Polysaccharides Smith degradation

Only a few methods for the specific degradation of polysaccharides were known when an earlier article on structural polysaccharide chemistry appeared in this Series.3 The Smith degradation,4 which has become the most frequently used, had only just been introduced. Since then, a number of specific degradation techniques have been developed. In addition, there have also been some modifications and improvements to existing methods. In this article, chemical methods for specific or selective degradation of polysaccharides, and their applications in structural analysis, will be discussed. Enzymic methods, which may be of considerable value, have already been treated in this Series.5... 

Often, a polysaccharide gives a polymeric residue after a Smith degradation. Methylation analyses of this material and of the original polysaccharide may nonetheless furnish valuable structural information. It is also possible to subject the material to successive Smith degradations, a notable example being the stepwise degradation of the ovarian-cyst, blood-group H substance (42) by Lloyd and Kabat.100... 

Further examples of modified Smith degradation, in which the polyalcohol is methylated prior to hydrolysis under mild conditions, uronic acid degradation, and /3-elimination preceded by oxidation have been reported in connection with structural studies on the Klebsiella type 28 (Ref. 182), 57 (Ref. 183), 59 (Ref. 142), and 81 (Ref. 184) capsular polysaccharides. 

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