Structural and conformational analysis of 2-triphenylphosphoranylidene succinic acid derivatives by1H,13C and31P one and two dimensional NMR spectroscopy and molecular modelling

1995 ◽  
pp. 965-972 ◽  
Author(s):  
Radu Bacaloglu ◽  
Andrei Blaskó ◽  
Clifford A. Bunton ◽  
Giorgio Cerichelli ◽  
Fernando Castaneda ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Conformational Analysis ◽  
Succinic Acid ◽  
Molecular Modelling ◽  
Two Dimensional

scholarly journals NMR Investigation and Conformational Analysis of a Synthetic Hexasaccharide

1995 ◽  
Vol 50 (7) ◽  
pp. 1091-1095
Author(s):  
Monika Hiegemann ◽  
Helmut Duddeck ◽  
Richard R. Schmidt ◽  
Alexander Toepfer
Keyword(s):  
Nmr Spectroscopy ◽  
Conformational Analysis ◽  
Spectroscopic Investigation ◽  
Two Dimensional

The structure of the hexasaccharide 1 has been examined by a spectroscopic investigation using one- and two-dimensional NMR spectroscopy All 1H and 13C signals of the saccharide part were assigned. NOESY and ROESY experiments allowed to discuss the flexibility of the molecule.

scholarly journals Structure and conformational analysis of spiroketals from 6-O-methyl-9(E)-hydroxyiminoerythronolide A

2015 ◽  
Vol 11 ◽  
pp. 1447-1457 ◽  
Author(s):  
Ana Čikoš ◽  
Irena Ćaleta ◽  
Dinko Žiher ◽  
Mark B Vine ◽  
Ivaylo J Elenkov ◽  
...  
Keyword(s):  
Double Bond ◽  
Nmr Spectroscopy ◽  
Conformational Analysis ◽  
Reaction Kinetics ◽  
Molecular Modelling ◽  
Lactone Ring ◽  
Facile Synthesis ◽  
One Pot ◽  
Unexpected Formation ◽  
Spontaneous Change

Three novel spiroketals were prepared by a one-pot transformation of 6-O-methyl-9(E)-hydroxyiminoerythronolide A. We present the formation of a [4.5]spiroketal moiety within the macrolide lactone ring, but also the unexpected formation of a 10-C=11-C double bond and spontaneous change of stereochemistry at position 8-C. As a result, a thermodynamically stable structure was obtained. The structures of two new diastereomeric, unsaturated spiroketals, their configurations and conformations, were determined by means of NMR spectroscopy and molecular modelling. The reaction kinetics and mechanistic aspects of this transformation are discussed. These rearrangements provide a facile synthesis of novel macrolide scaffolds.

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