ALCOHOL ON HYDROBROMATE OF DIMETHYL-THETINE. 609 
action of alcohol on the dibromacetic acid contained in the crude bromacetic 
acid employed, which, as a rule, was not specially purified, but boiled between 
200° to 215° C., the pure acid boiling at 208° C. In order to ascertain 
whether the oily liquids owed their production to the presence of these acids, 
the following experiments were made :— 
143 erms. of bromacetic acid (boiling point 200°-215°) were treated in 
the usual way, for the preparation of hydrobromate of dimethyl-thetine, with 
80 germs. of sulphide of methyl (about 16 grms. in excess of the theoretical 
quantity). Next morning, when the action was complete, the crude thetine 
compound was purified by washing it repeatedly with ether in which bromacetic 
and dibromacetic acids readily dissolve. The residue, after this washing, con- 
sisted of a pure white powder, from which the last quantities of ether were 
removed by heating it in a water-bath. It was then boiled for about 10 minutés 
with 150 c.c. of absolute alcohol. The resulting solution had a very feebly 
irritating odour, and was not precipitated by water, even on the addition of 
common salt. It was then left a night, and yielded magnificent colourless 
crystals of the thetine compound. The residual solution was poured off from 
these and heated in a flask, to which was fitted a vertical condenser, the inner 
tube of which was connected by means of a glass tube with a vessel contain- 
ing alcohol to absorb volatile products, especially sulphide of methyl. The 
alcoholic solution of the thetine was boiled for several days. From time to 
time it was tested with water to see whether oily drops precipitated, and this 
was found to occur after some time, the quantity increasing day by day. When 
the quantity of oily liquid thus precipitated appeared to cease increasing, the 
mixture was distilled from a water bath. The residue was then mixed with 
| water, and the liquid which separated washed several times with water. It 
weighed about 44 germs. The aqueous washings and the water employed to 
precipitate the oily liquid were evaporated over a water-bath, and left a residue 
_ which solidified to a crystalline mass. 
| The aqueous solution of this gave— 
With acetate of lead in the cold, a white amorphous precipitate, which 
dissolved on warming it with the solution, and was almost immediately 
replaced by a white crystalline salt. 
When neutralised with ammonia, and mixed with a concentrated solution 
of sulphate of copper—a greenish-white crystalline precipitate. 
When neutralised with solution of caustic baryta, and warmed—white 
| crusts. 
When neutralised with hot concentrated baryta solution, and the mixture 
‘allowed to cool—tufts of colourless blunt needles. 
These reactions are characteristic of thiodiglycollic acid. The production 
lof thiodiglycollic acid is simply due to the decomposition of the hydrobromate 
