nni-351 nni-351 nni-351 is an orally active inhibitor of dyrk1a and neurogenesis enhancer which is under development by neuronascent, inc. for the treatment of down syndrome, depression, and post-traumatic stress disorder (ptsd). as of 2017, it is in the preclinical development stage, and has yet to progress to human clinical trials. in july of 2022, nni-351 was granted orphan drug status by the fda for the treatment of fragile x syndrome. nni-351clinical dataroutes ofadministrationby mouthidentifiers iupac name 4-(3-cyano-6-ethoxyquinolin-2-yl)-n-(2-fluorophenyl)-1,4-diazepane-1-carbothioamide cas number929607-23-8 ypubchem cid16661882chemspider17594951unii97lg4x5p2echemical and physical dataformulac24h24fn5osmolar mass449.55 g·mol−13d model (jsmol)interactive image smiles ccoc1=cc2=c(c=c1)n=c(c(=c2)c#n)n3cccn(cc3)c(=s)nc4=cc=cc=c4f inchi inchi=1s/c24h24fn5os/c1-2-31-19-8-9-21-17(15-19)14-18(16-26)23(27-21)29-10-5-11-30(13-12-29)24(32)28-22-7-4-3-6-20(22)25/h3-4,6-9,14-15h,2,5,10-13h2,1h3,(h,28,32)key:rqxupdsafgwkmo-uhfffaoysa-n