128 



UNIVERSITY OF COLORADO STUDIES 



The compound resulting from a condensation of mesityloxide and 

 orthophenylene-diamine, having the formula C 12 H l6 N 2 , and contain- 

 ing two imido groups, could have any of the following constitutional 

 formulas : 



/\c„_ c / CH ' 



^X^^ 



f 



CH, 



rH, 



\^ni^ C - CI \h. 



S~^*K 



in 



vNnK 



CH • CH, 



c=cf 



N CH, 



IV 





Formula I represents a dihydro-benzimidazole. Very few compounds 

 of this class are known, and they are very unstable, oftentimes oxidizing 

 to benzimidazoles on crystallizing. Gentle warming with dilute acids 

 is sufficient to decompose them. 1 Since the compound here obtained 

 is a stable diacid base, it seems most unlikely that it should have a con- 

 stitution corresponding to I. The green fluorescence obtained by oxi- 

 dizing the base would militate against Formula I. 



Formula IV represents a compound having a ring of seven atoms. 

 Such compounds containing nitrogen in the ring are exceedingly rare, 

 those known being mostly imids of carboxylic acids. 



This leaves for our consideration Formulas II and III. Both of 

 these are dihyhro-quinoxalines, II having a double carbon linkage in 

 the heterocyclic ring, and III having it in the side chain. It seems 

 more probable that II is the correct formula, for in III it would be 



1 Kuhling, Orthoconfansationsproducle, pp. 187, 188. 



