402 PROCEEDINGS OF THE AMERICAN ACADEMY. 



have been unable to arrive at a definite conclusion on this subject, 

 and it is hoped that it will be possible to repeat the experiments on 

 a larger scale and with conclusive results early in the coming term. 

 A bromdinitrophenylbrommalonic ester corresponding to the picryl 

 compound mentioned above was also prepared. It melts at 72°-73°. 



Trinitrophenyhnalonic Ester {Picryhnalonic Ester), 

 C6H2(N02)3CH(COOC2H5)o. 



As Dittrich* states that the product of the reaction of picrylchloride 

 and sodium malonic ester is viscous, we first turned our attention to 

 the preparation of the sodium salt of the substituted malonic ester in 

 the hope that this might be purified more easily than the free ester. 



Sodium Plcrylmalonic Ester, C6H.j(NOo)3CNa(COOC2H5)2. 



The picrylchloride used in making this substance was prepared 

 according to the method of Clemm,t except that we crystallized the 

 chloride from a mixture of chloroform and alcohol, as we found that 

 the addition of the chloroform made it possible to work with much 

 smaller volumes of the solvent, and also seemed to prevent in great 

 measure the deposition of the picrylchloride in an oily form. A strong 

 cold benzol solution of 10 grams of this picrylchloride was mixed with 

 an alcoholic solution of sodium malonic ester made from 14 grams of 

 malonic ester and the sodic ethylate from 2.1 grams of metallic sodium. 

 The mixture, which took on at once a deep red color, was cooled at 

 first, and then allowed to stand for twelve hours at ordinary tempera- 

 tures ; after which it was diluted with about three quarters of a litre 

 of water. In this way a red aqueous solution was obtained, and a 

 supernatant layer of benzol which contained a portion of the picryl- 

 malonic ester formed, while the rest was dissolved as a sodium salt 

 in the red aqueous solution, in addition to some sodic picrate and the 

 sodic chloride. Upon acidifying the aqueous liquid with sulphuric 

 acid a yellow precipitate was thrown down, which as it settled from 

 the liquid collected in an oily state on the bottom of the beaker. To 

 the oily product a strong solution of sodic hydrate was added, which 

 imparted to it a dark red color, and after thorough mixing converted 

 it into a red crystalline solid. To remove any liquid or viscous 

 impurities from the salt, it was next dissolved in the smallest possible 

 amount of alcohol and treated with an excess of benzol, after which 



* Bar. d. ch. G., XXIII. 2720. 1 Journ. Prakt. Chem., [2.], I. 145. 



