Chemical modification of aminoglycosides. 3. Synthesis of 2"-deoxykanamycins from neamine

The preparation of 2"-deoxykanamycin B (12) and 2",3',4'-trideoxykanamycin B (14) from neamine (1) is described. Key intermediates in the synthesis of these 2"-deoxyaminoglycoside antibiotics are 3',4'-bis-O-(p-nitrobenzoyl)-1,2',3,6'-tetrakis-N-(trifluoroacetyl)neamine (6) and 3',4'-dideoxy-1,2',3,6'-tetrakis-N-(trifluoroacetyl)neamine (9). The amino groups of these intermediates are blocked by the trifluoroacetyl group, a blocking group not widely used in aminoglycoside chemistry.