1H‐ und 13C‐NMR‐Spektren von N‐Methyl‐chinoliniumchalkonen: Bestimmung von σ‐Konstanten für die 2‐, 3‐ und 4‐Position des N‐Methyl‐chinoliniumrings

Abstract

1H‐ and 13C‐N.M.R. Spectra of N‐Methyl‐quinolinium Chalcones: Determination of σ‐Constants for the 2‐, 3‐ and 4‐Position of the N‐Methyl‐quinolinium RingFor the N‐methyl‐quinolinium chalcones 1a–c the 1H‐ and 13C‐n.m.r. data are reported. The unambiguous assignment of signals is based upon the 1H/1H homoshift and the 13C/1H heteroshift correlated 2D‐n.m.r. spectra. Using a Hammett relationship we have determined σ‐constants for the 2‐, 3‐ and 4‐position of the N‐methyl‐quinolinium ring from the 13C‐α chemical shifts of 1a–c. Their comparison with the σ‐values for the equivalent positions in the pyridine, N‐methyl‐pyridinium and quinoline ring indicates the additivity of anellation and quaternization effect.