Improved synthesis of 2′-amino-2′-deoxyguanosine and its phosphoramidite

2′-Amino-2′-deoxynucleosides and oligonucleotides containing them have proven highly effective for an array of biochemical applications. The guanosine analogue and its phosphoramidite derivatives have been accessed previously from 2′-amino-2′-deoxyuridine by transglycosylation, but with limited overall efficiency and convenience. Using simple modifications of known reaction types, we have developed useful protocols to obtain 2′-amino-2′-deoxyguanosine and two of its phosphoramidite derivatives with greater convenience, fewer steps, and higher yields than reported previously. These phosphoramidites provide effective synthons for the incorporation of 2′-amino-2′-deoxyguanosine into oligonucleotides.