Intramolecular C-H⋯O hydrogen bonding in 1,4-dihydropyridine derivatives

The diastereotopy of the methylene protons at positions 2 and 6 in 1,4-dihydropiridine derivatives with various substituents has been investigated. NMR spectroscopy and quantum chemistry calculations show that the CH⋯O intramolecular hydrogen bond is one of the factors amplifying the chemical shift differences in the 1H-NMR spectra.Peer reviewe