Glycoside hydrolysis phosphate groups

Purine nucleotides are modified by a variety of enzymes, including those that attack the phosphate group and those that split the glycosidic bond. In addition to these, there are changes in the bases in which the amino groups of adenylic acid and guanylic acid are removed by specific deaminases. With these cases excepted (i.e., the formation of inosinic and xanthylic acids), degradation of purines occurs after hydrolysis to yield the free base. 

O-isopropylidene derivative (10) was then phosphorylated with phosphorous oxychloride to form the phosphate ester (11) from which the protecting groups were removed by mild acid hydrolysis. The 3-phos-phate (15) was obtained by phosphorylating the 4,6-benzylidene derivative (13) of the same glycoside with phosphorus oxychloride, followed by hydrolytic removal of the protecting groups, from the ester (14) thus obtained. 

---