Practical Synthesis from Streptomycin and Regioselective Partial Deprotections of (-)-(1,2,3,4,5,6)-1,3-Di(deamino)-1,3-diazido-2,5,6-tri--benzylstreptamine.

We describe the gram-scale synthesis of (-)-(1,2,3,4,5,6)-1,3-di(diamino)-1,3-diazido-2,5,6-tri--benzylstreptamine from streptomycin by (i) hydrolysis of the two streptomycin guanidine residues, (ii) reprotection of the amines as azides, (iii) protection of all alcohols as benzyl ethers, and (iv) glycosidic bond cleavage with HCl in methanol. Protocols for regioselective monodebenzylation and regioselective reduction of a single azide in the product are also described, providing four optically pure building blocks for exploitation in novel aminoglycoside synthesis.