Late-Stage Microsomal Oxidation Reduces Drug–Drug Interaction and Identifies Phosphodiesterase 2A Inhibitor PF-06815189

Late-stage oxidation using liver microsomes was applied to phosphodiesterase 2 inhibitor <b>1</b> to reduce its clearance by cytochrome P450 enzymes, introduce renal clearance, and minimize the risk for victim drug–drug interactions. This approach yielded PF-06815189 (<b>2</b>) with improved physicochemical properties and a mixed metabolic profile. This example highlights the importance of C–H diversification methods to drug discovery.