Ethers and Esters of Nucleosides

The 0 -methyl ethers of adenosine and uridine have been prepared 

Guanosine and 2 -deoxyguanosine can be acylated in high yield on the sugar unit but not the heterocycle by use of an acid anhydride and DMAP in acetonitrile/triethyl2unine. 2 -Deoxyribonucleosides have been converted efficiently into their 5 0-aroyl derivatives by treatment in pyridine with a dilute solution of the aroyl chloride in pyridine,whilst in the rlbonucleoside series peracylated systems can be selectively unblocked at 0-2 and 0-3 in yields adsove 80% by the use of sodium methoxide in Additionally, peraroylated ribo- 

Three 3 -esters and twelve 5 -esters of 5-ethyl -2 -deoxyuri-dine have been synthesized as potential antiviral prodrugs. Host were as active as the parent compound, indicating ready hydro- 

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