R 6<NH2 H2N H2N HO OH HOT Neamine R=NH2 R R2 R3 Kanamycin A OHOH N Neomycin NH2 Paromomycin OH Kanamycin B OH NH2 NH Tobramycin H NH Amikacin OHOH HN、H NH2 OH NHR1 H2N H CHaNH OH H2N H2N HO N HO NH OH OH NHCH3 CH3 Apramyci DH HO R R H2N Gentamicin Cla H Gentamicin C1 CH3 OH Gentamicin C2 NHCH3 G418 OH