Nordoxepin HCl

Nordoxepin HCl is a tricyclic amine derivative featuring a dibenzoheptane core with a terminal aroylamine moiety, where the tertiary amine is protonated as the hydrochloride salt. It constitutes a positional isomer of doxepin, lacking a methyl group at the cycloheptene ring's 10-position, thereby altering its lipophilicity and metabolic stability. This compound arises as a synthetic byproduct during the dealkylation of doxepin under acidic conditions, characterized by its distinct UV absorption maxima at 254 nm. It serves as an HPLC reference standard for quantifying process-related impurities in Nordoxepin formulations.