PURDIE'S REACTION 211 



tion, furan derivatives are produced, and oxidation products 

 further contaminate the alkyl ethers formed and render 

 purification difficult. For further details illustrating the 

 advantage of the employment of the silver oxide reaction in 

 this direction, the original paper should be consulted. A 

 modification of the usual procedure of alkylation was used 

 by these authors in the methylation of furoin by the silver 

 oxide method, and should be noted. The sparing solubility 

 of this compound in methyl iodide and its ready oxidation to 

 furil rendered the usual methods unavailable. Furoin methyl 

 ether was, however, obtained by adding silver oxide to a 

 solution of furoin in ethyl acetate to which had been added the 

 requisite quantity of methyl iodide and also sufficient dry ether 

 to reduce the boiling-point of the solution to 50 C. 



Optically active benzoin has now been obtained by 

 McKenzie and Wren (Trans., 1908, 93, 310), who prepared 

 Z-benzoin by the action of magnesium phenyl bromide on 

 Z-mandelamide. Wren (48) has since prepared a number of 

 derivatives of Z-benzoin, among them being the methyl 

 ether. The method of alkylation by silver oxide and methyl 

 iodide was utilised for this preparation in preference to the 

 other method as being less likely to yield a racemised product ; 

 further, Fischer's method has been shown to yield a quantity 

 of by-products (vide supra). Z-Benzoin methyl ether was 

 readily prepared by the method indicated, and is remarkable 

 for the extraordinary influence of solvents on the rotation 

 of the substance ; the specific rotation varies from -88*2 

 (chloroform) to 147'8 (heptane). 



In attempting to prepare Z-benzoin ethyl ether by Fischer's 

 method, Wren (49) found that complete racemisation occurred. 

 Z-Benzoin and alcoholic hydrogen chloride therefore interact 

 to form r-benzoin ethyl ether. On ethylating Z-benzoin by 

 the silver oxide process, a partially racemised product was 

 obtained, and it is very probable that the racemisation did 

 not occur during the alkylation process but during the vacuum 



