AbstractThe vicinal13C1H,15N1H and13C15N spin coupling constants were obtained from the1H and13C NMR spectra of various ionic forms of the amino acids phenylalanine, α‐aminobutyric acid and β‐alanine, and also from their15N isotopomers. It is concluded that the13C1H and15N1H coupling constants are reliable parameters for conformational studies of amino acids, whereas the practical applicability of the13C15N constants for the same pu