La réaction du diazométhane avec les phénylsulfonyl-4, tert-butyl-4, et phénylthio-4 cyclohexanones

1971 ◽  
Vol 49 (19) ◽  
pp. 3097-3106 ◽  
Author(s):  
H. Favre ◽  
D. Gravel ◽  
Z. Hamlet ◽  
M. Ménard ◽  
J. Temler
Keyword(s):  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Dimethyl Acetal ◽  
Ex Situ ◽  
Epoxide Ring ◽  
Tert Butyl ◽  
First Case ◽  
In Situ Reactions ◽  
In Cis

This paper describes the reaction of diazomethane generated in situ, methanolic potassium hydroxide solution, on 4-phenylsulfonyl, 4-tert-butyl, and 4-phenylthio-cyclohexanones. In the latter two cases, the reaction leads to mixtures containing mostly the enlarged ketones along with minor quantities of the corresponding epoxides. In the first case, the enlarged ketone and the corresponding epoxides are formed in equal amounts. This marked increase in the production of epoxides is indicative of transannular interactions between the sulfonyl group and the intermediate betaine. In the ex situ reactions, methanolic solutions without potassium hydroxide, phenylsulfonylcyclohexanone yields the corresponding dimethyl acetal almost exclusively whereas the tert-butyl and phenylthioketones follow the same course as in the in situ reactions. Furthermore, it has been observed in all cases that, under the conditions used, the potassium hydroxide leads to opening of the epoxide rings to yield hydroxy-ethers of the type [Formula: see text]CH2—O—CH3. This epoxide-ring-opening was advantageously used in the preparation of pure epoxides from epimeric mixtures. The epoxides generated from the three ketones studied are mixtures of cis-trans isomers, rich in cis epimer.

Reactions of tert-Butyl Peroxy Esters, XIV. Further Observations on the Preparation of Dialkyl tert-Butylperoxy Phosphates

1975 ◽  
Vol 30 (9-10) ◽  
pp. 732-739 ◽  
Author(s):  
G. Sosnovsky ◽  
E. H. Zaret
Keyword(s):  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Sodium Hydride ◽  
High Yield ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Tert Butyl Hydroperoxide ◽  
Aqueous Potassium Hydroxide ◽  
Butyl Peroxide

The preparation of dialkyl tert-butylperoxy phosphates (2, R = alkyl) has been achieved by the reaction of the corresponding dialkyl phosphorochloridates (1, R = alkyl) with tert-butyl hydroperoxide either in the presence of pyridine or in the presence of aqueous potassium hydroxide solution. Neither of these routes is suitable for the preparation of dialkyl tert-butylperoxy phosphates in quantity since they yield peroxyphosphates which are contaminated either with the corresponding tetraalkyl pyrophosphates or dialkyl phosphates; the contaminants cannot easily be removed by conventional means from the peroxyphosphates. The method of choice for the preparation in high yield of large quantities of pure dialkyl tert-butylperoxy phosphates involves the interaction of the corresponding dialkyl phosphorochloridate with sodium tert-butyl peroxide which has been prepared in situ from the reaction of tert-butyl hydroperoxide with sodium hydride.

2-(3-Acylselenoureido)benzonitriles and 2-(3-Acylselenoureido)thiophene-3-carbonitriles. Preparation, Structure Elucidation, Cyclization and Retrocyclization Reactions

1999 ◽  
Vol 64 (10) ◽  
pp. 1673-1695 ◽  
Author(s):  
Jiří Šibor ◽  
Dalimil Žůrek ◽  
Radek Marek ◽  
Michal Kutý ◽  
Otakar Humpa ◽  
...  
Keyword(s):  
Quantum Chemistry ◽  
Ab Initio ◽  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Quantum Chemistry Calculation ◽  
Potassium Salts ◽  
X Ray ◽  
Chemistry Calculation ◽  
Acid Cyclization

Synthesis of 2-(3-acylselenoureido)benzonitriles and 2-(3-acylselenoureido)thiophene- 3-carbonitriles 5a-5f by addition of 2-aminonitriles 4a-4c to benzoyl- or 2,2-dimethyl- propanoylisoselenocyanate and their cycloaddition reactions are described. Structures of compounds 5a-5f were supported by CIMS, FTIR, 1H, 13C, 77Se and 15N NMR spectra. The parameters of 15N and 77Se nuclei were obtained from inverse 1H-X 2D HMBC and GSQMBC correlation experiments at natural abundance. Structure of compound 5b was confirmed by X-ray analysis. The geometry of 5b was optimized by ab initio RHF/DZVP quantum chemistry calculation. A very good correlation between the calculation and experimental data was found. The geometry of 5e was optimized by ab initio DFT/VWN/DZVP quantum chemistry calculation. It was found that title compounds 5a-5f do not undergo isomerization to acylisoselenoureas, in contrast to analogous ester derivatives. Fused 6-imino-6H-1,3- selenazinium salts (chlorides 6a-6f, hydrogensulfates 7a-7f and tetrafluoroborates 8a-8f) were prepared by an acid cyclization of 5a-5f. It was found that neutralization of 6a-6f, 7a-7f and 8a-8f led to their retrocyclization to 5a-5f. Selenoureas 5a-5f with equimolar amounts of methanolic potassium hydroxide afforded potassium salts 9a-9f. Only the salts 9b, 9c, 9e and 9f of the thiophene series were isolated. Their heating in methanol solution led to deacylation of isoselenoureas 10b and 10c. The in situ prepared compounds 9a and 9d cyclized and deacylated to 4-aminoquinazoline-2-selenole 11a under the same conditions. The compounds 5a-5f and 10a-10c cyclized to fused 4-aminopyrimidine-2-selenols 11a, 11b and 4-aminopyrimidine-2-selenone 12c by boiling in methanolic potassium hydroxide solution.

Formation of Nickel Ferrite Films by Solid-State Reaction

1997 ◽  
Vol 3 (S2) ◽  
pp. 739-740
Author(s):  
Matthew T. Johnson ◽  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Solid State Reaction ◽  
Nickel Ferrite ◽  
Elevated Temperatures ◽  
Film Growth ◽  
Ex Situ ◽  
First Case ◽  
Morphological Differences

Nickel ferrite (NiFe2O4) thin films are of potential interest for magnetic applications. In the present study, the production of NiFe2O4 by solid-state reaction between thin films of hematite (α-Fe2O3) and nickel oxide (NiO) on (0001) sapphire (α-Fe2O3) substrates has been examined. The NiFe2O4 thin films were prepared by two different methods. In the first case the NiFe2O4film was grown in situ in the deposition system, while in the second case the NiFe2O4 film was formed ex situ by reacting at elevated temperatures in air. These two methods of reaction lead to interesting morphological differences in the ferrite layers.Epilayers of α-Fe2O3 followed by NiO were deposited onto (0001) α-Al2O3 by pulsed-laser deposition (PLD) in 6 mTorr O2. NiFe2O4 films were obtained by reacting the starting films in two different ways: in situ (during film growth) and ex situ.. In both cases, the α-Fe2O3 films were grown under the same conditions while those for the deposition of the NiO layers were different.

scholarly journals Factibilidad de la bipartición hepática derecha-izquierda in situ en el trasplante hepático

2019 ◽  
Vol 111 (2) ◽  
pp. 99-103
Author(s):  
H. Pablo Barros Schelotto ◽  
◽  
Luis M. Mercado ◽  
Francisco J. Pattin ◽  
Diego A. Ramisch ◽  
...  
Keyword(s):  
Liver Transplantation ◽  
Living Donor ◽  
Living Donor Liver Transplantation ◽  
Ex Situ ◽  
Donor Liver ◽  
Donor Liver Transplantation ◽  
Split Liver Transplantation ◽  
First Case ◽  
Split Liver

Due to the shortage of organs for transplantation, different surgical alternatives have been developed, as split liver transplantation (SLT) and living-donor liver transplantation. In classical SLT, the liver of a cadaveric donor is divided and two allografts are obtained, one corresponding to segments 2-3 and the other to segments 1, 4–8. In order to produce two grafts from one liver for two adult recipients, splitting of the liver can create a right graft including segments 5–8 and a left graft with segments 1–4. Splitting of the liver can be performed during procurement (in situ) or on the bench (ex situ). The aim of our study is to describe the first case of in situ full-right full-left split liver transplantation, with focus on donor and recipient surgery.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

The use of transmission and analytical electron microscopy in studying reactions and phase transformations in thin film

1993 ◽  
Vol 51 ◽  
pp. 842-843
Author(s):  
K. Barmak
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transformations ◽  
Analytical Electron Microscopy ◽  
Ex Situ ◽  
Multilayer Thin Films ◽  
Absolute Concentration ◽  
Analytical Electron ◽  
Deposition Step

Generally, processing of thin films involves several annealing steps in addition to the deposition step. During the annealing steps, diffusion, transformations and reactions take place. In this paper, examples of the use of TEM and AEM for ex situ and in situ studies of reactions and phase transformations in thin films will be presented.The ex situ studies were carried out on Nb/Al multilayer thin films annealed to different stages of reaction. Figure 1 shows a multilayer with dNb = 383 and dAl = 117 nm annealed at 750°C for 4 hours. As can be seen in the micrograph, there are four phases, Nb/Nb3-xAl/Nb2-xAl/NbAl3, present in the film at this stage of the reaction. The composition of each of the four regions marked 1-4 was obtained by EDX analysis. The absolute concentration in each region could not be determined due to the lack of thickness and geometry parameters that were required to make the necessary absorption and fluorescence corrections.

Transmission Electron Microscopy of Epitaxial silicides grown by ultra high vacuum deposition

1989 ◽  
Vol 47 ◽  
pp. 462-463
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Transmission Electron

The silicides CoSi2 and NiSi2 are both metallic with the fee flourite structure and lattice constants which are close to silicon (1.2% and 0.6% smaller at room temperature respectively) Consequently epitaxial cobalt and nickel disilicide can be grown on silicon. If these layers are formed by ultra high vacuum (UHV) deposition (also known as molecular beam epitaxy or MBE) their thickness can be controlled to within a few monolayers. Such ultrathin metal/silicon systems have many potential applications: for example electronic devices based on ballistic transport. They also provide a model system to study the properties of heterointerfaces. In this work we will discuss results obtained using in situ and ex situ transmission electron microscopy (TEM).In situ TEM is suited to the study of MBE growth for several reasons. It offers high spatial resolution and the ability to penetrate many monolayers of material. This is in contrast to the techniques which are usually employed for in situ measurements in MBE, for example low energy electron diffraction (LEED) and reflection high energy electron diffraction (RHEED), which are both sensitive to only a few monolayers at the surface.

Atomic Layer Deposition of LiF and Lithium Ion Conducting (AlF3)(LiF)x Alloys Using Trimethylaluminum, Lithium Hexamethyldisilazide and Hydrogen Fluoride

2017 ◽  
Author(s):  
Younghee Lee ◽  
Daniela M. Piper ◽  
Andrew S. Cavanagh ◽  
Matthias J. Young ◽  
Se-Hee Lee ◽  
...  
Keyword(s):  
Lithium Ion ◽  
Atomic Layer ◽  
Mass Gain ◽  
Alloy Film ◽  
Ex Situ ◽  
X Ray ◽  
Layer Deposition ◽  
Ion Conducting ◽  
Good Agreement

<div>Atomic layer deposition (ALD) of LiF and lithium ion conducting (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloys was developed using trimethylaluminum, lithium hexamethyldisilazide (LiHMDS) and hydrogen fluoride derived from HF-pyridine solution. ALD of LiF was studied using in situ quartz crystal microbalance (QCM) and in situ quadrupole mass spectrometer (QMS) at reaction temperatures between 125°C and 250°C. A mass gain per cycle of 12 ng/(cm<sup>2</sup> cycle) was obtained from QCM measurements at 150°C and decreased at higher temperatures. QMS detected FSi(CH<sub>3</sub>)<sub>3</sub> as a reaction byproduct instead of HMDS at 150°C. LiF ALD showed self-limiting behavior. Ex situ measurements using X-ray reflectivity (XRR) and spectroscopic ellipsometry (SE) showed a growth rate of 0.5-0.6 Å/cycle, in good agreement with the in situ QCM measurements.</div><div>ALD of lithium ion conducting (AlF3)(LiF)x alloys was also demonstrated using in situ QCM and in situ QMS at reaction temperatures at 150°C A mass gain per sequence of 22 ng/(cm<sup>2</sup> cycle) was obtained from QCM measurements at 150°C. Ex situ measurements using XRR and SE showed a linear growth rate of 0.9 Å/sequence, in good agreement with the in situ QCM measurements. Stoichiometry between AlF<sub>3</sub> and LiF by QCM experiment was calculated to 1:2.8. XPS showed LiF film consist of lithium and fluorine. XPS also showed (AlF<sub>3</sub>)(LiF)x alloy consists of aluminum, lithium and fluorine. Carbon, oxygen, and nitrogen impurities were both below the detection limit of XPS. Grazing incidence X-ray diffraction (GIXRD) observed that LiF and (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film have crystalline structures. Inductively coupled plasma mass spectrometry (ICP-MS) and ionic chromatography revealed atomic ratio of Li:F=1:1.1 and Al:Li:F=1:2.7: 5.4 for (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film. These atomic ratios were consistent with the calculation from QCM experiments. Finally, lithium ion conductivity (AlF<sub>3</sub>)(LiF)<sub>x</sub> alloy film was measured as σ = 7.5 × 10<sup>-6</sup> S/cm.</div>

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