230 Royal Society ; — 



a series of salts which have the general formula 



C 8 H,M0 3 , 

 and into two substitution-products, 



s H,BrO 3 

 and 



C 8 H 7 I0 3) 



both of which had previously been prepared by Carles from the 

 natural compound. 



In order further to elucidate the nature of vanilline, we have sub- 

 mitted this body to fusion with alkali. The product of this action 

 is a well-known acid discovered by Streeker, and described by 

 him as protocatechuic acid, 



0,H,O 4 , 

 which is thus formed — 



C 8 H 8 3 + 40 = C 7 H e 4 + H 2 + C0 2 . 

 We have identified this substance by analysis, by the study 

 of its. reactions, and also by transforming it into pyrocatechine, 

 C 6 H e 2) 



C 7 H e 4 = C 6 H 6 2 + C0 2 . 

 The transformation into protocatechuic acid fixes the constitu- 

 tion of vanilline. This compound is the methylated aldehyde of 

 protocatechuic acid ; its composition referred to benzol is repre- 

 sented by the formula 



/OCH 3 

 C 6 H 3 fOH 

 \COH. 

 Indeed, submitted under pressure to the action of hydrochloric 

 acid, vanilline splits into chloride of methyl and protocatechuic 

 aldehyde, 



/OCH 3 7 0H 



C 6 H 3 fOH +HCl=CH 3 Cl + C 6 H a ^-OH 

 \COH \COH. 



A corresponding action takes place with hydriodic acid ; but in 

 this case the aldehyde is destroyed. 



An additional proof of the correctness of our view regarding the 

 constitution of vanilline is obtained by treating this substance with 

 acetic anhydride and benzoyl chloride. 



The action does not go beyond the formation of the compounds 



och 3 



C,H ) f0C 1 H ! 



and 



yOOH, 



C 9 H 3 ^OC T H.O 



\COH, 



