Absolute configuration of eremophilane sesquiterpenes fromPetasites hybridus: Comparison of experimental and calculated circular dichroism spectra

Chirality ◽  
2009 ◽  
pp. NA-NA ◽  
Author(s):  
Antje Bodensieck ◽  
Walter M.F. Fabian ◽  
Olaf Kunert ◽  
Ferdinand Belaj ◽  
Sajid Jahangir ◽  
...  
2013 ◽  
Vol 69 (11) ◽  
pp. 1411-1413 ◽  
Author(s):  
Yuko Kawanami ◽  
Hidekazu Tanaka ◽  
Jun-ichi Mizoguchi ◽  
Nobuko Kanehisa ◽  
Gaku Fukuhara ◽  
...  

The absolute configuration has been established of the enantiopureanti-head-to-head cyclodimer of anthracene-2-carboxylic acid (AC) cocrystallized with L-propinol and dichloromethane [systematic name: (S)-2-(hydroxymethyl)pyrrolidin-1-ium (5R,6S,11R,12S)-8-carboxy-5,6,11,12-tetrahydro-5,12:6,11-bis([1,2]benzeno)dibenzo[a,e][8]annulene-2-carboxylate dichloromethane monosolvate], C5H12NO+·C30H19O4−·CH2Cl2. In the crystal structure, the AC dimer interacts with L-prolinol through a nine-membered hydrogen-bonded ring [R22(9)], while the dichloromethane molecule is incorporated to fill the void space. The absolute configuration determined in this study verifies a recent assignment made by comparing theoreticalversusexperimental circular dichroism spectra.


1980 ◽  
Vol 45 (2) ◽  
pp. 435-441 ◽  
Author(s):  
Jan Pospíšek ◽  
Štefan Toma ◽  
Ivo Frič ◽  
Karel Bláha

Racemic 3-ferrocenylalanine was resolved in enantiomers using brucine. The absolute configuration was estimated by ozonolytic degradation of the N-trifluoroacetyl derivative of the (-)-enantiomer yielding D-aspartic acid. Diastereoisomeric cyclo(D-ferrocenylalanyl-L-prolyl) and cyclo-(L-3-ferrocenylalanyl-L-prolyl) were synthesized using conventional methods of peptide synthesis. Circular dichroism spectra of these cyclodipeptides are discussed and compared with spectra of the corresponding diastereoisomeric cyclodipeptides containing phenylalanine.


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