Ss ae 
. 
TRANSACTIONS OF SECTION B. 443 
case of fructose diacetone ? was converted into monomethyl glucose diacetone (b.p. 
139° to 140°/12 mm., [a]i’°—32°-2 in alcoholic solution). When heated in aqueous 
alcohol containing 0:4 per cent. of hydrogen chloride the two acetone residues were 
removed simultaneously, and, on working up the product in the usual way, monomethyl 
glucose was obtained in good yield. Both the a-and 8-forms of the sugar were isolated, 
the former being deposited spontaneously from methyl alcoholic solutions, while 
the latter was precipitated from concentrated solutions in methyl aleohol by the 
addition of acetone. 
aform: Rectangular plates; m.p. 157° to 158°. Mutarotation in aqueous 
solution :— 
[a]b + 96°-7 > 55°-5. 
B-form: Acicular prisms; m.p. 130° to 132°. Mutarotation in aqueous 
solution :— 
[ajp +31°-9 ——— 55°-1. 
The sugar was shown to possess the structure 
CH,OCH, - CHOH - CH -CHOH - CHOH - CHOH 
| 
O | 
from the fact that it gave the same monomethyl glucosazone as that obtained from 
monomethyl fructose.* 
Monomethyl methylglucoside, prepared by Fischer’s method, failed to crystallise, 
the specific rotation of the mixed a- and 8-forms in alcoholic solution being +99°:3. 
Dimethyl Glucose. 
Methylation of benzylidene a-methylglucoside gave an excellent yield of benzylidene 
dimethyl a-methylglucoside (m.p. 122° to 123°; [a]h +97°-0 in acetone solution). By 
carefully regulated hydrolysis a molecule of benzaldehyde was eliminated and dimethyl 
a-methylglucoside was formed (m.p. 80° to 82°; [a]i,) +-142°-6 in aqueous solution). 
On complete hydrolysis the glucoside was converted into dimethyl glucose, which was 
isolated in a- and B- forms. The 8-modification melted at 108° to 110° and separated 
in delicate needles from dilute solutions of the sugar in ethyl acetate, while the a- 
variety (m.p. 85° to 87°) was obtained by the addition of dry ether to a concentrated 
solution in ethyl alcohol. The mutarotation of each was determined in pure acetone. 
B-form : [a]p’"+5°-9 —— > +50°-9 a-form: [a]f’+81°-9 —__-> +.48°.3. 
The sugar, under conditions favourable to csazone formation, gave a dimethyl- 
glucosephenylhydrazone and has thus the probable structure :— 
CH,OH : CHOH - CH - CHOCH, - CHOCH, - CHOH 
| | 
| —_-0 
Trimethyl Glucose. 
Glucose monoacetone was converted into trimethyl glucose monoacctone (b.p. 138° 
to 139°/12 mm.), from which, on hydrolysis, trimeth,/ glucose was obtained. The 
sugar failed to crystallise, and thus the specific rotation could only be determined for 
the equilibrium mixture of a- and f-forms ([ajj’—8°-3 for both alcoholic and 
aqueous solutions). No solid glucoside, hydrazone, or other derivative could be 
obtained. The constitution, deduced from that of glucose monoacetone, is expressed 
by the formula :— 
CH,OCH, - CHOCH, - CH - CHOCH, - CHOH - CHOH 
O 
Discussion of the Optical Results. 
Ten out of the possible thirty-one methylated glucoses are now available for 
comparison. We find that the rotatory powers of these substituted glucoses are on'y 
slightly affected by changes in concentration or by change of solvent. Further, in 
the case of mutarotatory forms, accurate initial values can be determined in acetone 
solution, as the optical change remains suspended until a catalyst is added. We are 
2 Chem. Soc. Trans. 1909, 95, 1223. a Boer cit. 
