PURDIE'S REACTION 183 



materials used. A further instance was noted by Purdie and 

 the writer (58), who found that the two hydroxyl groups of 

 yS - dimethoxy - fie - dimethylhexane - /3e - diol HO. C (CH 3 ) 2 .CH 

 (OCH 3 ).CH(OCH 3 ).C(CH 3 ) 2 .OH resisted alkylation by this 

 method. 



As regards phenolic hydroxyl groups data are lacking, since 

 experiments do not appear to have been made on the simple 

 phenols. With certain substituted phenols, however, alkyla- 

 tion of the phenolic group occurred readily. Thus Irvine 

 (5 and 11) prepared salicylaldehyde methyl ether in 90 per 

 cent, yield by the action of silver oxide and methyl iodide on 

 salicylaldehyde. Practically no oxidation of the aldehyde 

 occurred, since only a trace of methyl o-methoxybenzoate was 

 found in the product. Similarly Lander (4) prepared the 

 latter ester directly from salicylic acid. The phenolic ethers 

 so obtained were free from resinous matter, such as is generally 

 produced during the preparation of these substances by the 

 aid of alkyl iodides and caustic potash. On the other hand, 

 Meldola and Kuntzer (52) obtained a negative result with a 

 substituted phenol. 



Although the silver oxide reaction finds its chief applica- 

 tion in the alkylation of hydroxyl groups, yet, as Lander has 

 shown (4, 6, 7, 13, 21, and 24), it is possible by its aid to 

 substitute alkyl radicles for hydrogen in the molecules of 

 amides and substituted amides. In this way imino-ethers 

 may be prepared. An account of the results which have been 

 obtained in this direction is given later. 



METHODS OF APPLYING THE REACTION 



It is important that the silver oxide used should be freshly 

 prepared and carefully dried. The oxide is most conveniently 

 prepared by adding hot, filtered barium hydroxide solution to 

 a hot solution of silver nitrate, washing the precipitated oxide 

 with boiling water until all excess of barium hydroxide has 



