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| Pyrazole | Pyrazoline | Pyrazolidine |
This is a yellow food coloring pyrazole derivative.
The oxidation of pyrazoline produces pyrazolones:
The pyrazol-3-ones and some of their derivatives have remarkable antipyretic properties
1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one
First antipyretic and analgesic drug. No longer used because of significant contraindications.
4-Dimethylamino-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one is an antipyretic analgesic medicament and more effective than antipyrine. Is now rarely used because of significant contraindications. Is replaced by the propyphenazone (4-isopropyl-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one) more harmless, where the $N$ atom of the dimethylamino group is replaced by a $C$ atom :
