268 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



represented by the formulas given below, in which it is supposed that an 

 isonitro * compound is formed with the development of a quinoid structure 

 in the benzol ring. The difference between the two formulas is that in 

 II. the quiuoid structure is developed in the para position, in III. in the 

 ortho position. 



II. III. 



0=N-0-Na 



0=N-0-Na 



We have used the formula of the addition product from sodic methylate 

 and trinitranisol, as it is the simplest that will serve in the argument 

 which follows. In applying these formulas to the malonic ester com- 

 pounds it must be assumed that the malonic ester radical which is added 

 to the benzol ring has the constitution -OC(OC2H5)=CIiCOOC2H5, as, 

 if it is assumed to be -CH(COOC.,H5)2, we should have an attachment of 

 carbon to carbon incompatible with the instability of these compounds. 



In applying Formulas I., II., and III. to the explanation of the observed 

 properties of these compounds, we consider first the strong color, their 

 most marked characteristic ; this is explained by the quinoid structure in 

 Formulas II. or III., but is not accounted for by Formula I., since, accord- 

 ing to Hantzsch and Riuckenberger,t their substance 



CH.3 



\ / 



CH-NO 



OC2H5 



NO, 



/ 



\ 



OK, 



which contains the group characteristic of Formula I., has only a pale 

 yellow color. 



The easy decomposition of the colored body by hydrochloric acid with 

 regeneration of the trinitranisol, from which it was formed, is accounted 

 for by either of the three formulas I., II., or III., but the preference should 

 be given to II. or III., since Hantzsch and Rinckenberger t state that 

 their 



* Compare Hantzsch, Ber. d. chem. Ges., XXXII. 575-641, and also the ortho- 

 benzoldioxime of Zincke and Schwarz, Ann. Chem. (Liebig), CCCVII. 28. 

 t Ber. d. chem. Ges., XXXII. 628. t Ibid. 



