scholarly journals Enzyme-catalyzed kinetic resolution of N-Boc-trans-3-hydroxy-4-phenylpyrrolidine

2014 ◽  
Vol 12 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Ferenc Faigl ◽  
Ervin Kovács ◽  
Dóra Balogh ◽  
Tamás Holczbauer ◽  
Mátyás Czugler ◽  
...  
Keyword(s):  
Single Crystal ◽  
Absolute Configuration ◽  
Kinetic Resolution ◽  
Diffraction Method ◽  
Pure Form ◽  
X Ray Diffraction ◽  
Resolution Method ◽  
X Ray ◽  
Temperature Optimization ◽  
Acetate Derivative

AbstractThe first enzyme-catalyzed kinetic resolution of tert-butyl-3-hydroxy-4-phenylpyrrolidine-1-carboxylate is presented. Enzyme, solvent and temperature optimization resulted in a new resolution method with E = 40 enantioselectivity. The acetate derivative of the (+)-(3S,4R) enantiomer formed while the (−)-(3R,4S) isomer remained intact. Very good enantioselectivities (E > 200) were achieved in the enzyme-catalyzed alcoholysis of the racemic acetate in i-propanol and t-butanol where the (+)-(3S,4R) enantiomer was prepared in pure form (ee > 99.7%). Absolute configuration of the (−)-(3R,4S)-enantiomer was determined by single crystal X-ray diffraction method.

scholarly journals Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Durga Sankar Vavilapalli ◽  
Ambrose A. Melvin ◽  
F. Bellarmine ◽  
Ramanjaneyulu Mannam ◽  
Srihari Velaga ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Diffraction Method ◽  
Lattice Parameter ◽  
First Principle ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Principle Calculations ◽  
Photodegradation Efficiency

AbstractIdeal sillenite type Bi12FeO20 (BFO) micron sized single crystals have been successfully grown via inexpensive hydrothermal method. The refined single crystal X-ray diffraction data reveals cubic Bi12FeO20 structure with single crystal parameters. Occurrence of rare Fe4+ state is identified via X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The lattice parameter (a) and corresponding molar volume (Vm) of Bi12FeO20 have been measured in the temperature range of 30–700 °C by the X-ray diffraction method. The thermal expansion coefficient (α) 3.93 × 10–5 K−1 was calculated from the measured values of the parameters. Electronic structure and density of states are investigated by first principle calculations. Photoelectrochemical measurements on single crystals with bandgap of 2 eV reveal significant photo response. The photoactivity of as grown crystals were further investigated by degrading organic effluents such as Methylene blue (MB) and Congo red (CR) under natural sunlight. BFO showed photodegradation efficiency about 74.23% and 32.10% for degrading MB and CR respectively. Interesting morphology and microstructure of pointed spearhead like BFO crystals provide a new insight in designing and synthesizing multifunctional single crystals.

Crystal structures of (S)- and (R,S)-2,2′-bipyridine-3,3′-dicarboxylic acid 1,1′-dioxides and of their barium salts: absolute configuration and molecular distortion enforced by supramolecular self-assembly

1997 ◽  
Vol 212 (3) ◽  
Author(s):  
P. Vojtíšek ◽  
I. Císařová ◽  
J. Podlaha ◽  
Z. Žák ◽  
S. Böhm ◽  
...  
Keyword(s):  
Single Crystal ◽  
Dicarboxylic Acid ◽  
Crystal Structures ◽  
Absolute Configuration ◽  
Self Assembly ◽  
Barium Salt ◽  
X Ray Diffraction ◽  
X Ray

AbstractCrystal structures of the title compounds were determined by single crystal X-ray diffraction. Absolute configuration of the barium salt of (+)-(

scholarly journals Some experimental aspects of absolute configuration determination using single crystal X-ray diffraction

2017 ◽  
Vol 28 (10) ◽  
pp. 1330-1336 ◽  
Author(s):  
Amber L. Thompson ◽  
Sarah F. Jenkinson ◽  
George W.J. Fleet
Keyword(s):  
Single Crystal ◽  
Absolute Configuration ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Magnetically Oriented Powder Crystal to Indexing and Structure Determination

2014 ◽  
Vol 70 (a1) ◽  
pp. C1560-C1560
Author(s):  
Fumiko Kimura ◽  
Wataru Oshima ◽  
Hiroko Matsumoto ◽  
Hidehiro Uekusa ◽  
Kazuaki Aburaya ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Crystal Lattice ◽  
Powder Diffraction ◽  
Diffraction Method ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Lattice Parameters

In pharmaceutical sciences, the crystal structure is of primary importance because it influences drug efficacy. Due to difficulties of growing a large single crystal suitable for the single crystal X-ray diffraction analysis, powder diffraction method is widely used. In powder method, two-dimensional diffraction information is projected onto one dimension, which impairs the accuracy of the resulting crystal structure. To overcome this problem, we recently proposed a novel method of fabricating a magnetically oriented microcrystal array (MOMA), a composite in which microcrystals are aligned three-dimensionally in a polymer matrix. The X-ray diffraction of the MOMA is equivalent to that of the corresponding large single crystal, enabling the determination of the crystal lattice parameters and crystal structure of the embedded microcrytals.[1-3] Because we make use of the diamagnetic anisotropy of crystal, those crystals that exhibit small magnetic anisotropy do not take sufficient three-dimensional alignment. However, even for these crystals that only align uniaxially, the determination of the crystal lattice parameters can be easily made compared with the determination by powder diffraction pattern. Once these parameters are determined, crystal structure can be determined by X-ray powder diffraction method. In this paper, we demonstrate possibility of the MOMA method to assist the structure analysis through X-ray powder and single crystal diffraction methods. We applied the MOMA method to various microcrystalline powders including L-alanine, 1,3,5-triphenyl benzene, and cellobiose. The obtained MOMAs exhibited well-resolved diffraction spots, and we succeeded in determination of the crystal lattice parameters and crystal structure analysis.

The Single Crystal Vs. The Powder Method for Identification of Crystalline Materials

1976 ◽  
Vol 20 ◽  
pp. 53-62
Author(s):  
Alan D. Mighell
Keyword(s):  
Single Crystal ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Powder Method ◽  
Complex Procedure ◽  
Recent Developments ◽  
Industrial Use ◽  
Academic Laboratory

Single crystal X-ray diffraction methods for the study of crystalline materials, although reliable, have been, mainly confined to the academic laboratory because of the rather lengthy and complex procedure necessary to determine the unit cell and the space group. The situation has now changed. Several recent developments give single-crystal methods considerable potential for routine Industrial use. They Include growth of the data base, advances in lattice theory, and automation of the single-crystal X-ray diffractometer. To identify an unknown, one can start with a single crystal, mount it on the diffractometer, determine a refined primitive cell, reduce the cell, and check against a file of known reduced cells. The entire procedure can be automated. As a result, the single-crystal X-ray diffraction method can now complement the powder method for the routine analysis of crystalline materials.

Absolute configuration and domain structure of AlPO4-5 studied by single crystal X-ray diffraction

2000 ◽  
Vol 38 (2-3) ◽  
pp. 403-412 ◽  
Author(s):  
G.J Klap ◽  
H van Koningsveld ◽  
H Graafsma ◽  
A.M.M Schreurs
Keyword(s):  
Single Crystal ◽  
Domain Structure ◽  
Absolute Configuration ◽  
X Ray Diffraction ◽  
X Ray

X-ray diffraction method for determination of interplanar spacing and temperature distribution in crystals under an external temperature gradient

2015 ◽  
Vol 48 (3) ◽  
pp. 853-856 ◽  
Author(s):  
V. R. Kocharyan ◽  
A. S. Gogolev ◽  
A. E. Movsisyan ◽  
A. H. Beybutyan ◽  
S. G. Khlopuzyan ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Temperature Gradient ◽  
Single Crystal ◽  
Interplanar Spacing ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
External Temperature ◽  
X Ray ◽  
Spacing Distribution

An X-ray diffraction method is developed for the determination of the distribution of temperature and interplanar spacing in a single-crystal plate. In particular, the temperature and the interplanar spacing differences in two different parts of a quartz single crystal of X-cut are experimentally determined depending on the value of the temperature gradient applied perpendicularly to the reflecting atomic planes (10\bar 11). The temperature distribution along the direction perpendicular to the reflecting atomic planes (10\bar 11) and the interplanar spacing distribution of atomic planes (10\bar 11) are determined as well.

Single-Crystal Synthesis and Structure Refinement of Na0.44MnO2

2011 ◽  
Vol 170 ◽  
pp. 198-202 ◽  
Author(s):  
Junji Akimoto ◽  
Hiroshi Hayakawa ◽  
Norihito Kijima ◽  
Junji Awaka ◽  
Fuji Funabiki
Keyword(s):  
Single Crystal ◽  
Structure Refinement ◽  
Bond Distance ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Single Chain ◽  
X Ray ◽  
Crystal Synthesis ◽  
Manganese Valence ◽  
First Time

Single crystals of Na0.44MnO2 (=Na4Mn9O18) have been synthesized by a flux method at 1173 K for the first time. The crystal structure of Na0.44MnO2 has been refined by single-crystal X-ray diffraction method. The framework structure consists of double and triple rutile-type chains of edge-sharing MnO6 octahedra and a single chain of edge-sharing MnO5. The Mn-O bond distance and bond valence analyses revealed the manganese valence Mn3+/Mn4+ ordering in the Na0.44MnO2 structure.

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