52 



The Philippine Journal of Science 



IwtC 



to the knowledge of the structure of the compound. The latter 

 discussed the probability of the carboxyl group being in the para 

 position. 



Baeyer " showed the relationship to terephthalic acid and that 

 the compound must exist in the two forms 



H 



H COOEt 



0= 



=0 



Ho 



'\y' 

 /\ 



H COOEt 

 Keto. 



The latter conclusion was based upon the fact that phenylhy- 

 drazine, ammonia, and hydroxylamine react as if the compound 

 were in the keto form, while the reaction with acetyl chloride 

 (forming a diacetate) and the salt formation with alkalies indi- 

 cated the enol form. He also shows that the three representations 



H COOEt 



COOEt 

 Hzj^'SoH 



H0',^H2 

 COOEt 



COOEt 



h/^,oh 



hoMhz 

 X 



H COOEt 



H 

 HO 



H 





OH 

 H 



COOEt 



A 1.4 



^1.6 



^2.5 



are possible for the enol form.* He later prepared the derivative 





CHa 

 Ha 



COOEt 







0- 



CHa 



COOEt 









by treating the sodium compound of ethylsuccinosuccinate with 

 methyl iodide. This compound yields a mono- and a diphenyl- 

 hydrazone, as would be expected from the above representation, 

 in the same manner as does ethylsuccinosuccinate itself. 



" Ber. d. deutschen chem. Ges. (1886), 19, 428 and 1799. See also Baeyer 

 and Tutein, Ibid. (1889), 22, 2189. 

 'Ann. d. chem. (1888), 245, 190. 



