylic acid onto PE shows bands characteristic of carboxylic acids, which demonstrates that grafting has occurred. The grafting sites were shown to be of a semi-spongy shape and irregular structure which is thought to be due to the copolymerization of acrylic acid onto PE film.     

Preparation and adsorption kinetics of porous γ-glycidoxypropyltrimethoxysilane crosslinked chitosan–β-cyclodextrin membranes

Porous structured chitosan–β-cyclodextrin membranes were synthesized by incorporating β-cyclodextrin polymers as the functional reagent and using γ-glycidoxypropyltrimethoxysilane as crosslinking agent. Compared with chitosan itself, the synthesized membranes showed significant changes in the molecular constitutions, crystalline and thermal properties. It was found that the mol ratio of the epoxy groups of γ-glycidoxypropyltrimethoxysilane to the free amino groups of chitosan, as well as the solvent evaporated time, largely influenced the pore size and water content of the membranes. The effects of the initial concentration of adsorbate and the pH on the adsorption of hydroquinone were investigated by the spectrophotometry. Kinetic studies show the adsorption is a pseudo-second order process. The adsorption is endothermic and chemically activated reaction with activation energy of 70.0 kJ mol⁻¹.     

Protonation of γ-Butyrolactone and γ-Butyrolactam

Abstract : γ-Butyrolactone and γ-butyrolactam were reacted in the superacidic systems XF/MF₅ (X=H, D; M=As, Sb). Salts of the monoprotonated species of γ-butyrolactone were obtained in terms of [(CH₂)₃OCOH]⁺[AsF₆]⁻, [(CH₂)₃OCOH]⁺[SbF₆]⁻ and [(CH₂)₃OCOD]⁺[AsF₆]⁻ and the analogous lactam salts in terms of [(CH₂)₃NHCOH]⁺[AsF₆]⁻, [(CH₂)₃NHCOH]⁺[SbF₆]⁻ and [(CH₂)₃NDCOD]⁺[AsF₆]⁻. The salts were characterized by low temperature Raman and infrared spectroscopy and for both protonated hexafluoridoarsenates, [(CH₂)₃OCOH]⁺[AsF₆]⁻ and [(CH₂)₃NHCOH]⁺[AsF₆]⁻, single-crystal X-ray structure analyses were conducted. In addition to the experimental results, quantum chemical calculations were performed on the B3LYP/aug-cc-pVTZ level of theory. As in both crystal structures C⋅⋅⋅F contacts were observed, the nature of these contacts is discussed with Mapped Electrostatic Potential as a rate of strength.     

Preparation and Insecticidal Activity of the First Organofluorine Insecticide Based on β-D-Ribofuranoside Monosaccharide

Russian Journal of General Chemistry - A method was developed for the synthesis of an organofluorine derivative of β-D-ribofuranoside. Biological tests revealed high insecticidal activity and...     

Preparation and Demethylation of Hexamethyldisilane

三甲基氯硅烷和金属锂在ＴＨＦ中通过还原偶合反应生成六甲基二硅烷，反应后的ＴＨＦ和未反应的金属锂可以回收再用，并对反应有明显地促进作用，六甲基二硅烷的产率从５０％增加到７０％以上。该方法对于连续制备六甲基二硅烷具有实际意义。六甲基二硅烷在无水氯化铝催化下和氯乙酰反应，脱掉一个甲基被氯化成一氯五甲基二硅烷，反应物以当量摩尔比在室温下进行，产率一般在８０％以上，有很好的重复性。合成的两个二硅烷已用１ＨＮＭＲ、１３ＣＮＭＲ和ＩＲ进行了表征。     

Preparation and Reactions of Octasilsesquioxanes

Because of the length scales involved, nanocomposite materials incorporate extensive interfacial interactions that can result in non-linear changes in the composite property. Chemists often start from polymerizable inorganic and organic constituents in the molecule to build organic/inorganic hybrids that combine advantageous properties of disparate components. Silsesquioxanes (RSiO1.5)n, derived from e.g. RSiCl3 or RSi(OEt)3 by hydrolysis/condensation in a sol-gel process, are a class of s…     

Preparation of Thermal-responsive Chitosan-graft-N-isopropylacrylamide Membranes via γ-Ray Irradiation

A novel thermo-sensitive switching membrane has been prepared by radiation-induced simultaneous grafting N-isopropylacrylamide （NIPAAm） onto chitosan membrane. Fourier transform infrared spectroscopy （FTIR） was used to identify the structure of the grafted membranes. The surface morphology of the grafted membrane was observed from scanning electron microscopy （SEM）. Pure water flux measurements showed that water flux of the grafted membrane decreased with the increase of temperature, while that of chitosan membrane was constant. It was proved that grafted membrane was sensitive to temperature.     

Preparation and characterization of the inclusion complex of baicalein with γ-cyclodextrin: an antioxidant ability study

The formation of the complex of Baicalein with γ-cyclodextrin (γ-CD) was studied by UV–Vis absorption spectroscopy, fluorescence spectra and nuclear magnetic resonance spectroscopy (NMR) in solution. The solid inclusion complex of Baicalein with γ-CD was synthesized by the co-precipitation method. The characterization of the solid inclusion complexes have been proved by infrared spectra. The formation constant (K) of complex was determined by fluorescence method. The results suggested that in different pH solutions, γ-CD has different inclusive capacity to different forms of Baicalein. γ-CD was most suitable for inclusion in neutral media. In addition, the experimental resulted confirmed the existence of 1:1 inclusion complex of Baicalein with γ-CD. Kinetic studies of DPPH? with Baicalein and γ-CD complex were done. The results obtained indicated that the Baicalein/γ-CD complex was the most reactive form. Special configuration of complex has been proposed on NMR technique.     

Synthesis,Structure and Reactivity of Lanthanocene Complexes

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｃｈｅｍｉｓｔｒｙｏｆｏｒｇａｎｏｌａｎｔｈａｎｉｄｅｓｈａｓｅｘｐｅｒｉｅｎｃｅｄｅｘｔｒｅｍｅｌｙｉｍｐｏｒｔａｎｔｄｅｖｅｌｏｐｍｅｎｔｓｄｕｒｉｎｇｔｈｅｌａｓｔｔｗｏｄｅｃａｄｅｓ ,ａｎｄｎｕｍｅｒｏｕｓｕｎｕｓｕａｌｃｏｍｐｏｕｎｄｓｗｉｔｈｕｎｐｒｅｃｅ ｄｅｎｔｅｄｓｔｒｕｃｔｕｒｅｓａｎｄｕｎｉｑｕｅｒｅａｃｔｉｖｉｔｙｐａｔｔｅｒｎｓｈａｖｅｂｅｅｎｐｒｅｐａｒｅｄ .1ＯｒｇａｎｏｌａｎｔｈａｎｉｄｅｃｏｍｐｏｕｎｄｓｃｏｎｔａｉｎｉｎｇＬｎ—Ｃ ,…     

The Preparation and Properties of Thermosensitive Hydrogels Based on Chitosan Grafted N-isopropylacrylamide via γ-Radiation

Thermosensitivehydrogels. were prepared by graft polymerization of chitosan and N-isopropylacrylamide via ^60Co γ-radiation.The effects of monomer concentration and total irradiation dose on percent grafting and grafting efficiency were studied.The thermosensitivity and swelling properties of the hydrogels were investigated.     

Preintercalation of Layered γ—Zirconium Phosphate for Preparation of Immobilized Hemoglobin

Layered γ-Zirconium phosphate (γ-ZrP) preintercalated with butylamine,tetra(n-butylammonium)hydroxide,dimethylamine respectively,or only ultrasonificated,for preparation of immobilized hemoglobin were in vestigated in this report.     

Syntheses and structures of tetraphenylantimony γ-phenyl-and γ-thiobutylacetylacetonates

Tetraphenylantimony γ-phenylacetylacetonate (I) and tetraphenylstibium γ-thiobutylacetylacetonate (II) are synthesized by the reaction of pentaphenylantimony with γ-phenylacetylacetone or γ-thiobutylacetylacetone in toluene. According to the X-ray diffraction data, the antimony atoms in complexes I and II have a distorted octahedral coordination. In complex I, the Sb-C bond lengths are 2.155(2)–2.170(1) Å, and the Sb-O(1), Sb-O(2) and O(1)-C(2), O(2)-C(4) in the heterocycle are 2.215(1), 2.227(1) and 1.282(2), 1.277(2) Å, respectively. In complex II, the bond lengths are the following: Sb-C 2.147(3)–2.161(3), Sb-O(1, 2) 2.281(2), 2.215(2), and O-C 1.267(3)–1.278(3) Å.     

Preparation and Crystal Structure of Paeonol

1 INTRODUCTION Paeonol, 2-hydroxyl-4-methoxyacetophenone, is one ofthe main components of Moutan Cortex. It is a traditionalChinese medicine with analgesic, sedative, antiallergic,antioxidative, antinflammatory and antimicrobial proper-ties and used as a remedy for cardiovascular and femalegenital diseases[1～3]. Moreover, it is also a valuableinartificial spicery and can be widely used in domesticchemistry[4]. But the nature of water insolubility and vola-tility makes it difficult for…     

Preparation and Characterization of Molybdotungstoniobogermanic Acid

Recently,thepreparationandpropertiesofheteropolycomplexeshaveincreasinglyattractedattentioninvariousfieldsofchendstIy,especiallyincatalysicapplicationsfortheiruniqueproperties'.Sincel988,thestudiesoffour-baseheteropolycomplexeswiththeKegginstructurehavebeenreported.Asthespecialbifunctionalcatalyticand.-lantisepsispropertyoftheheteropolycomplexescontainingniobium',andsofarthemolybdotungstoniobogermanicheteropolycomplexesinwhichthecentralatomisgermanium,havenotbeenreportedyet,ennea-tungsto-bi-mo…