Carbohydrates by reductive amination

Many types of derivatives of cellulose have been used to prepare affinity adsorbents.51 0-(2-Aminoethyl)cellulose and 0-(carboxy-methyl)cellulose can be coupled to carbohydrates bearing carboxyl or primary amino groups by the carbodiimide method.52,53 Cellulose derivatives bearing amino groups can be coupled to reducing carbohydrates by reductive-amination reactions25 in which the Schiff base produced in the initial reaction is reduced with sodium cyanoborohy-dride.54... 

Table 6 Chromophore (UV) and fluorophore (FL) compounds for labeling the reductive carbohydrates by reductive amination...

In some instances, reducing sugars are present that can be reductively aminated without prior periodate treatment. A reducing end of a monosaccharide, a disaccharide, or a polysaccharide chain may be coupled to a diamine by reductive amination to yield an aminoalkyl derivative bound by a secondary amine linkage (Figure 1.96). Also see Section 4.6, this chapter, for an extensive discussion on carbohydrate modification techniques. 

Figure 7.15 The reducing end of a glycan or a carbohydrate can be used to conjugate to an amine-dendrimer by reductive amination, which results in the formation of a secondary amine linkage.

Conjugation of HRP by reductive amination can be done by oxidizing the carbohydrate on the enzyme and subsequently coupling to the amines on (strept)avidin (Figure 23.5). 

Gray, G.R. (1978) Antibodies to carbohydrates Preparation of antigens by coupling carbohydrates to proteins by reductive amination with cyanoborohydride. In Methods in Enzymology, (V. Ginsburg, ed.), Vol. 50, pp. 155-160. Academic Press, New York. 

The native reducing ends of carbohydrates also may be conjugated to amine-containing molecules by reductive amination. The reaction, however, typically is less efficient than using periodate-created aldehydes, since the open structure is in low concentration in aqueous solutions compared to the cyclic hemiacetal form. The... 

Vol. L [12]. Antibodies to Carbohydrates Preparation of Antigens by Coupling Carbohydrates to Proteins by Reductive Amination with Cyanoborohydride. G. R. Gray. 

Applications with sodium cyanoborohydride now include the synthesis of large molecular entities used in biological testing. Conjugation of lactose to human serum albumin by reductive amination (eq 37) and carbohydrate conjugation with PEG amines have been added to the array of transformations reported for NaBHsCN. 

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