1. Problem: Oxidative Degradation of High-Value Pharmaceutical Intermediates Pharmaceutical intermediates — including 6-APA (6-aminopenicillanic acid, the penicillin precursor), 7-ACA (7-aminocephalosporanic acid), and various statin intermediates — are acutely sensitive to oxygen and moisture. These molecules contain oxidation-prone functional groups (amines, thiols, conjugated double bonds) that react with atmospheric oxygen through autoxidation mechanisms, forming