Synthesis of xanthosine 2-phosphate diesters via phosphitylation of the carbonyl group.

O2-Phosphodiesterification of xanthosine has been achieved by a one-pot procedure consisting of the phosphitylation of the 2-carbonyl group of appropriately protected xanthosine derivatives using phosphoramidites and N-(cyanomethyl)dimethylammonium triflate (CMMT), oxidation of the resulting xanthosine 2-phosphite triesters, and deprotection. In addition, a study on the hydrolytic stability of a fully deprotected xanthosine 2-phosphate diester has revealed that it is more stable at higher pH.