1902.] 



Isomeric Change in Benzene Derivatives. 



155 



less, the diazonium salt being immediately converted into the alkali 

 diazotate.* The latter change may be represented thus — 



c 6 h 2 x 3 .ne;n 



Diazonium salt. 



C 6 H 2 X 3 .N(OH) : .N 



Diazonium hydroxide. 



CoHoXs.NlN-OM' 



Diazotate. 



As the author has maintained on previous occasions, the first step 

 in this type of intramolecular change consists in a transference of the 

 atom or group attached to the nitrogen to the ortho- or para-carbon 

 atom of the nucleus, an ortho- or para-quinone being formed. The 

 complete transformation in the case here described may be represented 

 in the following manner : — 



CI 



N-N.OH 



7% 



ci 



Cl 



/OH 

 \C1 



01 



i. 



v 

 Cl 



II. 



either 



NiN.Cl 



N=N 



~$ 2 



Cl^^OH 



ci fV 



ci./\ 







; or Jj j 









Cl 



Cl 



Cl 



III. 



IY. 



Y. 



In other words, the diazonium chloride (III) may be represented as 

 changing into the " diazophenol " (IV); or, if, following Wolff f and 

 Hantzsch,J the diazophenols are considered to be diazoquinones (V), 

 the ortho-quinone form (II) merely loses hydrogen chloride. 



Closely allied to the intramolecular change just mentioned, are 

 Hantzsch's observations § that s-tribromobenzenediazonium chloride 

 changes into chlorodibromobenzenediazonium bromide, and ehloro- 

 and bromo-benzenediazonium thiocyanates into thiocyanobenzene- 

 cliazonium chlorides and bromides. 



[The following observations of Meldola|| may also be mentioned, 

 as the author's results offer a possible explanation. When dinitro-o- 

 or dinitro-^-anisidine is treated with sodium nitrite in the presence 

 of acetic acid, the nitro-group occupying a position ortho or para 

 with respect to the amino-group is eliminated, a diazophenol (diazo- 



* Professor Meldola has called the author's attention to a French patent 

 (No. 315.932) of the Badische Aniline Company, dated February 28, 1902, in which 

 the replacement of the nitro-group and halogen by the hydroxyl -group by the action 

 of alkalis on diazonium salts, is claimed as a technical process. The author's 

 experiments show within what limits this process is applicable, and what is the 

 probable action of the alkali. 



f ' Annalen,' 1900, vol. 312, p. 119. 



X 'Berichte,' 1902, vol. 35, p. 888. 



§ 'Berichte,' 1896, vol. 29, p. 947 ; 1897, vol. 30, p. 2334; 1898, vol. 31, p. 1253 ; 

 1900, vol. 33, p. 505. 



|| ' Trans. Cheru. Soc.,' 1900, vol. 77, p. 1172 ; ' Proc. Chem. Soc.,' 1901, vol. 17, 

 p. 131; ' Trans. Chem. Soc.,' 1901, vol. 79, p. 1076 ; 1902, vol. 81, p. 988. 



