Ryan and Ebrill — llie S//nthesis of Ghjcmides. o83 



Owing to its stability, it is even more convenient than the crystallized 

 acetobromoglucose of Koenigs and Knorr ; and the method of prepa- 

 ration is simpler than that of Fischer and Armstrong for the aceto- 

 halogenhexoses. 



Action of Methyl Alcohol on Acetochloroarahinose. 



Acetochloroarabinose (1'6 gram) was dissolved in warm methyl 

 alcohol (50 CO.), and the mixture was allowed to remain at the tem- 

 perature of the laboratory for four days. Silver carbonate (1"6 gram) 

 was added, and the precipitate filtered. After evaporating the filtrate 

 on the water-bath, the residue was dissolved in a little methyl alcohol, 

 refiltered, and let evaporate spontaneously in a vacuum desiccator 

 over calcium chloride. Leaf-like aggregates of crystals separated. 

 They were free from chlorine, and did not reduce Fehling's solution 

 before hydrolysis. After repeated recrystallizations from hot methyl 

 alcohol, the crystals, when dried at 105°C., became soft at 159° C, and 

 melted at 166-168° C. 



Methyl arabinoside obtained by Fischer's method becomes soft at 

 165° C, and melts at 169-176° C. It crystallizes in needles or leaf- 

 like aggregates, and does not reduce Fehling's solution.^ 



Action of an Alkaline Solution of Canacrol on Acetochloroaralinose. 



Slightly more than equivalent quantities of potash and carvacrol, 

 dissolved in absolute alcohol, were added to a solution of acetochloro- 

 arabinose (7 grams) in absolute alcohol. The mixture was allowed to 

 remain at the temperature of the laboratory for a few days. A white 

 solid separated, and the solution smelt of acetic ester. The filtrate 

 from the potassium chloride was evaporated on the water-bath, and 

 the residue dissolved in water. The aqueous solution was evaporated 

 a few times with addition of water, until the odour of carvacrol had 

 disappeared. 



The residue crystallized on cooling. The reaction had proceeded 

 thus : — 



CH2 OAc CH (CHOAcjsllH + C6H3CH3C3H7 OK + 3C2H5OH 

 I 

 CI 



I ^ 



= CH2OH CH (CH0H)2 CH + KCl + 3CH3 COOC2 Hj 



- C6H3 CH3 C3 H7 



^ Berichte, xxvi., 1893, p. 2400. 



R.I.A. PROC, VOL. XXIV., SEC. B.] 2 / 



