7-Chloro-4-(piperazin-1-yl)quinolone is an important scaffold in medicinal chemistry, exhibiting diverse pharmacological profiles either alone or as a hybrid with other active pharmacophores.

2-Oxo-6-phenyl-1,2,3,6-tetrahydro-pyrimidine-4-carboxylic acid belonging to the pyrimidine family, which has been shown to have anti-inflammatory, anticonvulsant and antitumor properties.

PZM21 is an effective and selective μ opioid receptor agonist (EC50: 1.8 nM).