aptiganel aptiganel aptiganel (cerestat; cns-1102) is an unsuccessful drug candidate which acts as a noncompetitive nmda antagonist, and that was under development by cambridge neuroscience, inc as a treatment for stroke. it has neuroprotective effects and was researched for potential use in the treatment of stroke, but despite positive results in animal studies, human trials showed limited efficacy, as well as undesirable side effects such as sedation and hallucinations, and clinical development was ultimately not continued. aptiganelclinical dataatc codenonelegal statuslegal status in general: uncontrolled identifiers iupac name 1-(3-ethylphenyl)-1-methyl-2-naphthalen-1-ylguanidine cas number137159-92-3 npubchem cid60840chemspider54827 yunii46475lv84ichemblchembl92484 ycomptox dashboard (epa)dtxsid4048432 chemical and physical dataformulac20h21n3molar mass303.409 g·mol−13d model (jsmol)interactive image smiles ccc1=cc(=cc=c1)n(c)c(=nc2=cc=cc3=cc=cc=c32)n inchi inchi=1s/c20h21n3/c1-3-15-8-6-11-17(14-15)23(2)20(21)22-19-13-7-10-16-9-4-5-12-18(16)19/h4-14h,3h2,1-2h3,(h2,21,22) ykey:bfncjmurtmzbte-uhfffaoysa-n y ny (what is this?) (verify) the drug's failure led to the collapse of cambridge neuroscience in 1998 and its eventual sale to cenes pharmaceuticals in 2000. other guanidine substances that the company had been bowling on was cns-1145 & cns1237. synthesis aptiganel synthesis: 1-naphthylamine is reacted with cyanogen bromide to give 2. treatment of this intermediate with 3-ethyl-n-methylaniline leads to addition to the cyano group and formation of the corresponding diaryl guanidine, aptiganel, 3.