abt-239 abt-239 abt-239 is an h3-receptor inverse agonist developed by abbott. it has stimulant and nootropic effects, and has been investigated as a treatment for adhd, alzheimer's disease, and schizophrenia. abt-239 is more active at the human h3 receptor than comparable agents such as thioperamide, ciproxifan, and cipralisant. it was ultimately dropped from human trials after showing the dangerous cardiac side effect of qt prolongation, but is still widely used in animal research into h3 antagonists / inverse agonists. abt-239identifiers iupac name 4-(2--benzofuran-5-yl)benzonitrile cas number460746-46-7 460746-51-4 (racemic)460749-29-5 (s-isomer)pubchem cid9818903iuphar/bps1218chemspider7994652 yunii86h6b395pichemblchembl351231 ycomptox dashboard (epa)dtxsid00196710 chemical and physical dataformulac22h22n2omolar mass330.431 g·mol−13d model (jsmol)interactive image smiles n#cc1=cc=c(c2=cc3=c(c=c2)oc(ccn4(ccc4)c)=c3)c=c1 inchi inchi=1s/c22h22n2o/c1-16-3-2-11-24(16)12-10-21-14-20-13-19(8-9-22(20)25-21)18-6-4-17(15-23)5-7-18/h4-9,13-14,16h,2-3,10-12h2,1h3/t16-/m1/s1 ykey:kfhyzkcrxnrkrc-mrxnpfedsa-n y (verify)