Applicability of vicinal heteronuclear (¹³C‐¹H, ¹⁵N‐¹H, ¹³C‐¹⁵N) coupling constants for conformational analysis of amino acids: Phenylalanine, α‐aminobutyric acid and β‐alanine

The vicinal 13 C 1 H, 15 N 1 H and 13 C 15 N spin coupling constants were obtained from the 1 H and 13 C NMR spectra of various ionic forms of the amino acids phenylalanine, α‐aminobutyric acid and β‐alanine, and also from their 15 N isotopomers. It is concluded that the 13 C 1 H and 15 N 1 H coupling constants are reliable parameters for conformational studies of amino acids, whereas the practical applicability of the 13 C 15 N constants for the same purpose is doubtful.