Development of Highly Diastereo- and Enantioselective Direct Asymmetric Aldol Reaction of a Glycinate Schiff Base with Aldehydes Catalyzed by Chiral Quaternary Ammonium Salts

2004 ◽  
Vol 126 (31) ◽  
pp. 9685-9694 ◽  
Author(s):  
Takashi Ooi ◽  
Minoru Kameda ◽  
Mika Taniguchi ◽  
Keiji Maruoka
Keyword(s):  
Schiff Base ◽  
Quaternary Ammonium ◽  
Aldol Reaction ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Asymmetric Aldol ◽  
Asymmetric Aldol Reaction

New chloramphenicol Schiff base ligands for the titanium-mediated asymmetric aldol reaction of α,β-unsaturated aldehydes with diketene: a short synthesis of atorvastatin calcium

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75470-75477 ◽  
Author(s):  
Haifeng Wang ◽  
Linjie Yan ◽  
Fangjun Xiong ◽  
Yan Wu ◽  
Fener Chen
Keyword(s):  
Schiff Base ◽  
Aldol Reaction ◽  
Schiff Base Ligands ◽  
Asymmetric Aldol ◽  
Atorvastatin Calcium ◽  
Unsaturated Aldehydes ◽  
Asymmetric Aldol Reaction ◽  
Chiral Schiff Base ◽  
Short Synthesis

Several novel chiral Schiff base ligands were prepared from a commercially available chloramphenicol base and applied to the titanium-mediated asymmetric aldol reaction of diketene with various α,β-unsaturated aldehydes.

Preparation and Characterization of Two New Kinds of Soluble Quaternary Ammonium Salts of Chitosan

2011 ◽  
Vol 239-242 ◽  
pp. 496-500
Author(s):  
Li Ju Tan ◽  
He Dong Wang ◽  
Jiang Tao Wang
Keyword(s):  
Schiff Base ◽  
Ammonium Salt ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Salt ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Resonance Spectroscopy ◽  
Spectra Analysis ◽  
Chitosan Derivatives ◽  
H Nmr

Schiff base of chitosan was obtained by the reaction of chitosan and aromatic aldehyde, and then Schiff base of chitosan reacted with methyl iodide to get soluble quaternary ammonium salts of chitosan which were N-metoxybenzenemethyl quaternary ammonium salt of chitosan (NM- Chitosan) and N-hydroxybenzenemethyl quaternary ammonium salt of chitosan(NH-Chitosan). The obtained chitosan derivatives were characterized by Infrared Spectra Analysis(FT-IR), Nuclear Magnetic Resonance Spectroscopy(1H NMR) and elemental analysis. Quantitative analysis showed that there was small difference between degrees of quaternization(DQ) and degrees of substitution(DS), and the solubility of chitosan derivatives was demonstrated to be better in the organic solvents.

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