| abstract |
Processes for preparing 2′-O-alkylated guanosine, uridine, cytidine, and 2,6-diaminopurine 3′-O-phosphoramidites include the steps of alkylating nucleoside precursors, adding suitable blocking groups and phosphitylating. For the guanosine 2′-O-alkylated 3′-O-phosphoramidites, alkylation is effected on 2,6-diamino-9-(β-D-ribofuranosyl) purine followed by deamination. For uridine 2′-O-alkylated 3′-O-phosphoramidites, alkylation is effect on a dialkyl stannylene derivative of uridine. For cytidine 2′-O-alkylated 3′-O-phosphoramidites, alkylation is effected directly on cytidine. Alkylation is effected directly upon 2,6-diaminopurine. |