Tenofovir alafenamide Impurity 1 (Crude)

Tenofovir alafenamide Impurity 1 (Crude) is a synthetically derived byproduct arising during the alkylation step of tenofovir alafenamide production. It retains the core phosphonate ester motif of the parent drug but features an unreacted amino group at the terminal aliphatic chain, lacking the amide linkage critical for prodrug activation. The molecule exhibits a zwitterionic character due to its amidine and phosphate ester functionalities, with reduced hydrophobicity compared to the parent compound. This impurity serves as a reference standard for HPLC-based quantification of process-related alkylation inefficiencies in API batches.