4Y2B:
reference: 2-(Isopropylamino)thieno[3,2-d]pyrimidin-4(3H)-one derivatives as selective phosphodiesterase 7 inhibitors with potent in vivo efficacy., Endo Y, Kawai K, Asano T, Amano S, Asanuma Y, Sawada K, Onodera Y, Ueo N, Takahashi N, Sonoda Y, Kamei N, Irie T, Bioorg Med Chem Lett. 2015 May 1;25(9):1910-4. doi: 10.1016/j.bmcl.2015.03.031., Epub 2015 Mar 20. PMID: 25866242

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