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Diastereomers of 3‐( S )‐(1‐phenylethyl)‐5‐methyl‐ and ‐5‐phenylrhodanine: Crystal structures, conformations, and circular dichroism spectra
Author(s) -
Rang Knut,
Liao FenLing,
Sandström Jan,
Wang SueLein
Publication year - 1997
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/(sici)1520-636x(1997)9:5/6<568::aid-chir26>3.0.co;2-l
Subject(s) - diastereomer , chemistry , chirality (physics) , epimer , circular dichroism , cndo/2 , substituent , crystallography , stereochemistry , spectral line , vibrational circular dichroism , crystal structure , axial chirality , enantiomer , cotton effect , molecule , chiral symmetry , organic chemistry , catalysis , enantioselective synthesis , physics , quantum mechanics , astronomy , nambu–jona lasinio model , quark
3‐( S )‐(1‐phenylethyl)‐5‐methyl‐ and 5‐phenyl‐rhodanine have been studied by single crystal X‐ray crystallography. The crystals of the 5‐methyl compound were shown to contain equal amounts of the 5‐( R ) and 5‐( S ) diastereomers, while the crystals of the 5‐phenyl compound only contain the 5‐( S ) diastereomer. The UV and CD spectra of the 5‐H 2 compound have been analyzed on the basis of CNDO/S calculations, and the CD spectrum has been reproduced by semiempirical calculations. The 5‐methyl diastereomers can be partly separated by chromatography on triacetylcellulose, and the CD spectra of the individual forms can be evaluated. The 5‐phenyl compound undergoes rapid epimerization in solution, and also for this compound the CD spectra of both forms can be evaluated. The contribution of the 5‐substituent follows Ripperger's sector rule for dithiocarbamates. Chirality 9:568–577, 1997. © 1997 Wiley‐Liss, Inc.