n-POC-POC tenofovir

n-POC-POC tenofovir is a diphosphonate derivative of tenofovir, featuring two phosphonyloxycyclopropyl (POC) moieties appended to the parent nucleoside backbone via phosphodiester linkages. The structure incorporates a bis-phosphonate functional group, with each POC unit comprising a cyclopropyl ring conjugated to a phosphoryl oxygen. This impurity arises from aberrant coupling during synthetic phosphitylation steps, resulting in dual phosphonate substitution at the terminal hydroxyl of the tenofovir prodrug scaffold. The compound retains the 9-(2-phosphonylmethoxypropyl) adenine core but exhibits altered hydrophilicity and chromatographic behavior. It serves as an HPLC reference standard for quantifying process-related impurities in tenofovir alafenamide formulations.