Novel Route to 2‐Arylapomorphines

The synthesis of 2‐arylapomorphines (1, 2) has been accomplished using a new method involving a Suzuki‐type cross‐coupling reaction of 2‐bromoapocodeine (8) and arylboronic acids.     

A facile pathway to 2-furfurylketones

2-(Chloromethyl)furan as an electrophile reacted with lithium trialkylalkyllylbo-rates,followcl by the oxidation with H_2O_2 under basic condition to afford 2-furfurylketonesin good yields.This provides a new method for the preparation of 2-furfurylkctoncs.     

A novel chemical route to SiO_2 nanowires

A white substance was got by directly heating TiSi powder on Ti foil, under Ar+O2 atmosphere. ED, EDX, SEM and HRTEM studies reveal that the white substance consists of amorphous SiO2nanowires of smooth surface and uniform diameter (40-90 nm). X-ray-induced luminescent emission experiment shows that two broad peaks are at 430 and 570 nm. A one-dimensional growth mechanism, on the basis of the one-dimensional thermal flow during nanowire formation, is discussed.     

Free-radical addition of 2-pyrrolidinone to α-olefins

Summary When reaction is initiated with t-butyl peroxide, 2-pyrrolidinone reacts with -olefins with formation of mixtures of 3- and 5-alkyl-2-pyrrolidinones with the latter isomer in the predominating amount.This article is published in accordance with a resolution of the Conference of Chief Editors of Journals of the Academy of Sciences of the USSR of July 12, 1962, as a dissertation paper by G. I. Nikishin.Translated from Izvestiya Akademii Nauk SSSR, Seria Khimicheskaya, No. 10, pp. 1843–1847, October, 1964     

A Possible Reaction Channel from BrONO to BrNO2

A possible isomeriztion channel from BrONO( bromine nitrite) to BrNO2 (nitryl bromide) is predicted by means of MP2 and QCISD(T) (single-point) methods.The channel is a direct bromine abstraction reaction from BrONO molecule by NO2 in which the forward reaction barrier is 89.30 kJ/mol at final UQCISD(T)/6-311 G(2df)//UMP2/6-311G(d) level of theory with zero-point energies included,The result can explian the available experiments very well.     

Approach to N-Alkoxy-2-oxoindole for Mimicing SERMs Structure

Treatment of N-alkoxyamides with bis（trifluoroacetoxy）iodobenzene generated electron deficient nitrogen species, which readily cyclized onto aromatic ring to give N-alkoxy-2- oxoindoles. The effect of different substituent on aromatic ring to the electrophilic substitution was studied.     

A redox-hydrothermal route to β-MnO2 hollow octahedra

Beta-Manganese dioxides' (β-MnO₂) hollow octahedra have been prepared by a synergetic redox reaction using cuprous chloride (CuCl) and hydrochloric acid (HCl) as reductants and potassium permanganate (KMnO₄) as oxidant through a hydrothermal route. During the process, the self-generated chlorine (Cl₂) gas bubbles and HCl's etching appear to be necessary for the formation of MnO₂ hollow structure. The catalytic efficiency of the prepared β-MnO₂ hollow octahedra was high which has been demonstrated by the catalytic oxidation of methylene blue (MB) dye in the presence of hydrogen peroxide (H₂O₂) under natural light.     

Some Attempts to Employ the Singlet Oxygen Generated from H2O2

Some attempts to employ the singlet oxygen generated from molybdate-catalyzed decomposition of hydrogen peroxide are presented. Reduction of ascaridole with diimide is also described, along with the preliminary results of the cleavage study using Fe-cysteinate as a simple model for Fe-S type redox species. There were strong indications that S-alkylation occurred as observed in similar cleavage of the potent antimalarial qinghaosu.     

Catalytic Conversion of 2-Naphthol to 2-Hydroxy-1,4-naphthoquinone Under Mild Conditions

Introduction 2-Hydroxy-1,4-naphthoquinone (HNQ), existing in natural plants,1,2 is popularly separated and purified as dye or pigment. Recent research results show that, with the function to prevent the formation of protein coenzyme of HIV-I, HNQ can inhibit HIV virus from copying and propagating,3,4 HNQs derivatives and di-chloroallyl lawsone are also the inhibitor for RNA syn-thesis of cancer.5 It is well known that there is a rela-tionship between the side chain attached to HNQ an…     

[3 + 2] Cycloaddition of Diazomethane Derivatives to Perfluoro-2-phosphapropene

Perfluoro-2-phosphapropene ( 1 ) reacts with diazo compounds R(H)C=N₂ (R = H ( 2 a ), Ph ( 2 b ), CO₂Et ( 2 c ), Me₃Si ( 2 d )) at low temperatures regioselectively yielding via 1,3-H shift the novel 1,2,3-diazaphospholes 4 a – d . The mesomerically stabilized compounds 4 b and 4 c were characterized by NMR spectroscopy and single crystal X-ray diffraction studies. Using diphenyldiazomethane 5 as partner for 1 , the cycloaddition is spontaneously followed by N₂ elimination to give the crystalline phosphirane derivative 7 . The analogous reaction of 1 with 9-diazofluorene 9 unexpectedly leads to the so-far unknown 1,2-diphosphinane compound 11 . Quantum chemical calculations for the gas phase on DFT and RHF level prove that for both the perhydro- and the perfluoro-2-phosphapropene the [3 + 2]-cycloaddition is kinetically determined and that, due to high stability of the products, the thermodynamic equilibrium with the slightly more stable isomers is not accessible.     

Facile Route to Control over the Morphological Evolution of β-Ga_2O_3 from Nanowires to Nanoflags and to Nanosheets

We report the fabrication of β-Ga_2O_3 nanostructures on Au-coated(0001) sapphire substrate by chemical vapor deposition. The morphologies and structural properties of β-Ga_2O_3 nanostructures were characterized by scanning electron microscopy, X-ray diffraction and transmission electron microscopy. Different morphologies including nanowire, nanoflag and nanosheet were controllably synthesized by adjusting the important growth parameters of ambient source contents. It is suggested that the relative ratio of oxygen and gallium contents plays a significant role in determining the morphologies of β-Ga_2O_3 nanostructure.     

Cyclization of monoethanolamine to aziridine over Cs2O–P2O5/SiO2

Several commercially available supports were examined for cyclization of monoethanolamine to aziridine, and SiO₂ was found to yield the best results. The obtained results indicated that selectivity of aziridine was mainly influenced by support. The catalysts were characterized by NH₃-TPD and XRD. It was found that SiO₂ with lower acidity could inhibit the intermolecular condensations, and thus favored the formation of aziridine. The Cs₄P₂O₇ phase was confirmed as the active site in the supported cesium phosphate catalyst. The reaction parameters were also optimized and a yield of 52% aziridine was obtained over 200?h. Thus, a continuous process for the cyclization of monoethanolamine to aziridine has been established.     

From Bq cm−3 to Bq cm−2 (and conversely)—part 2: useful dataset to apply the conversion to decommissioning operations

Journal of Radioanalytical and Nuclear Chemistry - A large set of key parameters is provided to use in decommissioning operations, the conversion method fully described in the companion paper...     

Erratum to: Nanoscale composite materials in the system SiO2–TiO2

Nanoscale composite materials based on the SiO₂–TiO₂ system were prepared in the form of co-precipitated composites and core SiO₂–shell TiO₂ composites, with specific surface area 150–650 m²/g and sorption volumes 0.1–1.0 cm³/g. It is shown that variation of phase composition and morphology permits to change their structural-adsorption properties and nanocrystallites size after thermal treatment. It is discovered that co-precipitated composite materials differ from core SiO₂–shell TiO₂ composites by a component interaction degree. It determines the difference of the titan-containing component crystallization process and alteration of their structural-absorption properties after thermal treatment. The results of the tests of composites as photocatalysts for Rhodamine B decomposition reaction, as catalysts of Hantzsch and Biginelli reaction, and as fillers in electrorheological fluids are shown.     

Reversible and Selective CO2 to HCO2− Electrocatalysis near the Thermodynamic Potential

Reversible catalysis is a hallmark of energy-efficient chemical transformations, but can only be achieved if the changes in free energy of intermediate steps are minimized and the catalytic cycle is devoid of high transition-state barriers. Using these criteria, we demonstrate reversible CO₂/HCO₂⁻ conversion catalyzed by [Pt(depe)₂]²⁺ (depe=1,2-bis(diethylphosphino)ethane). Direct measurement of the free energies associated with each catalytic step correctly predicts a slight bias towards CO₂ reduction. We demonstrate how the experimentally measured free energy of each step directly contributes to the <50 mV overpotential. We also find that for CO₂ reduction, H₂ evolution is negligible and the Faradaic efficiency for HCO₂⁻ production is nearly quantitative. A free-energy analysis reveals H₂ evolution is endergonic, providing a thermodynamic basis for highly selective CO₂ reduction.     

Theoretical Study of the Dehydration Process of MgCl_2·4H_2O to MgCl_2·2H_2O

Density functional theory was employed to study the dehydration mechanism of MgCI_2·4H_2O. Analysis of potential energy surface(PES) of possible pathways indicated that the most possible way was one of the water molecules halfly dissociated with an elongated bond distance with Mg~(2+),where electrostatic interaction played a leading role; another water molecule dissociated sequentially. It was in agreement with the result from differencial thermal analysis. The dehydration process of MgCI_2·4H_2O was clarified theoretically,promoting the theoretical study of dehydration of MgCI_2·2H_2O.     

An optimum route to prepare FePO4·2H2O and its use as an iron source to synthesize LiFePO4

Science China Chemistry - LiFePO4 cathode material is synthesized by a simple solid-state reaction method with FePO4·2H2O as iron source and citric acid as reductive agent and carbon source....     

β-Olefination of 2-alkynoates leading to trisubstituted 1,3-dienes

A phosphine-mediated olefination of 2-alkynoates with aldehydes forming 1,3-dienes with high E-selectivity and up to 88% yield is described. Reaction conditions are optimized and reactions are demonstrated for various aryl, alkyl, and alkenyl aldehydes and for ethyl 2-alkynoates with different substituents in the δ-position. Proof of concept is shown for the generation of a β,γ-unsaturated lactone by intramolecular olefination, and furthermore the use of the generated 1,3-dienes in the Diels-Alder reaction has been demonstrated.     

Theoretical Study on Photoisomerization of 2-Methylfuran to 3-Methylfuran

1 INTRODUCTION 2-Methylfuran belongs to the basic heteroaromatic compounds relevant to many fields of modern che- mistry, ranging from the study of natural products and biologically active substances to the develop- ment of building blocks for organic synthesis and conducting polymers[1]. Since the photochemistry ofR-furan was gradually recognized in 1960s[2～7], lots of interest has been aroused. Herein we only study one branch of photoche- mistry of R-furan: the isomerization of 2-methy…     

Heterocyclization of ω-Bromo-2-trichloroacetyl Cycloalkanones to Isoxazole Derivatives

A new series of brominated 3,4-polymethylene-5-hydroxy-5-trichloromethyl-4,5-dihydroisoxazoles (2a–d) has been regiospecifically obtained from the reaction of ω-bromo-2-trichloroacetylcycloalkanones with hydroxylamine in 79–87% yield. Dehydration of the 5-hydroxydihydroisoxazoles 2a–d can be effected with concentrated sulfuric acid at 25 °C to give the regioisomeric brominated 3,4-polymethylene-5-trichloromethylisoxazoles (3a–d). In contrast, the dehydration of 5-hydroxydihydroisoxazoles with sulfuric acid in ethanol solution at 65 °C, for transformation of trichloromethyl to carboxyl group, was reproducible only with 9-bromo-3-trichloromethyl-3,3a,4,5,6,7,8,9-octahydrocycloocta[c]isoxazole-3-ol, 2d, leading to isoxazolecarboxylate 4d. The structural assignments of all isolated products are based on the analysis of their ¹H and ¹³C NMR spectral data.