Formation of Glycosidic Linkages between Monosaccharide Residues

The anhydrides have been used to synthesize higher saccharides. Several disaccharides have been synthesized by reacting Brigl s anhydride with 2,3,4,6-tetra-0-acetyl-P-D-glucopyranose in benzene at 90°C for 37 hr to give a,P-trehalose heptaacetate [80,81] (reaction 4.67). 

P-Maltose heptaacetate was synthesized using Brigl s anhydride with 1,2,3,6-tetra-O-acetyl-P-D-glucopyranoside at 90°C in benzene for 20 hr [82] (reaction 4.68). 

Sucrose was first chemically synthesized using Brigl s anhydride and 1,3,4,6-tetra-O-acetyl-P-D-fructofuranose (the latter prepared by reacting inulin triacetate with HBr in glacial acetic acid [83] (reaction 4.69). 

6 -Thiopanose, a trisaccharide, has been synthesized in a similar manner by reacting 6 -deoxy-6 -iodomaltose heptaacetate with the 1-a-thio-D-glucopyrano-side [86] (reaction 4.74). 

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Because carbohydrates are so frequently used as substrates in kinetic studies of enzymes and metabolic pathways, we refer the reader to the following topics in Ro-byt s excellent account of chemical reactions used to modify carbohydrates formation of carbohydrate esters, pp. 77-81 sulfonic acid esters, pp. 81-83 ethers [methyl, p. 83 trityl, pp. 83-84 benzyl, pp. 84-85 trialkyl silyl, p. 85] acetals and ketals, pp. 85-92 modifications at C-1 [reduction of aldehydes and ketones, pp. 92-93 reduction of thioacetals, p. 93 oxidation, pp. 93-94 chain elongation, pp. 94-98 chain length reduction, pp. 98-99 substitution at the reducing carbon atom, pp. 99-103 formation of gycosides, pp. 103-105 formation of glycosidic linkages between monosaccharide residues, 105-108] modifications at C-2, pp. 108-113 modifications at C-3, pp. 113-120 modifications at C-4, pp. 121-124 modifications at C-5, pp. 125-128 modifications at C-6 in hexopy-ranoses, pp. 128-134. 

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