(S)-Desmethylnaproxen

(S)-Desmethylnaproxen is the desmethyl derivative of (S)-naproxen, featuring a hydroxyl group substituted at the 6-position of the naphthalene ring in place of the methoxy moiety. It retains the (S)-configuration at the α-methyl chiral center and maintains the propionic acid functionality characteristic of the parent compound. This structural modification results in a polar impurity arising from synthetic pathways or oxidative degradation during naproxen production. It serves as a critical HPLC reference standard for quantifying process-related impurities in naproxen APIs.