Exploring 8189. To explore a different substance…

N-{1-[3-(tert-Butylamino)-3-oxopropyl]piperidin-4-yl}-N-phenylpropanamide
 8189  C21H33N3O2  359.506
 Fentanyl
 InChI=1S/C21H33N3O2/c1-5-20(26)24(17-9-7-6-8-10-17)18-11-14-23(15-12-18)16-13-19(25)22-21(2,3)4/h6-10,18H,5,11-16H2,1-4H3,(H,22,25)
 OYWPBLBSTQLWKP-UHFFFAOYSA-N This stereoisomer Any stereoisomer
 CCC(=O)N(c1ccccc1)C1CCN(CC1)CCC(=O)NC(C)(C)C