Synthesis of aminotrideoxybutirosin A, a chemically modified antibiotic active against butirosin-resistant bacteria.

5"-Amino-3',4'5"-trideoxybutirosin A (4) was synthesized by two routes starting from the known tri-O-acetyl-tetra-N-benzyloxycarbonyl-3",5"-O-cyclohexylidene-3',4'-di-O-mesylbutirosin A (5). Introduction of amino function at C-5" was carried out by displacement of 5"-tosyloxy group with sodium azide either before or after 3',4'-deoxygenation. Compound 4 shows outstanding activities against strains including Pseudomonas aeruginosa and Escherichia coli which are highly resistant to butirosin and 5"-amino-5"-deoxybutirosin A (2).