daclatasvir Acetyl impurity

Daclatasvir Acetyl impurity is a synthetic byproduct formed via acetylation of a primary amine in the parent NS5A inhibitor daclatasvir, introducing an acetyl (CH₃CO−) moiety at the 4-position of the piperazine ring. This modification replaces a labile hydrogen with an acetyl group, forming an amide linkage and increasing steric bulk. The compound retains the core benzothiazole and triazole scaffolds of daclatasvir but exhibits altered polarity due to the acetyl substitution. Its structural similarity enables competitive inhibition in HPLC analysis. It serves as an HPLC reference standard for quantifying acetylated impurities in daclatasvir drug substance.