576 SCIENCE PROGRESS 



latter may be regarded as a complex substance of the acetic 

 acid series, interact to give rise to a compound containing 

 a new ring in the manner indicated in the following diagram : 



CijHs C6H5 



j^ ; H O . C2H5 : j^ 



/ " I ■ / \ 



N^H.;: CO -> N CO + C.H5.OH + H.,0 



I ■; I II I " 



CHj.CjO^ CH2 CH3.C CH2 



XII. 



This product, phenylmethylpyrazolone (XII.), is physio- 

 logically inert, but on methylation (treatment with methyl 

 iodide) it gives rise to phenyldimethylpyrazolone (XIII.) or 

 antipyrine. 



C,H5 CHs 



N N 



x\ / \ 



CH3.N CO CH3.N CO 



II II 



CH3.C — CH CH3.C— C.NCCHs), 



XIII. XIV. 



This compound is a valuable antipyretic and antineuralgic ; 

 it reduces febrile temperatures to the normal, and the subse- 

 quent rise of temperature is gradual and unaccompanied by 

 shivering fits. The reduction of temperature is maintained 

 for eight to twenty hours. 



Knorr's good fortune in synthesising a therapeutic agent 

 of this order is gauged by the fact that although many other 

 derivatives of the pyrazolone series have been prepared and 

 patented as antipyretics, only one has shown itself to be of 

 anything like the same value as antipyrine. The drug in question 

 is the substance pyraniidon, which has been placed on the market 

 by the firm of Meister, Lucius & Briining, who were also the 

 first to prepare Knorr's antipyrine on a manufacturing scale. 

 Pyramidon, dimethylamino-antipyrine (formula XIV.) is prepared 

 by treating antipj'rine with nitrous acid, reducing the resulting 

 nitroso-antipyrine to amino-antipyrine and then finally methy- 

 lating this base to obtain the required compound. This drug 

 is thrice as active as antipyrine ; its action begins more 

 gradually and continues for a much longer time. It is prescribed 

 in rheumatism, influenza, and t3^phoid fever ; it forms salts with 



