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XXI.—On the Compounds of Ethyl-, Propyl-, Butyl-, and Amyl- Thetines. 
By Dr E. A. Letts. 
(Sent for Publication 19th August 1878.) 
Compounds of Ethyl-Thetine.—In the course of the investigations, the results 
of which are recorded in the preceding paper, Professor Crum Brown and I 
observed that sulphide of ethyl, like sulphide of methyl, forms a crystalline 
compound with bromacetic acid.* This we called hydrobromate of diethyl- 
thetine, in conformity with the system of nomenclature we had proposed for 
such bodies— 
CH, C,H, 
| 
Br—S—CH,—COOH. Br—S—CH,—COOH . 
| 
CH, C,H, 
Hydrobromate of Dimethyl-Thetine. Hydrobromate of Diethyl-Thetine. 
Owing, however, to the extremely deliquescent nature of the substance, we 
did not at the time subject it to a closer examination, but devoted our attention 
to the methyl compound and its derivatives. The following are the results of 
an examination which I have since made of the hydrobromate of diethyl-thetine 
and its derivatives :— 
Hydrobromate of Diethyl-Thetine.—50 grms. of sulphide of ethyl and 70 
germs. of bromacetic acidt were shaken together. The acid slowly dissolved, 
occasioning a fall of temperature in so doing from 20-14°. After about half 
an hour’s standing, the mixture grew warm, and deposited a slightly brown, oily 
liquid. The reaction was very much less intense than in the case of the methyl 
compound, when the sulphide of methyl actually boils and the mixture has to 
be cooled to prevent loss of product. 
Next day a greater part of the oily liquid had crystallised, but the formation 
of crystals continued for about three days, and even then a considerable 
quantity of sulphide of ethyl remained unacted on. 
The whole of the solid crystalline matter that had formed was pounded in 
a mortar with ether, and this treatment was repeated twice, to remove excess 
of sulphide of ethyl and bromacetic acid. Most of the product was then dried 
in a desiccator and reserved for the production of other salts, but a consider- 
able quantity was dissolved in hot alcohol, the solution allowed to cool, and 
* “Proceedings,” viii. 220, 385. 
+ Equi-molecular quantities of the two substances require, for 50 of sulphide of ethyl, 77 of 
bromacetic acid ; the sulphide of ethyl was therefore slightly in excess. 
VOL. XXVIII. PART II. 7M 
