Esters carbohydrate, reaction with ammonia

Cellobiose was prepared first by Skraup and Konig by the saponification of the octaacetate with alcoholic potassium hydroxide, and the method was improved by Pringsheim and Merkatz.3 Aqueous barium hydroxide also has been employed for the purpose, and methyl alcoholic ammonia has been used extensively for the hydrolysis of carbohydrate acetates. The method of catalytic hydrolysis with a small quantity of sodium methylate was introduced by Zemplen,i who considered the action to be due to the addition of the reagent to the ester-carbonyl groups of the sugar acetate and the decomposition of the addition compound by reaction with alcohol. The present procedure, reported by Zemplen, Gerecs, and Hadacsy, is a considerable improvement over the original method (see Note 2). 

THE REACTION OF AMMONIA WITH ACYL ESTERS OF CARBOHYDRATE S ... 

The first study1 on the reaction of a carbohydrate ester with ammonia was performed in 1893 by Wohl, who submitted 2,3,4,5,6-... 

REACTION OF AMMONIA WITH CARBOHYDRATE ACYL ESTERS 83... 

Gelpi, Maria E., and Cadenas, Raul A., The Reaction of Ammonia with Acyl Esters of Carbohydrates, 31, 81-134... 

For the methylation of the free hydroxyl groups of a partially esterified carbohydrate, e.g., of a partially acetylated compound, only the Purdie method is available. Although liquid ammonia does not react with esters at — 70°C., there is a danger of saponification if the temperature of the reaction mixture is allowed to rise before all the ammonia has been removed. The aqueous alkali employed in the methods of Haworth or Menzies will, of course, remove ester groups by hydrolysis. 

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