OP ARTS AND SCIENCES. 123 



vanillin, but also that it was one of the principal products of the oxi- 

 dation. For this purpose we first tried to make acetylcurcumiu by 

 treating curcumin with acetylchloride : this gave a deep biuish-greeu 

 liquid, which on standing turned brown, and then yielded on addition 

 of water a yellowish precipitate which could not be obtained in crys- 

 tals, its solutions forming on evaporation a dark-colored varnibh. 

 With acetic anhydride no better results were obtained, and as there 

 seemed no prospect of getting a good analysis of the substance, it 

 was at once oxidized with potassic permauyanate. The result was nut 

 essentially better than that obtained with pure curcumin, and we 

 accordingly turned our attention to the oxidation of diethylcurcumiii, 

 which was made by boiling the dipotassic salt with absolute alcohol 

 and a slight excess of cthyliodide for six hours in a flask with a 

 return cooler. On distilling off part of the alcohol and allowing the 

 rest to evaporate spontaneously, the compound is left as a most unin- 

 viting brownish-black tar, which when heated with sodic hydrate dis- 

 solves with a dark red color resembling that of the alkaline solution 

 of curcumin. Upon treating this solution with potassic permanganate 

 until -it was decolorized, filtering from manganic hydrate, and acidify- 

 ing with sulphuric acid, a yellowish precipitate was obtained, which 

 after two crystallizations from boiling water with bone-black melted at 

 195°, the melting-point given by Wassermann* for ethylvanillic acid 

 (Tiemanu t gives 193°-194°). 



The nature of the substance was still further confirmed by the fol- 

 lowing combustion : — 



0.1216 gr. of substance gave 0.2714 gr. of CO^ and 0.0707 gr. of 



up. 



Calculated for C10H12O4 Found. 



Carbon 61.22 60.87 



Hydrogen . 6.12 6.46 



There can be no doubt, therefore, that the substance is ethylvanillic 

 acid, and it was formed in such quantity that it must be considered one 

 of the principal products of the reaction. If the potassic permanga- 

 nate was not added in excess, and the liquid extracted with ether, 

 crystals of ethylvanillin were obtained, which on sublimation formed 

 an oil solidifying after a short time in large twinned crystals Hke those 



* Ann. Cliom. Plmrm. 179, p. 366. 

 t Ber. d. ch. G. 1875. p 1127. 



