1654 
Chemistry. — “The configuration of a-galactose and a-fructose.” 
By Prof. J. BörseKEN, A. H. Kerstsens and C. B. Kamer. *) 
(Communicated in the meeting of March 25, 1916.) 
In a previous article one of us has used the influence of the 
polyhydroxy-compounds on the conductivity of boric acid to determine 
the configuration of the «- and of the g-glucose. Starting from the 
assumption that a positive influence is caused by the formation of 
“complex acids and that this is promoted by a favourable position 
of the hydroxyl-groups, it could be expected that cane sugar and 
raffinose should exert no positive influence; on the other hand their 
cleavage products might do so. 
In the non-reducing polysaccharides the hydroxyl groups attached 
to adjacent C-atoms which form part of the furane-rings are nowhere 
situated at the same side of those rings; in the reducing cleavage 
products: glucose, fructose and galactose this may, however, be 
the case, namely in one of the mutarotation isomerides of each of 
those three sugars. In the other mutarotation isomeride, the position 
of the hydroxyl-groups is certainly more unfavourable. 
Hence, we could expect: 
dst. that the two mutarotation isomerides should exert a different 
influence on the conductivity of borie acid; 
gnd, that that influence would change in aqueous solution and 
would decrease with the one isomeridé and increase with the other; 
3rd, that this phenomenon should run quite parallel to the muta- 
rotation, i.e. that it would proceed under the same circumstances 
(in. presence of boric acid) unimolecularly and with a same 
reaction-constant. 
With the glucoses these demands have been completely fulfilled 
and as the «-glucose exerted a greater influence on the borie acid 
than the g-glucose, we could take the subjoined symbols as proved.’) 
We have now also carried out this investigation with the «-galac- 
tose and the «-fructose (the g-galactose and the g-fructose have not 
yet been obtained in a sufficiently pure condition). From the symbols 
of the two mutarotation isomerides of the galactose we notice that 
they are constructed quite analogous to the glucose, only the tail 
CHOHCH,OH occupies another position in regard to the furane-ring. 
1) Some of the measurements described here have been executed by Mr. W. Sturm 
2) In the Proceedings of the Meeting of Sat. June 29. 1912 pag. 221 these symbols. 
are given incorrectly. 
