2CL5:
reference: Comparative study of ortho- and meta-nitrated inhibitors of catechol-O-methyltransferase: interactions with the active site and regioselectivity of O-methylation., Palma PN, Rodrigues ML, Archer M, Bonifacio MJ, Loureiro AI, Learmonth DA, Carrondo MA, Soares-da-Silva P, Mol Pharmacol. 2006 Jul;70(1):143-53. Epub 2006 Apr 17. PMID: 16618795

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