Lm. Beauchamp et al., GUANINE, PYRAZOLO[3,4-D] PYRIMIDINE, AND TRIAZOLO[4,5-D] PYRIMIDINE (8-AZAGUANINE) PHOSPHONATE ACYCLIC DERIVATIVES AS INHIBITORS OF PURINE NUCLEOSIDE PHOSPHORYLASE, Journal of medicinal chemistry, 39(4), 1996, pp. 949-956
Phosphonate acyclic derivatives of guanines, pyrazolo[3,4-d]pyrimidine
s, and triazolo[4,5-d]-pyrimidines (8-azaguanines) are inhibitors of t
he enzyme purine nucleoside phosphorylase (PNPase) with K-i' values ra
nging from 0.05 to 1.6 mu M. These compounds are enzymatically stable
congeners of the potent PNPase inhibitor acyclovir diphosphate (53).