Glucose reaction with boric acid

A comparative study of the chelation of 2-deoxy-D-ribose with boric, germanic, telluric, and arsenious acids using potentiometry has shown that only 1 1 complexes are formed. Values of the chelation constants were compared with those of the pentoses. A similar study on mannitol and glucose with boric acid demonstrated that the former was about 740 times more effective a complexant than glucose, but that the conclusions were complicated by the degree of association of boric acid in solution. Reactions at the anomeric centre of mannofuranose have been carried out by means of the 2,3 5,6-ethylboronate (1) formed by treatment of D-mannose with limited triethyl boroxine. By the same means D-lyxose gave the 2,3-blocked lyxofuranose (2) also useful for... 

A study of the stability of compounds derived from D-glucose and D-fructose with boric acid or phenylboronic acid has found that the stability constants for the fructose compounds are much greater than those for the glucose compounds. The synthesis of crystalline 3-0-acetyl-2,4-0-phenylboranediyl- -D-ribopyranosyl bromide in a two pot process from D-ribose has been described along with some of its selective glycosylation reactions. Ethyl (dimethoxy)borane has been used in the synthesis of anomerically pure furanosides from the free sugars. Thus methyl 2,3-0-ethylboranediyl-tt-D-lyxofuranoside was prepared and then de-esterified under essentially neutral conditions to the glycoside in 80%... 

Borate complexes have been utilized by Brigl and Griiner47 to effect partial esterification. Anhydrous D-glucose and metaboric acid dissolved in acetone give a complex which exhibits the analysis of a diborate. Reaction of the latter with an excess of benzoyl chloride gives 2,6-di-O-benzoyl-D-glucose (XL). D-Mannitol likewise forms a diborate, which produces the 1,6-di-O-benzoyl derivative (XLI) upon benzoylation. In the presence of boric acid, D-glucose diethyl thioacetal yields the 6-benzoate (XLII). In the non-aqueous medium the formation of complexes... 

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