Mannonic acid formation

The rates of hydrolysis of the lactones depend on the parent structure for instance, the 1,4-lactone of D-mannonic acid is more stable than that of D-gluconic acid, and the 1,4-lactones of 2-deoxyaldonic acids are more stable than the corresponding aldonolactones. The final attainment of equilibrium between free aldonic acids and their lactones is reached only after many days at room temperature it is, however, accelerated by the presence of strong acids and by heating. A detailed discussion of the formation and hydrolysis of aldonolactones is available in a review by Shafizadeh,59 and the conformations and stabilities of aldonolactones have been discussed by Lemieux.60 Detailed analyses of D-glucono-1,5-lactone and other lactones have been reported.61 13C NMR spectroscopy proved to be a convenient method for monitoring the equilibria.62... 

Fig. 8-18. Oxidative stabilization of cellulose through formation of aldonic acid end groups. R is cellulose chain. After oxidative formation of a glucosone intermediate this undergoes a benzilic acid rearrangement strongly favoring formation of mannonic acid end groups (2). In addition, cleavage of C-1 to C-2 and C-2 to C-3 bonds gives rise to the formation of arabinonic acid (3) and erythronic acid (4) end groups. (In this simplified scheme only the main products are shown.)...

L-Glucose can be synthesized from L-arabinose by the Fischer-Kiliani synthesis, but the synthesis is long and tedious [42] due in part to the difficulty in separating L-gluconic acid from the preponderant L-mannonic acid. In contrast, the synthesis of L-glucose by the addition of nitromethane to L-arabinose results in the formation of two epimeric 1-nitroalcohols that are readily separated by fractional crystallization [43]. This results in the synthesis of L-glucose (reaction... 

Certain Acetobacter strains also form dike-tonic acid. Similarly, other aldoses, mannose and galactose, lead to the formation of mannonic and galactonic acid. 

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