Synthesis of Photodegradation Impurities from Venlafaxine Hydrochloride

OBJECTIVE To perform the quality control of the bicyclic atypical antidepressant venlafaxine hydrochloride bulk medicine, the venlafaxine hydrochloride photodegradable impurities I2-cyclohexylidene-2-(4-methoxyphenyl)-N,Ndimethylethanamine was prepared. METHODS Through condensation reaction of p-methoxyphenylacetonitrile and cyclohexanone, LiAlH₄ reduction reaction, formic acid/formaldehyde double methylation reaction, photodegradable impurities I was obtained. RESULTS The structures of impurities I were confirmed by ¹H-NMR, ¹³C-NMR, MS, and the HPLC indicated that the purity of product was higher than 99.0%. CONCLUSION The impurities I can be used as impurity reference for quality control of venlafaxine hydrochloride active pharmaceutical ingredient.