D-Glucoses and Boric Acid

In 1911, when our first investigations of the action of a- and /3-d-glucose on boric acid were made, the furanose structure was assumed for the monosaccharides having four and more carbon atoms, so that the establishment of an equilibrium between a- and /3-D-glucose was represented by the following formulas, written now according to present conventions. 

Change of Rotation and Condiictivity with Time for Solutions of a-v -Glucose and Boric 

Change of Conductivity with Time for Solutions of P-D-Glucose and Boric Acid (Data of Boeseken, Reference 146) 

The negative behavior of sucrose also confirmed our view, for all the eight hydroxyl groups are unfavorably situated and no increase in the conductivity was to be expected. 

The comparatively easy formation of l,2 5,6-diisopropylidene-n-glucofuranose appeared to support this deduction. But the failure 

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