VOL. 12 (1953) BIOCHIMICA ET BIOPHYSICA ACTA 203 



DEGRADATION OF ALDOSES BY MEANS OF THEIR DISULFONES 



by 



D. L. MacDONALD and HERMANN O. L. FISCHER 



Department of Biochemistry, University of California, Berkeley (U.S.A.) 



The most elegant method to shorten the carbon chain of a sugar with regard to 

 mildness of conditions and good yields is no doubt the splitting of the chain by lead 

 tetra-acetate or periodic acid. Since both reagents however require as point of attack a 

 pair of free hydroxy Is on adjacent carbon atoms with the rest of the hydroxyls blocked 

 by an easily removable substituent, it is not always easy to obtain a suitable starting 

 material. 



Good examples for this procedure are a series of reactions^ leading from D-glucose, 

 via D-sorbitol and 1,3-2,4-diethylidene D-sorbitol to diethylidene L-xylose which upon 

 hydrolysis yields L-xylose, or the preparation of the same pentose^ by oxidation of 2,4- 

 benzylidene D-sorbitol with lead tetra-acetate and subsequent hydrolysis. 



More generally applicable for the degradation of an aldose to the next lower sugar 

 are the classical methods by Weermann, Ruff and Wohl. 



Weermann^ degrades the amide of the easily prepared aldonic acid e.g. D-gluconic 

 acid amide by means of sodium hypochlorite to D-arabinose. Since NaOCl also oxidizes 

 the newly formed arabinose the yield leaves much to be desired. 



A similar disadvantage is inherent in the well-known method of Ruff*. Here the 

 aldonic acid is oxidized with hydrogen peroxide in the presence of ferric acetate. This 

 method more recently has received much study and, in 1950, Fletcher, Diehl and 

 Hudson^ reported considerable improvements in the preparation of D-arabinose from 

 calcium D-gluconate and D-lyxose from calcium D-galactonate. Ion-exchange resins, 

 not available at the time of earlier work, were successfully used to remove gross quantities 

 of organic and inorganic materials, thus greatly enhancing the yield of the pentose. 



The well-known Wohl degradation® uses as starting material the sugar oximes and 

 involves the removal of the cyanide group from the acetylated nitrile which can be for- 

 med from the oxime by acetylation with acetic anhydride and sodium acetate. Many 

 papers are concerned with determining optimal conditions'' for the degradation of the 

 acetylated nitriles, but a later paper by Wohl and Wollenberg^ has found little atten- 

 tion. These authors demonstrate that the degradation of free gluconic acid nitrile by 

 water at 100° yields pure crystalhne D-arabinose in a yield of 84 per cent. 



An interesting new method of sugar degradation, starting like the Wohl method 

 from the oxime of aldoses, has recently been published by Weygand and Lowenfeld^. 

 These authors react the oxime of an aldo sugar with 2,4-dinitrofluorobenzene, and the 

 next lower aldose is formed along with 2,4-dinitrophenol and HCN. 



Recently, a novel method of sugar degradation has been described^^ which utilizes 

 the sugar mercaptals as the starting point for the conversion of a hexose into the corres- 

 References p. 206. 

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