Umespirone

Umespirone is a drug of the azapirone class which possesses anxiolytic and antipsychotic properties. It behaves as a 5-HT_1A receptor partial agonist, D₂ receptor partial agonist, and α₁-adrenoceptor receptor antagonist, and also has weak affinity for the sigma receptor. Unlike many other anxiolytics and antipsychotics, umespirone produces minimal sedation, cognitive/memory impairment, catalepsy, and extrapyramidal symptoms.

Synthesis

The condensation between ethyl cyanoacetate and acetone gives ethylisopropylidenecyanoacetate . This product is reacted with N-butylcyanoacetamide in sodium methoxide solution to give N-butyl-2,4-dicyano-3,3-dimethylglutarimide, . The glutarimide is cyclized with phosphoric acid to yield 3-butyl-9,9-dimethyl-3,7-diazabicyclononane-2,4,6,8-tetraone, https://pubchem.ncbi.nlm.nih.gov/compound/10825633 CID:10825633.
The reaction between 1-piperazine and 1,4-dibromobutane gives the Quat salt .
Convergent synthesis affords .