Melting point: 109-111℃ (lit.)
Boiling point: 319℃
Density: 1,19 g/cm3
Refractive index: 1.5850 (estimate)
This product is an antipyretic and analgesic drug, which has strong antipyretic, analgesic, anti-inflammatory and anti rheumatic effects. However, due to the serious adverse reactions, the clinical application has been gradually reduced, and some of the old varieties have been gradually eliminated. Antipyrine is an analytical reagent. It is used for the analysis of nitric acid, nitrite and iodine, the determination of elements forming complex cation, and the gravimetric determination of titanium.
It is obtained by methylation and hydrolysis of 1-phenyl-3-methylpyrazolone - 5. In the dry methylation tank, add pyrazolone, then add dimethyl sulfate, raise the temperature to 160 ℃, react for 6h, and heat the water to boil for 2h. Put the methylated reactant into a hydrolysis tank containing sodium hydroxide solution, and stir it for hydrolysis at 100-110 ℃ for 3h. Leave it still for layering, place the antipyrine oil layer in the crystallizing tank, dilute it with distilled water, stir it, cool it to below 10 ℃, precipitate crystals, filter it, wash it, and dry it to obtain crude antipyrine. The crude product is recrystallized with distilled water and decolorized with activated carbon to obtain the finished product. Methyl chloride or methyl bromide can also be used as raw materials for methylation operation, and such methylation reagents can be used as methanol solution to stir reaction with 1-naphthyl-3-methylpyridinone in a small amount. Then the methanol is evaporated, the reactant is dissolved in water, made slightly alkaline with sodium hydroxide, and antipyrine is extracted with benzene, recrystallized from benzene, and finally refined with active carbon and water recrystallized. Another method is to use equimolar N, N-phenylmethylhydrazine and ethyl acetoacetate to heat and reflux on an oil bath at 130-160 ℃. Antipyrine is extracted from thick oily liquid with boiling water, and then evaporated to remove water to obtain crystals.