Azaindole derivatives
The polarographic oxidation of a series of 5-azaindoline, 7-azaindoline, and 5,7-diazaindoline derivatives (22 compounds) was studied, and the results are compared with the ease of dehydrogenation of these substances under the influence of quinones. It is shown that E1/2 increases on passing from 7-azaindolines to 5-azaindolines and then to 5,7-diazaindolines. The effect of substituents is satisfactorily described by cross-correlation equations, while the deviations from the correlation are associated with the peculiarities of the lactam-lactim tautomeric equilibrium in a number of 6-hydroxy-5- and 7-azaindolines.