ANTIPYRINE (phenyldimethyl pyrazolone) (C11H12N20), is prepared by the condensation of phenylhydrazine with acetoacetic ester, the resulting phenyl methyl pyrazolone being heated with methyl iodide and methyl alcohol to loo-110° C.: CH 0=N CH3 C-N CH3 >N C6H5 - II >N C6H6 CH 2 -CO HC-CO Phenyl methyl pyrazolone Antipyrine On the large scale phenylhydrazine is dissolved in dilute sulphuric acid, the solution warmed to about 40° C. and the aceto-acetic ester added.
The benzene layer on evaporation deposits the antipyrine as a colourless crystalline solid which melts at 113° C. and is soluble in water.
In medicine antipyrine ("phenazonum") has been used as an analgesic and antipyretic. The dose is 5-20 grs., but on account of its depressant action on the heart, and the toxic effects to which it occasionally gives rise, it is now but little used.
(saloquinine); and of the soluble substitutes, quinopyrine (a compound of quinine hydrochloride and antipyrine) and quinine hydrochlorocarbamide (a compound of quinine, urea and hydrochloric acid).
In addition to dyestuffs, it is a starting-product for the manufacture of many drugs, such as antipyrine, antifebrin, &c. Aniline is manufactured by reducing nitrobenzene with iron and hydrochloric acid and steam-distilling the product.