Complete 1H and 13C NMR Assignments for Apramycin, Sisomicin and Some N- and N,O-Polyacetylated Aminoglycosides

Article abstract of DOI:10.1002/mrc.1260300908

The 1H NMR spectra (300 MHz) of the aminoglycoside antibiotics apramycin and sisomicin (free bases) were completely analysed by 1D and 2D methods (mainly 1H-1H and 1H-13C shift-correlation spectroscopy).The complete 1H and 13C NMR assignment of a series of semisynthetic N-polyacetyl- and N,O-polyacetyl derivatives of kanamycins A and B, tobramycin, apramycin and sisomicin was also achieved via these techniques.The effect of acetylation on the 1H and 13C chemical shifts, 1H-1H coupling constants and ring conformations is discussed.The vicinal coupling constants for the unsaturated ring in sisomicin, calculated on the basis of the energetically favoured conformation predicted by the MMP2 method, are in good agreement with the experimental data. KEY WORDS: Aminoglycoside antibiotics; 1H NMR; 13C NMR; Acetylation shifts; Ring conformations