Aminoglycoside antibiotics. 2. N,N-Dialkylkanamycins

N6',N3''-Dialkyl derivatives of kanamycins A and B were prepared regiospecifically from the parent antibiotics. Although the dimethyl and diethyl derivatives of kanamycin A were inactive in standard antibacterial assays, the dimethyl derivative of kanamycin B showed moderate activity, especially against various strains of Pseudomonas aeruginosa. A method for the selective dimethylation of the 3''-amino group of kanamycin A also was developed.