z4349 z4349 z4349 is an opioid analgesic drug developed in the 1990s by the pharmaceutical company zambon. it is a derivative of an older drug viminol, which has been modified to improve potency and metabolic stability. in tests on mice it was found to be several hundred times the potency of morphine. z4349identifiers iupac name (5s)-5-amino]-1-hydroxyethyl]-1-(2-chlorobenzyl)pyrrolidin-2-one pubchem cid10317679chemspider8493143chemical and physical dataformulac21h33cln2o2molar mass380.96 g·mol−13d model (jsmol)interactive image smiles cc(c)n(c(1ccc(=o)n1cc2=cc=cc=c2cl)o)(c)cc inchi inchi=1s/c21h33cln2o2/c1-5-15(3)23(16(4)6-2)14-20(25)19-11-12-21(26)24(19)13-17-9-7-8-10-18(17)22/h7-10,15-16,19-20,25h,5-6,11-14h2,1-4h3/t15-,16-,19+,20+/m1/s1key:yngzjsalrclelm-ykcbxccjsa-n