Glucose condensation with aromatic amines

Sugars such as glucose and mannose have been analyzed by condensing the oxygen of the anomeric carbon atom with aromatic amines to form water. Koshland and Stein (1954) heated glucose with an excess of p-phenylene diamine for 15 minutes at 150°C., and Halpern and Leibowitz (1959) heated mannose with wi-phenylene diamine at 97°C. The water formed is distilled off and equilibrated with COj in the usual manner. Small corrections are required owing to the occurence of side reactions with other oxygen atoms. 

Schiff, for example, had included carbohydrates in his studies on the formation of Schiff bases from aldehydes and amino compounds. He heated D-glucose with aniline or withp-toluidine in substantia [11], and described that these components, under loss of water, formed yellow glass-like condensation products. These supported his suggestions on the formation of Schiff bases from aldehydes and suitable aromatic amines [12]. 

Condensation reactions. These are based on the reaction of glucose in hot acetic acid with various aromatic amines, e.g. aniline or o-toluidine to produce coloured derivatives. Other sugars can also react, giving falsely high values. 

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