PURDIE'S REACTION 191 



methyl alcohol are removed and two compounds are obtained 

 which are both inactive and neither of which contain methoxyl. 

 These are 2:2:5: 5-tetraphenyl-2 : 5-dihydrofuran : 



CH.CPh 2V 



II >0 



CH . CPh/ 



and a triphenylbutyrolactone respectively. The same furan 

 derivative is obtained by the action of magnesium phenyl 

 bromide on methyl maleate. 



PREPARATION OF DIALKYLOXY-DERIVATIVES OF 

 SUCCINIC ACID 



The first compound of this type to be synthesised by means 

 of the silver oxide reaction was ethyl d-diethoxysuccinate, 

 prepared by Purdie and Pitkeathly (1). The production of 

 methyl rf-dimethoxysuccinate from methyl tartrate by Purdie 

 and Irvine (8) has already been described ; from ethyl tartrate, 

 by treatment with silver oxide and methyl iodide, the same 

 authors prepared ethyl rf-dimethoxysuccinate. The crystalline 

 rf-dimethoxysuccinic acid is obtained from either of the 

 methoxy-esters by hydrolysis with barium hydroxide, and 

 subsequent decomposition of the barium salt by sulphuric 

 acid. A number of normal and hydrogen-metallic salts of 

 d-dimethoxysuccinic acid were prepared, and the determina- 

 tion of the rotation of these, and of the esters mentioned 

 above, furnished material from which certain generalisations 

 on the optical activity of this series of compounds could be 

 drawn. d-Dimethoxysuccinamide was also prepared, but 

 attempts to convert this into the corresponding imide, like 

 other attempts made at a later date, were fruitless. 



The work on the optical activity of methyl-, ethyl-, and 

 propyl-dimethoxysuccinates was continued by Purdie and 

 Barbour (9), who traced the influence of solvents on the 



