Pyridoxine Impurity B HCl

Pyridoxine Impurity B HCl is a chlorinated derivative of pyridoxine, featuring a 4-methyl-5-chloro substitution on the pyridine ring, with a protonated amine group forming the hydrochloride salt. This impurity arises via chlorination of the parent compound’s 5-position during synthetic processes, introducing a meta-directed chloro group adjacent to the hydroxymethyl substituent. Structurally, it retains the core pyridine scaffold but exhibits altered electronic properties due to chlorine’s inductive effects. Analytically, it serves as an HPLC reference standard for quantifying process-related impurities in pyridoxine APIs.