Of aldonic acids

Derivatives of aldoses in which the terminal aldehyde function is oxidized to a car boxylic acid are called aldonic acids Aldonic acids are named by replacing the ose ending of the aldose by omc acid Oxidation of aldoses with bromine is the most com monly used method for the preparation of aldonic acids and involves the furanose or pyranose form of the carbohydrate... 

Although the Tollens reaction is a useful test for reducing sugars, it doesn t give good yields of aldonic acid products because the alkaline conditions cause decomposition of the carbohydrate. For preparative purposes, a buffered solution of aqueous Br2 is a better oxidant. The reaction is specific for aldoses ketoses are not oxidized by aqueous Br2. 

Oxidation of Aldonic Acids. Preferential oxidation of the secondary alcoholic group adjacent to the carboxyl group in sugar acids or aldonic acids such as L-gulonic acid (XXV) can be carried out with chromic acid12 or with chlorates in the presence of a vanadium catalyst.13... 

G. Hourdin, The catalysis of the Ruff oxidative degradation of aldonic acids by titanium-containing zeolites, Catal. Lett., 69 (2000) 241-244. 

Deulofeu, Venancio, The Acylated Nitriles of Aldonic Acids and Their Degradation, IV, 119-151... 

The hydroxyl groups of aldonolactones react with a variety of aldehydes and ketones to give the corresponding acetal derivatives. Treatment of the salts of aldonic acids with benzaldehyde and hydrochloric acid or zinc chloride as catalysts give benzylidene derivatives of aldonic acids or aldonolactones (3). 

Glucose Oxidase-catalysed Synthesis of Aldonic Acids 323... 

The aldose (11.1 mmol) was dissolved in water to a final concentration of 0.5 m and subjected to oxidation by addition of glucose oxidase (200 mg, 400 U) and a large excess of catalase (1 mL, 25 kU). The mixture was vigorously stirred under air and the pH was kept constant at 7.5 by means of a pH-stat adding continuously 1 m NaOH. The conversion degree was directly calculated considering the volume of added 1 m NaOH, since 1 mol of NaOH neutralizes 1 mol of aldonic acid formed. 

Reductions with sodium amalgam are fairly mild. Only easily reducible groups and conjugated double bonds are affected. With the availability of sodium borohydride the use of sodium amalgam is dwindling even in the field of saccharides, where sodium amalgam has been widely used for reduction of aldonic acids to aldoses. 

K. Bock, I. Lundt, and C. Pedersen, Reaction of aldonic acids with hydrogen bromide. I. Preparation of some bromodeoxyaldonic acids, Carbohydr. Res., 68 (1979) 313-319. 

Afterward, Behrend found that the nitrile is also produced when o-glucose oxime is treated with pyridine and acetic anhydride, and this method has been extended to the preparation of other nitriles of aldonic acids. ... 

Apart from the general procedures that have been described, nitriles of aldonic acids are capable of other reactions that also lead to degradations. 

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