Acid properties of aromatic aminoazo compounds

1.	The strong bathochromic shift of the absorption bands of aminoazo compounds in acid medium is due to the formation of a cation of quinoid structure.
2.	Aminoazo compounds are weak NH acids in aprotic polar solvents, and they form the corresponding mesomeric anions in the presence of alkalis.
3.	The synthesized aminoazo compounds are very weak NH acids, and electron-donor substituents weaken the acid properties of the amino group, while electron-acceptor substituents intensify them.

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1513–1518, July, 1989.