Synthesis of optically active piperidine and pyrrolidine alkaloids from L-lysine, L-ornithine, or L-proline using anodic oxidation as key steps

1986 ◽  
Vol 51 (13) ◽  
pp. 2590-2592 ◽  
Author(s):  
Tatsuya Shono ◽  
Yoshihiro Matsumura ◽  
Kenji Tsubata ◽  
Kenshi Uchida
Keyword(s):  
Anodic Oxidation ◽  
Optically Active ◽  
Key Steps ◽  
Pyrrolidine Alkaloids

Synthesis of optically active 1-(2-furyl)-3-pentanol. A simple route to (2S, 5R/S)-chalcogran

1990 ◽  
Vol 55 (5) ◽  
pp. 1234-1242 ◽  
Author(s):  
Eva Körblová ◽  
Bohumír Koutek ◽  
David Šaman ◽  
Aleš Svatoš ◽  
Petr Maloň ◽  
...  
Keyword(s):  
Pancreatic Lipase ◽  
Optically Active ◽  
Baker’S Yeast ◽  
Enantioselective Synthesis ◽  
Biologically Active ◽  
Unsaturated Ketone ◽  
Baker's Yeast ◽  
Simple Route ◽  
Key Steps

Enantioselective synthesis of the title alcohol VI is reported, which utilizes either pig pancreatic lipase mediated transesterification or a reduction with baker's yeast at the key steps. The transesterification of VI gives (S)-(+)-VI (e.e. 80%) or (R)-(-)-V (e.e. 50%), while the reduction of the corresponding α,β-unsaturated ketone IV affords (R)-(-)-VI (e.e. 30%). These intermediates allowed to prepare a mixture of chalcogran I diastereoisomers containing 54% of the biologically active (2S, 5R) isomer.

An efficient synthesis of an optically active (-)-(3R, 4R, 5R)-4-(1-hydroxyl-isopropyl)-3-acetyloxyl-butyrolactone

2005 ◽  
Vol 2005 (10) ◽  
pp. 665-668 ◽  
Author(s):  
JinXin Wang ◽  
ChaoXin Zhang ◽  
Ying Li ◽  
QiDong You
Keyword(s):  
Crystal Structure ◽  
Optically Active ◽  
Reductive Cleavage ◽  
Starting Material ◽  
Asymmetric Epoxidation ◽  
Efficient Synthesis ◽  
Cleavage Reaction ◽  
X Ray ◽  
Key Steps ◽  
Sharpless Asymmetric Epoxidation

An optically active β-hydroxyl–γ-butyrolactone was synthesised from nonchiral starting material by employing reductive cleavage reaction, Sharpless asymmetric epoxidation and dihydroxylation as key steps. This strategy can be used to prepare many chiral β-hydroxyl–γ-butyrolactone analogues. The crystal structure of 10 was determined by X-ray crystallographs.

Reflections on the Cognitive Interviewing Reporting Framework

Methodology ◽  
2013 ◽  
Vol 9 (3) ◽  
pp. 123-128 ◽  
Author(s):  
Gordon Willis ◽  
Hennie Boeije
Keyword(s):  
Research Design ◽  
Cognitive Testing ◽  
Level Of Detail ◽  
Cognitive Interviewing ◽  
Research Groups ◽  
Research Project ◽  
Reporting Framework ◽  
Full Explanation ◽  
Key Steps

Based on the experiences of three research groups using and evaluating the Cognitive Interviewing Reporting Framework (CIRF), we draw conclusions about the utility of the CIRF as a guide to creating cognitive testing reports. Authors generally found the CIRF checklist to be usable, and that it led to a more complete description of key steps involved. However, despite the explicit direction by the CIRF to include a full explanation of major steps and features (e.g., research objectives and research design), the three cognitive testing reports tended to simply state what was done, without further justification. Authors varied in their judgments concerning whether the CIRF requires the appropriate level of detail. Overall, we believe that current cognitive interviewing practice will benefit from including, within cognitive testing reports, the 10 categories of information specified by the CIRF. Future use of the CIRF may serve to direct the overall research project from the start, and to further the goal of evaluation of specific cognitive interviewing procedures.

Optical analysis of ink and other contaminants in process waters

TAPPI Journal ◽  
2012 ◽  
Vol 11 (8) ◽  
pp. 51-58
Author(s):  
ANTTI HAAPALA ◽  
MIKA KÖRKKÖ ◽  
ELISA KOIVURANTA ◽  
JOUKO NIINIMÄKI
Keyword(s):  
Optically Active ◽  
Process Water ◽  
Paper Machine ◽  
Optical Analysis ◽  
Direct Process ◽  
Active Components ◽  
Water Contaminants ◽  
Dependent Measurement ◽  
Measurement Methodology

Analysis methods developed specifically to determine the presence of ink and other optically active components in paper machine white waters or other process effluents are not available. It is generally more interest¬ing to quantify the effect of circulation water contaminants on end products. This study compares optical techniques to quantify the dirt in process water by two methods for test media preparation and measurement: direct process water filtration on a membrane foil and low-grammage sheet formation. The results show that ink content values obtained from various analyses cannot be directly compared because of fundamental issues involving test media preparation and the varied methodologies used to formulate the results, which may be based on different sets of assumptions. The use of brightness, luminosity, and reflectance and the role of scattering measurements as a part of ink content analysis are discussed, along with fine materials retention and measurement media selection. The study concludes with practical tips for case-dependent measurement methodology selection.

Microscopic Structure of Er-Related Optically Active Centers in Si

2003 ◽  
Vol 770 ◽  
Author(s):  
H. Przybylinska ◽  
N. Q. Vinh ◽  
B.A. Andreev ◽  
Z. F. Krasil'nik ◽  
T. Gregorkiewicz
Keyword(s):  
Ground State ◽  
Photoluminescence Spectrum ◽  
Zeeman Effect ◽  
Optically Active ◽  
Single Type ◽  
Active Centers ◽  
Mbe Growth ◽  
Spectral Components ◽  
Er Doped ◽  
Successful Observation

AbstractA successful observation and analysis of the Zeeman effect on the near 1.54 μm photoluminescence spectrum in Er-doped crystalline MBE-grown silicon are reported. A clearly resolved splitting of 5 major spectral components was observed in magnetic fields up to 5.5 T. Based on the analysis of the data the symmetry of the dominant optically active center was conclusively established as orthorhombic I (C2v), with g‼≈18.4 and g⊥≈0 in the ground state. The fact that g⊥≈0 explains why EPR detection of Er-related optically active centers in silicon may be difficult. Preferential generation of a single type of an optically active Er-related center in MBE growth confirmed in this study is essential for photonic applications of Si:Er.

The development of alternative energy sources: Prospects in Russia and the world

2020 ◽  
Vol 16 (5) ◽  
pp. 885-904
Author(s):  
M.E. Frai
Keyword(s):  
Alternative Energy ◽  
Systems Approach ◽  
Energy Resource ◽  
Current Situation ◽  
Energy Sources ◽  
The Sustainable Development ◽  
Energy Complex ◽  
Alternative Energy Sources ◽  
Governmental Institutions ◽  
Key Steps

Subject. The article discusses limited sources of energy nowadays and an ongoing survey of new ones. I focus on fuel and energy complexes worldwide and in Russia. Objectives. The study is to analyze the future use of alternative energy sources in the fuel and energy complex nationwide and worldwide. I review the existing energy sources of the fuel and energy complex in the global and regional markets, specifically the alternative ones. Methods. The study relies upon methods of statistics, analysis and systems approach. Results. The article demonstrates that the fuel and energy complex strongly depends on the current situation in the energy resource market, which is difficult to forecast. If we continue relying on traditional energy resources, we get exposed to some risks affecting the sustainable development of the economy. Russia should diversify the power engineering sector by developing alternative energy sources. The article sets forth the economic rationale for alternative sources and key steps Russia shall make. Conclusions and Relevance. Considering the current situation in the energy balance, alternative energy is what any advanced society seeks for, being supported by manufacturers, governmental institutions, and researchers, though low profitability and high infrastructure costs impede its development. In Russia, these challenges are even more palpable. However, even now Russia is able to find alternative energy solutions. In addition to advantages of alternative energy, which is globally proclaimed, they will also help Russia diversify and update the economic system.

CO2 Activation on Heterostructures of Bi2O3-Nanocluster Modified TiO2: Promoting the Critical First Step in CO2 Conversion

2018 ◽  
Author(s):  
Michael Nolan
Keyword(s):  
Metal Oxide ◽  
Density Functional ◽  
Initial Step ◽  
Difficult Problem ◽  
Carbonate Formation ◽  
Structural Distortions ◽  
Strong Adsorption ◽  
Two Factors ◽  
Key Steps ◽  
Recent Experimental Work

The conversion of CO<sub>2</sub> to fuels is of significant importance in enabling the production of sustainable fuels, contributing to alleviating greenhouse gas emissions. While there are a number of key steps required to convert CO<sub>2</sub>, the initial step of adsorption and activation by the catalyst is critical. Well-known metal oxides such as oxidised TiO<sub>2</sub> or CeO<sub>2</sub> are unable to promote this step. In addressing this difficult problem, recent experimental work shows the potential for bismuth-containing materials to activate and convert CO<sub>2</sub>, but the origin of this activity is not yet clear. Additionally, nanostructures can show enhanced activity towards CO<sub>2</sub>. In this paper we present density functional theory (DFT) simulations of CO<sub>2</sub> activation on heterostructured materials composed of extended rutile and anatase TiO<sub>2</sub> surfaces modified with nanoclusters with Bi<sub>2</sub>O<sub>3</sub> stoichiometry. These heterostructures show low coordinated Bi sites in the nanoclusters and a valence band edge that is dominated by Bi-O states. These two factors mean that supported Bi<sub>2</sub>O<sub>3</sub> nanoclusters are able to adsorb and activate CO<sub>2</sub>. Computed adsorption energies lie in the range of -0.54 eV to -1.01 eV. In these strong adsorption modes, CO<sub>2</sub> is activated, in which the molecule bends giving O-C-O angles of 126 - 130<sup>o</sup> and elongation of C-O distances up to 1.28 Å, with no carbonate formation. The electronic properties show a strong CO<sub>2</sub>-Bi-oxygen interaction that drives the interaction of CO<sub>2</sub> to induce the structural distortions. Bi<sub>2</sub>O<sub>3</sub>-TiO<sub>2</sub> heterostructures can be reduced to form Bi<sup>2+</sup> and Ti<sup>3+</sup> species. The interaction of CO<sub>2</sub> with this electron-rich, reduced system can produce CO directly, reoxidising the heterostructure or form an activated carboxyl species (CO<sub>2</sub><sup>-</sup>) through electron transfer from the heterostructure to CO<sub>2</sub>. These results highlight that a semiconducting metal oxide modified with suitable metal oxide nanoclusters can activate CO<sub>2</sub>, thus overcoming the difficulties associated with the difficult first step in CO<sub>2</sub> conversion.

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