4I4H:
reference: Pyridine-Substituted Desoxyritonavir Is a More Potent Inhibitor of Cytochrome P450 3A4 than Ritonavir., Sevrioukova IF, Poulos TL, J Med Chem. 2013 Apr 26. PMID: 23586711

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).