An Efficient Synthesis of 3′‐Amino‐3′‐deoxyguanosine from Guanosine

3′-Amino-3′-deoxyguanosine was synthesized from guanosine in eight steps and 58% overall yield. The 2′,3′-diol of 5′-O-[(tert-butyl)diphenylsilyl]-2-N-[(dimethylamino)methylidene]guanosine was reacted with α-acetoxyisobutyryl bromide and treated with 0.5n NH3 in MeOH to yield 9-{2′-O-acetyl-3′-bromo-5′-O-[(tert-butyl)diphenylsilyl]-3′-deoxy-β-D-xylofuranosyl]-2-N-[(dimethylamino)methylidene]guanine, which was reacted with benzyl isocyanate, NaH, and then 3.0n NaOH, and finally with Pd/C (10%) and HCO2NH4 in EtOH/AcOH to afford 3′-amino-3′-deoxyguanosine.