<unk> , a five-membered-ring lactam, is a derivative of pyrazole that has an additional keto (=O) group.
It has a molecular formula of C3H4N2O.
Examples of derivatives include:
Ampyrone
Metamizole
Phenazone
Phenylbutazone
Pyrazolone
Enoxolone
Fluorometholone
Tibolone
Quinbolone
Carbenoxolone
Oxymetholone
Sulfathiazole