(GOL) 
On the Action of Oxidising Agents on Compounds of Dimethyl-Thetine. 
By Dr E. A. Lerts. 
(Sent for Publication August 19, 1878.) 
In a former paper by Professor Crum Brown and myself,* some preliminary 
experiments were described on the products of the oxidation of dimethyl-thetine 
and its salts. We stated that when nitrate of dimethyl-thetine is acted on by 
nitric acid, two distinct products of oxidation are formed,—the one a neutral 
substance, readily crystallising from alcohol in long colourless needles, the other 
apparently an uncrystallisable body possessing acid properties, and readily form- 
ing a crystalline barium salt. We found that the base dimethyl-thetine is readily 
acted on by permanganate of potash in acid or alkaline solution, and that 
apparently only the crystallisable product of oxidation results. 
We also found that fuming nitric acid acts readily on solid hydrobromate of 
-dimethyl-thetine ; bromine is separated, and on driving off the excess of nitric 
acid a syrup remains which fumes like hot sulphuric acid. This syrup also 
possesses acid properties and forms a well-marked barium salt. 
The last oxidising agent with which we experimented was chromic acid. 
That substance, strange to say, exercises no oxidising action at all on the base 
 dimethyl-thetine, but simply combines with it to form a chromate, which on 
drying solidifies to a yellow gummy mass, and cannot be obtained in crystals. 
The same compound was obtained by the action of chromate of silver on the 
| hydrobromate of dimethyl-thetine. 
These results appeared sufficiently interesting to warrant a somewhat closer 
study of the action of oxidising agents on dimethyl-thetine and its compounds, 
and accordingly I undertook the investigation, the results of which follow. 
| Action of Nitric Acid on Nitrate of Dimethyl-Thetine.—A solution of the 
_ nitrate was prepared by acting on a solution of the hydrobromate of dimethyl- 
thetine with nitrate of silver, filtermg from the precipitated bromide of silver, 
and removing the slight excess of nitrate of silver by careful addition of 
hydrochloric acid. The solution of the nitrate thus prepared was mixed with 
an equal volume of the ordinary strong nitricacid of the laboratory. The 
mixture was then heated in a water-bath, when copious red fumes were 
disengaged. When these ceased to be evolved the greater part of the nitric 
acid was distilled off, and the remaining liquid heated on a water-bath until it 
| ceased to give the nitric acid reaction. On then allowing it to cool, it solidified 

* “Proceedings,” vol, viii. p. 508. 
