34 



The Philippine Journal of Science 



1913 



The analogies existing between methyl salicylate and aceto- 

 acetic ether are very striking. The chemical relationships have 

 been pointed out by Freer, 4 and determinations of the affinity 

 constants of the acids and the hydrolysis constants of their 

 sodium salts show the former to be of the magnitude 10- 11 and 

 the latter 0.001 in each case. 



The expressions suggested by Hantzsch 5 for the valence isom- 







CH 3 C/\ Me 



HC :o 

 C- OC 2 H 5 







CH 3 C/\Me 



HC 



C- OC2H5 



erism in the aci-salt in explanation of the absorption band in 

 acetoacetic ether can be applied to methyl salicylate, the cor- 

 responding form showing the conjugated linking being: 







/\/\Me 







//\//--Me 







c 



\ 



OCH3 



c 



\ 







0CH3 



There is no doubt that methyl salicylate in the presence of 

 alkali behaves very differently from the other phenolic com- 

 pounds discussed in this paper. 



Phenol, o-cresol, salicylate acid, and o-hydroxybenzyl alcohol 

 in the presence of alkali show a reduction in the persistence of 

 the characteristic absorption band (discussed later), while aceto- 

 acetic ether shows no band in the absence of alkali, but develops 

 a characteristic band which increases in persistence with the in- 

 creasing concentration of alkali salt. Methyl salicylate shows 

 no appreciable change in the persistence of its band with alkali, 

 the effect of increasing concentration of the latter being to 

 shift the band toward the red. If the intramolecular vibration 

 producing this band is to be attributed to the conjugated linking 

 as above represented, it is clear that an excess of alkali has 



* Am. Chem. Journ. (1892), 14, 407. 



°Ber. d. deutschen chem. Ges. (1910), 43, 3053. 



