PURDIE'S REACTION 215 



ALKYLATION OF OTHER TAUTOMERIC COMPOUNDS 



In his general investigation of the applicability of the 

 silver oxide reaction (4) Lander tested the action of silver 

 oxide and ethyl iodide on ethyl acetoacetate for the purpose 

 of preparing, if possible, the isomeric ether in place of the 

 alkyl compound formed by the action of sodium ethoxide and 

 ethyl iodide. That is to say, it was hoped that ethyl aceto- 

 acetate would react in the enolic form as ethyl /3-hydroxy- 

 crotonate and so be converted into ethyl /?-ethoxycrotonate 

 CH 3 . C(OC 2 H 5 ) : CH . COOC 2 H 5 . The product of the reaction 

 was fractionally distilled, and thus separated into the two 

 substances ethyl ethylacetoacetate and ethyl /?-ethoxy- 

 crotonate. As might perhaps have been expected, the yield of 

 the latter was very small (5 per cent.). The simultaneous pro- 

 duction of . OC 2 H 5 and C . C 2 H 5 derivatives of ethyl aceto- 

 acetate may be regarded as evidence of the existence of both 

 ketonic and enolic forms in the original substance. The fact 

 that the product is largely composed of the ketonic derivative 

 agrees with the physical evidence that ethyl acetoacetate 

 exists, under ordinary conditions, mainly in the ketonic form. 



When benzoylacetic ester is treated with the same reagents, 

 the course of the reaction is entirely similar to that shown by 

 acetoacetic ester, the alkylated product consisting very largely 

 of the C-ethyl homologue C 6 H 5 .CO.CHEt.COOEt mixed with 

 very small quantities of the isomeric ^8-ethoxycinnamic ester, 

 C 6 H 5 . C(OEt) : CH . COOEt (Lander (10) ). It would appear 

 from these results that the silver oxide reaction, unlike the 

 usual method of alkylating tautomeric substances of this type 

 by which C-ethers only are obtained, does not interfere with 

 the equilibrium between the dynamic isomerides of which the 

 parent substance is composed. 



Alkylation of ethyl ethylacetoacetate only occurred to a 

 very slight extent (4) in an experiment carried out under 



