JACKSON AND GRINDLEY. — ACETALS FROM QUINONES. 437 



obtained by J. U. Nef* from quiuone would prove that the four 

 ethoxy groups were attached to the carbonyl radicals of the quinone 

 molecule, and thus settle the constitution of this whole class of com- 

 pounds. The chances of the formation of such addition compounds 

 were, however, small, as Nef has shown f that dichlordiethoxyquinone 

 does not take up bromine, a result which we can confirm ; neverthe- 

 less we felt that it would be unwise to neglect this experiment. 

 Accordingly, 0.5 gram of bromine dissolved in chloroform was added 

 to 0.5 gram of the acetal also dissolved in dry chloroform. Even the 

 first drop of the bromine imparted a distinct yellowish red color to 

 the solution, showing that no bromine addition compound had been 

 formed. When all the bromine had been added, the solution was 

 allowed to evaporate spontaneously, and, although the residue was 

 colored slightly, it was found that the weight had not increased, and 

 after one recrystallization from ligroine it gave the melting point of 

 the unaltered acetal 101°-102°. In another experiment the chloro- 

 form solution was evaporated to dryness on the water bath, and the 

 same results were obtained. Under no conditions that we have found 

 could the acetal be induced to take up bromine. The negative out- 

 come of these experiments cannot be used^in deciding the constitution 

 of the acetal, since its inability to take up bromine is more likely to 

 be due to the presence of the two atoms of chlorine and two ethoxy 

 groups attached to the benzol ring than to the occupation of the 

 double bonds by the four additional ethoxy groups, since dichlordie- 

 thoxyquinone does not take up bromine, as has been already stated, 



Dicldordiethoxyquinone Dihenzoyldiethylacetal, 



When the diethylhemiicetal itself or its sodium salt was treated 

 with benzoyl chloride at 100° in a sealed tube, no benzoyl compound 

 was formed, but tlie main products were dichlordiethoxyquinone and 

 ethylbenzoate. A similar result was obtained when the sodium or 

 silver salt of the hemiacetal was suspended in ether, and then treated 

 with benzoyl chloride. When, however, the sodium salt was sus- 

 pended in alcohol instead of ether and benzoyl chloride added, the 

 dibenzoyl derivative was readily formed, and only a trace of dichlordie- 

 thoxyquinone was produced. The following method was found to be 

 the best for the preparation of this substance. To 10 grams of the 

 sodium salt of the dichlordiethoxyquinone diethylhemiacetal suspended 



* Amer. Chem. Journ., XII. 483. t Ibid., XI. 20. 



