526 



(p or m) N0 2 .C 6 H 4 



Prof. R. Meldola on the Theory of the 



N:N M» 



(p or m) N0 2 .C 6 H 4 

 NH.C 6 H 4 .N0 2 (p or m) 



^\0 6 H 4 .N0 2 (porm) 



N:N 



N:N 



(p)N0 2 .C 6 H 4 



(m) N0 2 .C 6 H 4 



C 6 H 4 .N0 2 (m) 



<C 6 H 4 .N0 2 (p) 



m.p. 187°. 



m.p. 174°-175°. 



[The planes of decomposition are represented by the dotted 

 lines.] 



It will readily be seen that these formulas are in harmony 

 with the characters of the compounds which they represent. 

 Thus, taking the products of decomposition of the last pair of 

 isomeric ethyl-derivatives, the 187° m.p. modification is re- 

 solved into p-nitrodiazobenzene-chloride and m-ethylnitrani- 

 fine, while the other modification yields m-nitrodiazobenzene- 

 chloride and p-ethylnitraniline. 



The corresponding pair of isomeric ethyl-derivatives con- 

 taining aniline and toluidine residues, prepared by Nolting 

 and Binder and by Gastiger, may be similarly formulated : — 



CM, 



N:N 



(p) C 7 H 7 



/C 2 H 5 

 \C 7 H 7 (p) 



Keg 



These compounds, which have already been referred to, are 

 decomposed by acids (hot) ; the first into phenol and p-ethyl- 

 toluidine, and the second into p-cresol and ethylaniline. 



The mixed compounds containing both aromatic and fatty 

 radicals are in all respects analogous to the normal compounds, 

 and, according to Wallach*, behave like these on decompo- 

 sition. Thus the typical compounds of this group, first pre- 

 pared by Baeyer and Jager f by the action of diazobenzene 

 salts upon ethylamine, dimethylamine, and piperidine, may be 

 written : — 



N:N 



N 



N:N 



C 6 H 5 



C e H. 



N(CH 8 ) a 



* Lieb. Ann. vol. ccxxxv. p. 233. 



t Ber. deut. chem. Gesell viii. (1875 J pp. 148, 893. 



