250 PROCEEDINGS OF THE AMERICAN ACADEMY 



XX. 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 

 HARVARD COLLEGE. 



ON SOME NITRO DERIVATIVES OF 

 METABROMTOLUOL, 



By W. B. Bentley and W. H. Warren. 



Presented May 28, 1889. 



Determination of the Constitution of Metabromdinitrotoluol, 

 C 6 II 2 CH 3 Br(N0 2 ) 2 . 



Our attention was first called to this subject by Prof. C. Loring 

 Jackson, who, having with W. S. Robinson* obtained the metabrom- 

 dinitro toluol by the decomposition of their bromdinitrophenylmalonic 

 ester, asked us to determine its constitution. 



This metabromdinitrotoluol, melting point 103°-104°, was discovered 

 by Grete,f who made it by the action of fuming nitric acid on meta- 

 bromtoluol, or metabrommononitro toluol, and assigned to it the con- 

 stitution CH 3 , N0 2 , Br, N0 2 , 1, 2, 3, 4, although he was very doubtful 

 about the position of the second nitro group, giving it the para posi- 

 tion without any experimental reason for doing so. His proof that 

 one of the nitro groups was in the ortho position consisted in estab- 

 lishing the identity of the bromtoluidine made by the reduction of his 

 bromnitrotoluol with that obtained by the action of bromine on ortho- 

 acettoluid ; % but this obviously leaves it doubtful whether this nitro 

 group stands in the position 2 or 6 to the methyl of the toluol, and in 

 fact later work has shown that Grete was wrong in ascribing to it 

 the position 2, as his mononitro compound really has the constitution 

 CH 3 , Br, N0 2 , 1, 3, 6. The proof of this was given by Nevile and 

 Winther,§ who, by replacing the amido group in the metabromor- 

 thotoluidine (melting point 55°-56°) already mentioned by bromine, 



* See preceding paper. 



t Ann. Chem., clxxvii. 258. 



X YVroblewsky, Ann. Chem., clxviii. 1G1. 



§ Ber. d. eh. G., xiii. 962. 



