Studies on a selena-aza-crown ether: Synthesis and catalytic behavior in hydrosilylation

1997 ◽  
Vol 2 (4) ◽  
pp. 464-466 ◽  
Author(s):  
Xu Wei ◽  
Liu Xiufang ◽  
Lu Xueran ◽  
Xu Hansheng
Keyword(s):  
Crown Ether ◽  
Catalytic Behavior ◽  
Ether Synthesis ◽  
Aza Crown Ether

Polycarboxylate crown ethers from meso-tartaric acid

1991 ◽  
Vol 69 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Frank R. Fronczek ◽  
Richard D. Gandour ◽  
Thomas M. Fyles ◽  
Philippa J. Hocking ◽  
Susan J. McDermid ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crown Ether ◽  
Tartaric Acid ◽  
Crown Ethers ◽  
Nmr Spectra ◽  
Product Distribution ◽  
Complexing Agents ◽  
Triclinic Space Group ◽  
The Stability ◽  
Ether Synthesis

The synthesis of crown ethers derived from meso-tartaric acid was investigated. The sodium salt of the bis(dimethylamide) of meso-tartaric acid reacted with diethylene glycol ditosylate to give a mixture of 18-crown-6 tetraamide and 27-crown-9 hexaamide crown ethers. The 2R,3S,11S,12R 18-crown-6 isomer crystallized in triclinic space group [Formula: see text] (a = 7.557(2), b = 8.866(2), c = 10.4133(13) Å, α = 94.13(2), β = 95.86(2), γ = 99.26(2)°, R = 0.040 for 2090 observed of 3129 unique reflections). The structures of the remaining products were then assigned from the NMR spectra. The solution conformations of the amide crown ethers were examined by NMR, and provide a rationale for the product distribution obtained. One of the 18-crown-6 isomers and a mixture of the two 27-crown-9 isomers were hydrolyzed to the respective crown ether carboxylic acids, and the stability constants for complexation of cations were determined by potentiometric titration. The meso tetra- and hexacarboxylates are remarkably nonselective and inefficient cation complexing agents, compared to related crown ethers from R,R-(+)-tartaric acid, due to the unfavorable conformational control exerted by the tartaro units. Key words: crown ether synthesis, complexation, crown ether conformation, meso-tartaric acid, crystal structure.

Complexation and transport of amino acid esters and their salts with synthesised chiral novel aza crown ether derivatives

2013 ◽  
Vol 26 (5-6) ◽  
pp. 363-372 ◽  
Author(s):  
Mehmet Kazaylek ◽  
Şafak Ozhan Kocakaya ◽  
Elif Varhan Oral ◽  
Mehmet Çolak ◽  
Mehmet Karakaplan
Keyword(s):  
Amino Acid ◽  
Crown Ether ◽  
Amino Acid Esters ◽  
Acid Esters ◽  
Aza Crown Ether
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