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.

[1] It has neuroprotective effects and was researched for potential use in the treatment of stroke,[2] but despite positive results in animal studies,[3] human trials showed limited efficacy,[4] as well as undesirable side effects such as sedation and hallucinations,[5][6] and clinical development was ultimately not continued.

[7] The drug's failure led to the collapse of Cambridge Neuroscience in 1998[8] and its eventual sale to CeNeS Pharmaceuticals in 2000.

[9] Other guanidine substances that the company had been bowling on was Cns-1145 & CNS1237.

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.