| Abstract: | 13C-NMR. spectra of pterin, xanthopterin, isoxanthopterin, leucopterin, lumazine and of the model compounds isocytosine and desamino-isocytosine have been measured as anions and cations in 1 M NaOD, CF3COOH, H2SO4 and FSO3H solutions. The spectra were analysed by means of heteronuclear double resonance, with the aid of non-decoupled spectra, and by spectral comparison. The results are interpreted in terms of the ionisation state of the pteridines in the four solvents and are compared with those obtained from 1H-NMR. spectroscopy. |
