S,X-acetals in nucleoside chemistry. III. Synthesis of 2 '- and 3 '-O-azidomethyl derivatives of ribonucleosides

2'- and 3'-O-azidomethyl derivatives of ribonucleosides were obtained by splitting the corresponding methylthiomethyl derivatives of ribonucleosides with bromine or SO2Cl2 followed by lithium azide treatment.