414 PROCEEDINGS OP THE AMERICAN ACADEMY. 



result of this experiment was negative, as no bromine was taken up, 

 but this cannot be accepted as an argument against Formula II., since 

 Nef * found that dichlordiethoxyquiuone itself gives no addition com- 

 pound with bromine, — a result which we can confirm. The failure 

 of the tetraethylacetal to form addition compounds must be ascribed, 

 therefore, to the presence of the two atoms of chlorine and two ethoxy 

 groups attached to the quinone ring, rather than to the absence of 

 double bonds. 



It is perhaps worth noting that the formation of these hemiacetalg 

 is easily explained by the diketo formula of quinone, but cannot be 

 brought into harmony with the peroxide formula, so far as we can 

 find. Our work, therefore, would have been of value in determining 

 the constitution of quinone, if it had been done before this question 

 was finally settled by Nef's proof of the diketo constitution through 

 his work on the action of bromine on argentic chloranilate.j 



Since, as we have just proved, our new substance has the two mole- 

 cules of methyl alcohol attached to the two carbonyl groups of the 

 dichlordimethoxyquinone, it belongs to the class of acetals, and we 

 propose to call it and similarly constituted bodies hemiacetals, because 

 only half of the hydrogen in the hypothetical mother group of the 

 acetals =C=(0H)2 has been replaced by the organic radical. Such 

 hemiacetals are not especially uncommon, the most familiar examples 

 being the alcoholates of ordinary chloral and of butylchloral. Jacob- 

 sen, | and later Renard,§ claimed tliat tliey obtained the corresponding 

 compound of acetaldehyd CH3CH(OH)(OC^H5), but do not agree in 

 regard to its boiling point, and apparently assign to it a much greater 

 stability than would be expected in such a substance. Without mul- 

 tiplying examples, we pass at once to some compounds more nearly 

 related to ours, recently obtained by Zincke with some of his scliolars. 

 Zincke and Arnst || by the action (if alcohol on tetrachlordiketohydro- 

 uaphthalin have obtained a compound, 



OH 



co-c( 



cji.: I 



CClo-CClo 



6"4 \^ 



which is tolerably stal)le in the cold, but decomposed by heat, like our 

 hemiacetal. The corresponding para compound formed no such deriv- 



* Am. Chem. .Tourn., XI 20, 24. § Rer. d. ch. G., VIII. 132. 



t Il)i(l.. XII 4RC, II Ann. Cliem., CCLXVII. 319. 



.t BtT. d. ch. G.,IV. 2ir> 



