OF ARTS AND SCIENCES. 67 



VII. 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 



HARVARD COLLEGE. 



ON THE PRODUCTS OBTAINED BY THE ACTION OF 



NITRIC ACID UPON BROMTRINITROPllE- 



NYLMALONIC ESTER. 



By C. LoRiNG Jackson and W. B. Bentley. 



Presented May 13, 1891. 



Our attention was first called to this subject by the appearance of 

 a vivid red color, when common strong nitric acid was used to set free 

 bromtrinitrophenylmalonic ester from its sodium salt, whereas no such 

 color was observed if hydrochloric or sulphuric acid was used in place of 

 nitric. Upon studying this action, we soon found that a new compound 

 was formed, which could also be obtained from the free bromtrinitrophe- 

 nylmalonic ester by treating it with hot nitric acid for a few minutes,* 

 or for some hours in the cold ; the free ester therefore acts with nitric 

 acid less readily than its salt, for with that the color appeared immediately. 

 The further study of this compound (which was obtained in colorless 

 prisms) proved that its formula was C6HBr(N02)3CN02(COOC2Hj2 ; 

 that is, that it had been formed from the bromtrinitrophenylmalo- 

 nic ester by replacing one of its atoms of hydrogen by the group 

 N02. We have also obtained the following similar derivatives : from 

 the bromdinitrophenylmalonic ester C6H2Br(N02)2CN02(COOC2H5)2, 

 melting point 111°, and from the trinitrophenylenedimalonic ester 

 CeH(N02)3CN02(COOC2H,)2CH(COOC2H5)2, also melting at 111°, 

 so that the reaction seems to be a general one. The position of the 

 group NO2 introduced by the action of nitric acid was determined by 

 the stuly of the acidity of these compounds. In the bromtrinitrophe- 

 nylmalonic ester C6HBr(N02)3CH(COOC2H5)2 there are only two 

 atoms of hydrogen, one on the benzol ring, the other on the side- 

 chain ; if the first of these were replaced by NO2, the effect, if any 



* A preliminary account of this substance forms part of a paper by G. D. 

 Moore, and one of us (these Proceedings, XXIV. 265). The statements made 

 there are superseded by this paper. 



