Vilazidone PIP amino amide impurity

Vilazidone PIP amino amide impurity is a structurally related synthetic byproduct formed during the coupling of the pyridinylpiperazine (PIP) moiety with the dibenzofuran scaffold of Vilazidone. It features an amino amide linkage between the PIP piperazine nitrogen and a terminal acyl group, substituting the native aryl-oxygen bridge. This impurity retains the 3-(4-(4-(2-pyridinyl)piperazin-1-yl)butyl)phenol core but incorporates an N-acyl-piperazine side chain, altering hydrogen bonding and hydrophobic interactions. It arises from non-regioselective amidation during API synthesis, competing with the intended etherification step. This compound serves as an HPLC reference standard for impurity profiling in Vilazidone drug substance analysis.