Synthesis of 5-deoxy-5-epifluoro derivatives of arbekacin, amikacin and 1-N-tobramycin (study on structure - toxicity relationships)

Article abstract of DOI:10.1016/0008-6215(95)00123-B

As part of a study on fluorination-toxicity relationships for aminoglycoside antibiotics, 5,3'-dideoxy-5-epifluorokanamycin B (10), 5,3',4'-trideoxy-5-epifluorokanamycin B (11), 1-N-<(S)-4-amino-2-hydroxybutanoyl>-5-deoxy-5-epifluorotobramycin (19), 5-deoxy-5-epifluoroarbekacin (20), and 5-deoxy-5-epifluoroamikacin (21) have been prepared.The acute toxicities of these three 5-deoxy-5-epifluoro compounds showed values almost identical or similar to those for arbekacin (ABK) and amikacin (15), making a sharp contrast with the toxicities of the corresponding 5-deoxy-5-fluoro derivatives.This fact is explained on the basis of basicity changes (retention for the 5-epifluoro derivatives and reduction for the 5-fluoro derivatives) at the H2N-3 groups of the fluorinated compounds compared to the parent compounds; this hypothesis was substantiated by the pKa values at the H3N¹⁺-1,3-groups (determined by the shift changes depending on pD values at C-2 and C-4, 6 in their 13C NMR spectra) of 2,5-dideoxy-5-epifluorostreptamine (23) and 2,5-dideoxy-5-fluorostreptamine (24), chosen as model compounds, and 2-deoxystreptamine (DST). Keywords: Arbekacin; Amikacin; 1-N-<(S)-4-Amino-2-hydroxybutanoyl)tobramycin