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Updated: Apr 21, 2026

Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Axial chirality of 4-arylpyrazolo[3,4-b]pyridines. Conformational analysis and absolute configuration
Pethaiah Gunasekaran1, Subbu Perumal, J Carlos Menéndez
1Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University , Madurai 625 021, Tamil Nadu, India.
Abstract:
The stereodynamic behavior of a series of pyrazolo[3,4-b]pyridines was studied. The restricted rotations of the aryl substituent in position 4 of the heteroaromatic ring and of the benzoyl group in position 5 generated conformational enantiomers or conformational diastereoisomers depending on the local symmetry of the aryl substituent, with very high rotational barriers despite the absence of ortho-substituents. The energy barriers for the rotation of the 5-benzoyl group and the 4-aromatic ring were measured by dynamic NMR and rationalized by DFT calculations. When the aryl substituent at position 4 was 1-naphthyl, the resulting atropisomeric pair was resolved by means of enantioselective HPLC and the absolute configuration was determined by TD-DFT simulations of electronic circular dichroism spectra.
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