above the adenine amine protecting group acetyl or benzoyl is then cleaved by treatment of the derived nucleoside with methanolic ammonia which conditions will also cleave any ester protecting group on the sugar hydroxyls when b represents guanine silylated 2 acetylamino 9h purin 6 yl diphenylcarbamate may be used as the nucleophile and the coupling reaction is carried out using the persilylation conditions of vorbr u00fcggen above the guanine amine and hydroxyl protecting groups acetyl and diphenylaminocarbonyl respectively are then cleaved by treatment of the derived nucleoside with methanolic ammonia or hydrazine hydrate which conditions will also cleave any ester protecting group on the sugar hydroxyls representative experimental procedures utilizing the novel process of the present invention are detailed below the following examples are provided for purposes of illustration only and are not intended to limit the process of the present invention to the specific conditions for making the compound by halogen is meant fluorine chlorine bromine or iodine by u201c phth u201d is meant phthaloyl the u201c squiggly u201d bond at the anomeric position of the furanose ring in the intermediate of structural formula iii is intended to signify undefined stereochemistry at this stereogenic center thus the process of the present invention is intended to encompass the individual u03b1 and u03b2 anomers of the intermediate of structural formula iii as well as all mixtures thereof as starting materials for the instant process all x ray patterns were obtained on a philips 3100 diffractometer using cu k u03b1 radiation from 2 u00b0 to 40 u00b0 2 u03b8 using a collection time of 8 min all dsc thermograms were taken on a ta 2920 differential scanning calorimeter with a heating rate of 10 u00b0 c.