

Pyrimidine is a 6-membered ring consisting of four carbon atoms and two nitrogen centers at the 1- and 3- ring positions.

These are polycyclic aromatic compounds containing a benzene ring linked to a pyrimidine ring through a CC or CN bond.

Zaleplon also binds selectively to the brain omega-1 receptor located on the alpha subunit of the GABA-A/chloride ion channel receptor complex and potentiates t-butyl-bicyclophosphorothionate (TBPS) binding. Zaleplon exerts its action through subunit modulation of the GABA BZ receptor chloride channel macromolecular complex. Zaleplon also binds selectively to the CNS GABA A-receptor chloride ionophore complex at benzodiazepine(BZ) omega-1 (BZ1, ο1) receptors.

Subunit modulation of the GABA BZ receptor chloride channel macromolecular complex is hypothesized to be responsible for some of the pharmacological properties of benzodiazepines, which include sedative, anxiolytic, muscle relaxant, and anticonvulsive effects in animal models. While Zaleplon is a hypnotic agent with a chemical structure unrelated to benzodiazepines, barbiturates, or other drugs with known hypnotic properties, it interacts with the gamma-aminobutyric acid-benzodiazepine (GABA BZ) receptor complex. Zaleplon is a nonbenzodiazepine hypnotic from the pyrazolopyrimidine class and is indicated for the short-term treatment of insomnia.
