Simultaneous determination of N-unsubstituted- and N-substituted nitroazoles and criteria for their identification-I Nitroimidazoles and nitropyrazoles-polarographic determination.
The N-unsubstituted nitroazoles have an imino hydrogen atom in contrast to the N-substituted derivatives, and react with hydroxide to give nitroazole anions. The strongly negative shift of E(1 2 ) for these anions makes possible simultaneous polarographic determination of any pair of compounds, one of which is an N-unsubstituted nitroazole and the other a corresponding N-substituted derivative. Simultaneous polarographic determination of three compounds [4(5)- 4- and 5-nitroimidazole] is also possible from alkaline medium, but only when DeltaE(1 2 ) between the N-substituted isomers is at least 100 mV. Chromatographically, and/or by some other criteria it is possible to distinguish between the N-unsubstituted nitroazole and the N-substituted derivatives. These compounds appear together in reaction mixtures arising during substitution of the hydrogen atom.
Dumanović
D
D
Research Laboratory "Galenika," Zemun, Yugoslavia.
Cirić
J
J