ndtdi ndtdi ndtdi is a tricyclic tryptamine derivative which is thought to act as a serotonin receptor agonist, though its pharmacology has not been studied in detail. it is a structurally simplified analogue of lsd and is reported to retain similar effects, though with many times lower potency. it has been sold as a designer drug since 2016 and was first identified by a forensic laboratory in slovenia in 2017. ndtdilegal statuslegal status illegal in latvia identifiers iupac name n,n-diethyl-3-(methyl(1,3,4,5-tetrahydrobenzoindol-4-yl)amino)propanamide chemical and physical dataformulac19h27n3omolar mass313.445 g·mol−13d model (jsmol)interactive image smiles ccn(cc)c(=o)ccn(c)c1cc3cccc2ncc(c1)c23 legality ndtdi was made illegal in latvia in march 2017.