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Spectroscopic studies and PM3 semiempirical calculations of Schiff bases of gossypol with L ‐amino acid methyl esters
Author(s) -
Przybylski Piotr,
Brzezinski Bogumil
Publication year - 2002
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.10043
Subject(s) - chemistry , diastereomer , gossypol , epimer , hydrogen bond , schiff base , tautomer , enamine , nuclear magnetic resonance spectroscopy , carbon 13 nmr , stereochemistry , proton nmr , medicinal chemistry , organic chemistry , molecule , catalysis , biochemistry
Three Schiff bases of racemic gossypol with L ‐amino acid methyl esters are synthesized and studied by FTIR and 1 H‐NMR spectroscopy, and their structures are calculated by the PM3 semiempirical method. The Schiff bases in the study exist in the solid state and in solutions as enamine forms. The existence of diastereoisomers is very visible in the 1 H‐NMR spectra. The amount of the diastereoisomers depends on the amount of time the solutions are rested in diffused light. The epimerization from D , L ‐isomer to L , L ‐isomer is very slow. The structures of the Schiff bases and the hydrogen bonds within these structures are discussed. © 2002 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 67: 61–69, 2002; DOI 10.1002/bip.10043