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Updated: May 27, 2026

Nucleoside Triphosphates - From Synthesis to Biochemical Characterization
Published on: April 3, 2014
Structure of cyclic nucleoside phosphonate ester prodrugs: an inquiry
Ivan S Krylov1, Valeria M Zakharova, Michaela Serpi
1Department of Chemistry, University of Southern California, Los Angeles, California 90089-0744, United States.
None:
The configuration at phosphorus in cyclic (S)-HPMPC (1, cidofovir) and (S)-HPMPA (2) phenyl ester (5 and 6, respectively) diastereomers ((R(p))-5, (R(p))-6, (S(p))-6) was determined by X-ray crystallography and correlated to their (1)H and (31)P NMR spectra in solution. (R(p))-5 and (R(p))-6 have chair conformations with the nucleobase substituent equatorial and the P-OPh axial. Perhaps surprisingly, (S(p))-6 is (a, a) in the crystal and exists largely as an equilibrium of (a, a)/(e, e) conformers in chloroform or acetonitrile.
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