OF AROMATIC COMPOUNDS. 73 



from p-nitr aniline, p-ami^o-phenol-sulphonic acid 

 from p-nitro-phenol, and p-amido-phenol-sulphonic 

 acid from p-chlor-nitro-benzene. 



They explain the reactions in the following manner: 



C H ' C H 



( -' H 'CH, " C ' H '\CH,OH, 



. /NO, 

 C 6 H S CH 3 

 \NH a 



/NO, 



The phenomena of the reduction of nitro-com- 

 pounds in alkaline solution have been investigated by 

 Lob. 1 In his first experiments he used nitro-benzoic 

 acids and nitro-phenols. It was found that m-nitro- 

 and p-nitro-benzoic acid were smoothly reduced to the 

 corresponding azo-acids, while the o-acid under simi- 

 lar conditions yielded o-azoxy-benzoic acid and o-hy- 

 drazo-benzoic acid. The nitro-phenols in alkaline 

 solutions gave amido-phenols. 



The fact that the reduction in an alkaline solution 

 may be carried as far as the azo-phase has been made 



1 Zeitschr. f. Elektroch., 2, 529: ibid., 3, 45. 



