| 摘要 |
<p>Disclosed are methods for selectively derivatizing the 2'-hydroxyl group of partially protected cytosine ribonucleosides having unprotected 2' and 3'-hydroxyl groups. The partially protected cytosine ribonucleoside is reacted with a hydrocarbon halide in the presence of a metal salt catalyst, such as silver (I) oxide, and less than one, preferably less than one half, equivalent of base. Preferably, starting material is selected to produce the partially protected 2'-O-derivatized cytosine ribonucleoside product which is suitable for direct conversion to a cytosine RNA synthon. Also disclosed is a method for deaminating partially protected 2'-O-derivatized cytidine ribonucelosides to prepare the corresponding partially protected 2'-O-derivatized uridine ribonucleosides. According to the method, the partially protected 2'-O-derivatized cytidine ribonucleoside starting material is reacted with a hydroxide source in an aqueous solution containing miscible organic solvent at elevated temperatures. Preferably, the starting material is selected to produce the partially protected 2'-O-derivatized uridine ribonucleoside suitable for direct conversion to a uridine RNA synthon.</p> |
