Expanding the Scope of Cinchona Alkaloid-Catalyzed Enantioselective α-Aminations of Oxindoles: A Versatile Approach to Optically Active 3-Amino-2-oxindole Derivatives

2009 ◽  
Vol 74 (23) ◽  
pp. 8935-8938 ◽  
Author(s):  
Tommy Bui ◽  
Mar Borregan ◽  
Carlos F. Barbas
Keyword(s):  
Optically Active ◽  
Cinchona Alkaloid

Synthesis of optically active diols using an efficient polymer bound cinchona alkaloid derivative

Chirality ◽  
1995 ◽  
Vol 7 (8) ◽  
pp. 580-585 ◽  
Author(s):  
Antonella Petri ◽  
Dario Pini ◽  
Silvia Rapaccini ◽  
Piero Salvadori
Keyword(s):  
Optically Active ◽  
Cinchona Alkaloid

scholarly journals Preparation of Mesoporous SBA-16 Silica-Supported Biscinchona Alkaloid Ligand for the Asymmetric Dihydroxylation of Olefins

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Shaheen M. Sarkar ◽  
Md. Eaqub Ali ◽  
Md. Lutfor Rahman ◽  
Mashitah Mohd Yusoff
Keyword(s):  
Catalytic System ◽  
Catalyst System ◽  
Optically Active ◽  
Cinchona Alkaloid ◽  
Chiral Ligand ◽  
Asymmetric Dihydroxylation ◽  
Osmium Tetraoxide ◽  
Vicinal Diol ◽  
Ordered Mesoporous ◽  
Prepared Complex

Optically active cinchona alkaloid was anchored onto mesoporous SBA-16 silica and the as-prepared complex was used as a heterogeneous chiral ligand of osmium tetraoxide for the asymmetric dihydroxylation of olefins. The prepared catalytic system provided 90–93% yield of vicinal diol with 92–99% enantioselectivity. The ordered mesoporous SBA-16 silica was found to be a valuable support for the cinchona alkaloid liganded osmium catalyst system which is frequently used in chemical industries and research laboratories for olefin functionalization.

Diastereo- and enantioselective Mannich/cyclization cascade reaction of isocyanoacetates with cyclic sulfamide ketimines by cinchona alkaloid squaramide/AgOAc cooperative catalysis

2018 ◽  
Vol 16 (25) ◽  
pp. 4641-4649 ◽  
Author(s):  
Mei-Xin Zhao ◽  
Zhi-Wen Dong ◽  
Guang-Yu Zhu ◽  
Xiao-Li Zhao ◽  
Min Shi
Keyword(s):  
Cascade Reaction ◽  
Optically Active ◽  
Cinchona Alkaloid ◽  
Cooperative Catalysis ◽  
Mannich Cyclization

This reaction provides facile access to a variety of optically active imidazoline-fused sulfahydantoin derivatives in excellent yields and good to excellent stereoselectivities.

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.

Sign in / Sign up

Export Citation Format

Share Document