TRANSACTIONS OF SECTION B. 441 
Where R is a group of low molecular weight. As examples of this class 
we have a-aminomethylglucoside, a-aminoethylglucoside, and a-aminoamyl- 
glucoside. 
A second type of a-aminoglucoside is formed when the group coupled with 
the glucosamine residue contains a benzene ring, as hydrolysis then proceeds 
normally with dilute mineral acids or with enzymes. Representative members of 
this class, to which the usual glucosidic formule may be applied, are a-amino- 
helicin and a-aminosalicin. 
No general account of the preparation of o-aminoglucosides can be given, as 
the method has to be varied to suit individual cases. When the hydroxy- 
compound is readily volatile, a large excess may be employed, and the reaction 
is carried out in the presence of morphine, which removes the hydrogen bromide 
formed in the change. On adding the finely powdered bromotriacetylglucosa- 
mine hydrobromide, a considerable rise of temperature takes place, and the 
condensation is complete in a few minutes. The isolation of the acetylated 
aminoglucoside is then conducted as already described by us.” 
In the case of high-boiling hydroxy-compounds the reaction may be carried 
out as described above, and the crude product precipitated by the addition of 
ether, or, when the solubilities permit, the condensation is conducted in dry 
ether containing pyridine, the solution being shaken with the solid bromo- 
compound for several hours. In such cases the product separates in the course 
of the reaction. ‘These and other variations of the method were necessary when 
solid hydroxy-compounds were employed. The removal of the acetyl groups was 
effected by heating with methyl alcohol containing 1 per cent. of hydrogen 
chloride. In the course of the research, nine aminoglucosides have been exam- 
ined. The list includes morphine aminoglucoside which is an alkaloidal derivative 
of a new type. 
2. The Constitution of Mannitol Triacetone. 
By Professor J. C. Irvine and Miss Bina Mary Paterson, B.Sc. 
The condensation of sugars or po)yhydric alcohols with acetone involves the loss of 
the elements of water from the ketonic group and two hydroxyl groups, and is in 
fluenced in a marked fashion by the configuration of the hydroxy-compound. Tischer, 
on the basis of experiments carried out with glycerol, ethylene glycol, and trimethylene 
glycol, came to the conclusion that the reaction involved hydroxyl groups attached 
to B-carbon atoms, but, for several reasons, this view cannot be applied generally. In 
the case of reducing sugars especially, the reaction is complicated by several factors, 
including the fact that part of the molecule is a ring structure and thus presents the 
possibility of cis and trans condensation with the ketone. The simplest conditions 
for a study of the reaction are thus available in the case of an active polyhydric alcohol, 
and we have, in the meantime, confined our attention to mannitol. 
Although it is impossible to arrest the condensation of mannitol with acetone at 
intermediate stages, we find that by carefully regulated hydrolysis three molecules 
of the ketone can be removed successively from mannitol triacetone. The reaction 
thus gives an index of the varying stability of the ketonic residues and proceeds 
according to the scheme :— 
Mannitol triacetone ——> Mannitol diacetone ——> Mannitol 
monoacetone ——> Mannitol. 
In view of the extreme instability of the intermediate compounds, indirect methods 
had to be employed to determine their constitution. This was effected in each case 
by methylation and subsequent hydrolysis. The resulting compounds were thus 
alkylated in the positions from which the acetone residues had been removed, and the 
position of the methyl groups was finally determined by standard methods. The 
results are summarised below :— 
Mannitol diacetone was prepared by heating a solution of mannitol triacetone 
in 68 per cent. alcohol containing 0-1 per cent. of hydrogen chloride. The hydrolysis 
was continued at 40° for 150 minutes. The compound melted at 37° to 39° and 
showed [a]p +-15°-7 in alcoholic solution (c=2-7). When methylated by the 
silver-oxide reaction it was converted into dimethyl mannitol diacetone, a colourless 
mobile liquid boiling at 140° to 141°/13 mm. and showing [a]p + 21°-9 in alcohol. 
* Toc. cit. 
